Dealing with winter weather in your hoophouse

December lettuce in our hoophouse after snowfall. Photo Pam Dawling

Dealing with winter weather in your hoophouse

We’ve just had Winter Storm Frida bring us a foot of heavy wet snow and, along with most of Virginia, several days without electricity. Six days in our case. Much longer, colder and snowier than I expected. I know, climate chaos makes predictions and expectations chancy! We are in zone 7a, with an average annual minimum temperature of 0-5°F (-18°C to -15°C) until recently.

In November 2018, I wrote a post for Mother Earth News entitled Dealing with Snow on your Hoophouse.

When the power goes out, close the air intake

Hoophouse air intake with a very useful flap to reduce or close the opening. Photo Kathryn Simmons

The first thing an operator of a double layer hoophouse should do when the power goes out (especially in winter) is to rush out and close the air intake. Without electricity to run the little blower, the air intake hole becomes an air outflow. Closing the flap on the blower stops the air escaping. In summer you might not mind, but in winter, the air between the layers of plastic maintains about 8F/5C warmer at night inside than outside, and plants can survive 14F/8C colder than they can outside, without extra rowcover; at least 21F/12C colder than outside with thick rowcover.

The “air bubble” also gives strength to the structure in withstanding loads caused by high winds or heavy snow. Soon after the power cut out on Monday morning, I set out towards the hoophouse. Then I remembered that when we changed the end wall plastic in the fall, we did not fit a cover flap. Worse yet, the air tubing projected out of the wall, making a hasty retrofitting impossible. I briefly considered “putting a sock in it” literally, but then pictured what would happen when the power came back on and sucked the sock into the motor, overheating it and starting a blaze. So, learn from our mistake – always fit a flap over the air intake!

Rolls of rowcover in our hoophouse ready to pull over the beds on very cold nights. Photo Wren Vile

We keep rolls of thick Typar rowcover at the ready and cover the individual beds if we expect the outdoor air temperature to be 8°F (-13°C) or lower. Otherwise we don’t use any inner rowcovers in our hoophouse. Without the insulating effect of the air bubble during the power outage, we decided to use the rowcovers when the outdoor temperature was going to be less than 16°F (-9°C). Several nights like that!

Perhaps this will be your first hoophouse winter. Some others will be remembering last winter, and hoping to find a better way of dealing with snow. Snow can be heavy stuff, so removing it is worthwhile. This can be done from the outside, pulling the snow down to ground level, and from the inside, bouncing the snow off the plastic. It isn’t necessary to remove all the snow. Once you have removed what you can, the daytime temperature inside the hoophouse will rise and help melt the rest of the snow. We have never needed to get out of bed in the night to tackle snow, but you might.

The Snobrum tool we use on the outside of our hoophouse.
Photo Pam Dawling

First we tackle the outside, or if snow is still falling or it’s frozen onto the plastic, we start with the inside. Either way, start with the south side, to get as much advantage from solar gain as possible. The important rule of snow removal is “First, do no harm.” Don’t make holes in the plastic in your efforts to remove snow! A hoophouse is most stable when the snow is evenly distributed. Since houses are stronger at the ends where they have end walls for support, it makes sense to start at the weaker middle and work in both directions if removing heavy snow.

Hoophouse snow scraping tool on a telescoping painter’s pole. (No snow in sight!) Photo Pam Dawling

For outside we use a tool (SnoBrūm™) which is sold for scraping snow off cars. It’s a foam board about 6″ × 18″ (15 × 45 cm) with a threaded insert that takes a telescoping pole. It is sold with a short pole, but a painter’s pole will give a much longer reach. If you haven’t yet got one of these handy tools, carefully use the back of a rake (wrapped in thick cloth). Pull the snow down between the bows, avoiding pulling the tool over the framework as much as possible, as that can easily make holes. Alternate with shoveling the snow away from the base of the hoophouse if the snow is deep (piles of snow pressing against the lower walls can do damage). Be careful not to hit the plastic with any metal tools. Don’t attempt to use the relatively fragile foam-board tool for pushing snow along the ground; keep it free of grit and use it only on the plastic.

Removing snow from a hoophouse at Dripping Springs Garden. Photo Mark Cain

Inside, don a visor (to keep blobs of icy water from landing on your face) and grab an old broom with its head covered in a cloth or bubble plastic, taped on. Make sure there are no sharp protrusions from the broom head. First walk along the paths nearest the walls banging the broom against the plastic. We find a double bouncing action works best, and we can get in a rhythm. This can be a long and tiring job! Start at waist height because if the lower snow falls down, sometimes the higher stuff will follow it down, saving you work. When you need to reach higher, tie or tape the broom to a longer stick. Or find something that screws onto your painter’s pole, such as a paint roller (!) and cover that with bubble plastic. Balance applying your energy with being gentle with the plastic. Do not use the foam-board scraper for bouncing snow — it will crack.

When you’re tired and no more snow is easy to move, wait and try again later. The warming effect of incoming daylight will help melt the snow next to the plastic, so that it is easier to start it sliding off next time you do the rounds.

Sometimes ice accumulates on the plastic. If you get freezing rain that sticks on the plastic, it creates a rough surface that keeps any snow that settles on top from sliding off until the ice thaws. The best way to remove ice is to melt it using warmth from inside. If you have double plastic and it is not windy, switch off the inflation blower — the heat from inside will reach the ice sooner. I recommend against breaking the ice free mechanically, as there is a big risk of the sharp edges of the ice cutting the plastic. You also risk abrasion every time you use a device on the outside of the plastic to pull snow or ice off the tunnel. This makes the plastic rough, and snow won’t slide off as well in the future.

Prevent Hoophouse Frame Collapse

Snow comes in various consistencies and weights. A foot (30 cm) of light fluffy snow may only contain as much water as 1″ (2.5 cm) of rain. But heavy wet snow can equal 1″ (2.5 cm) of rain in only 3″–4″ (8–10 cm) of snow. Each inch (2.5 cm) of rainwater-equivalent will load a structure with 5.2 lbs/ft2 (25 kg/m2). This is about 6.5 tons (5.9 metric tons) on a 25′ × 96′ (7.6 × 29.2 m) hoophouse! Uneven snow loads make a frame more likely to collapse because there are points of higher pressure. This happens if snow is thicker on one side of the hoophouse or if adjacent hoophouses are too close and snow piles up between them when it slides off the roof. The weight of snow can buckle the side of the frame.

Some growers have wood posts ready to wedge under the trusses for extra strength. It sounds like a good plan. Our hoophouse doesn’t have any crosswise trusses, just lengthwise purlins. It’s still standing after 18 years.

When heavy snow is predicted, turn a heater on a couple hours before the storm begins, with the thermostat at 70°F (21°C) or higher. The cost of the fuel is less than a new hoophouse. A portable propane heater (non-electric!) is a good thing to have on hand for unheated tunnels or if a furnace fails or if the power goes out. If you have a very heavy snowfall and it is not possible to remove the snow, then cut the plastic and let the snow fall into the hoophouse to relieve the pressure and save the frame.

“If this, do that”

We have an “If this, do that” card at the front of our hoophouse log book, to help with decisions. It divides snow events into three types.

  1. If the night temperature will be higher than 25°F (−4°C) and you expect less than 6″ (15 cm) of wet snow, leave the inflation blower on, go to bed and hope the snow will slide off.
  2. If the night temperature will be lower than 25°F (−4°C), or there will be more than 6″ (15 cm) of snow and no wind, turn off the blower until the morning, letting the interior heat do its best to melt the snow. If it’s going to be extremely cold, you’ll have to balance this with your need to keep your crops alive.
  3. If there is hard sleet or freezing rain, cycle the inflation off for three hours, on for three hours, with the goal of letting the interior heat melt some of the accumulation, and then using the inflation to push the slush off (give it some help in the morning). Repeat this cycle as needed.

Two great resources are Vern Grubinger, University of Vermont Extension, Prevent Greenhouse Collapse and the Rimol Greenhouses Blog How to Reduce Storm Damage to Your Greenhouse and High Tunnel.

In November 2020 I wrote Winter Preparations for Vegetable Gardens

Winter-Kill Temperatures

My annual blogpost of Winter-Kill Temperatures for Cold-Hardy Vegetables is always very popular. Usually searches for this info increase in October and peak in early November, when growers are deciding when to harvest each crop as the cold increases. In mid-winter you might consult the table to determine which crops to prioritize for extra rowcover if a bad thing happens.

I have learned that there is more damage when the weather switches suddenly from warm to cold. And that the forecaster in Raleigh, NC says it needs 3 hours at the critical temperature to do damage. Also note that repeated cold temperatures can kill off crops that can survive a single dip to a low temperature, and that cold winds, or cold wet weather can destroy plants quicker than simple cold.

Workhorse Crops for January

Our hoophouse with a December snowfall. Pam Dawling

We’re solidly in the darker and colder half the year for our monthly series of 14 Workhorse Crops (asparagus, beans, cabbage, carrots, chard, collards/kale, garlic, potatoes, sweet corn, sweet potatoes, tomatoes, watermelons, winter squash, zucchini/summer squash). These crops are reliable and productive under a range of conditions. You can use the search box to find previous month’s entries, such as December.

Winter is a natural opportunity to reconsider the size of your garden, which crops to grow, and your growing methods. Perhaps this will be your first gardening year? If so, welcome! Use the search box to find specific info, or click the blog category to find some further reading. Hopefully, we all have our garden plans made and our seeds ordered. Maybe we are already looking at a planting schedule.

Workhorse Crops to Plant in January

Potato Onions

Yellow Potato Onions.
Photo Southern Exposure Seed Exchange

In January, we can plant small small potato onions outdoors.  We prepare the bed in the late fall and mulch it with hay, to plant in January. We rake off the mulch, plant the onion bulbs and then lay the mulch back on the bed, to control weeds and somewhat to insulate the little onion bulbs. These smallest potato onions are very cold-hardy, and will grow up to produce a single 3” (7.5 cm) large onion. A few will grow and subdivide to produce more small onions. Click the link to read the details.

Indoor sowings for later transplanting outside or in the hoophouse

In our greenhouse we fire up our germinator cabinets and sow our first lettuce and early cabbage (Early Jersey Wakefield and Faroa) and scallions in mid-January. The following week we sow our tomatoes to plant out in the hoophouse, and at the end of the month, spinach if we have not got enough sown in our hoophouse to transplant as bare-root transplants.

Flats of cabbage seedlings in our greenhouse.
Photo Pam Dawling

Hoophouse workhorse crops to plant in January

In the hoophouse we are sowing a second or third round of crops, mostly successions of greens and radishes. We have already pulled our first and second radishes, and some of the Asian greens.

This March we will be using a half-bed in the hoophouse for some early green bush beans. Like our other warm weather crops, these can be planted in the hoophouse a month earlier than outdoors. Two cautions with green beans in the hoophouse: buy a very upright variety, as the plants will be more sprawling than they are outdoors. Outdoors we grow Provider and Bush Blue Lake (both very reliable and productive), and in the hoophouse we like Strike. The second bean caution is that we have found the edge beds too cold for beans when we need to sow them, in March. Don’t plant them now, but order seeds of an upright variety and plan a non-edge bed. I’ll say more in March.

We have also planned our next round of early warm-weather crops, which we will transplant in late March and early April. Tomatoes and zucchini/summer squash are on our Workhorse list

Young spinach seedlings.
Photo Pam Dawling

We stop filling gaps in most of the Asian greens at the end of December, because they will start to bolt in January and/or because they are mature and we will be clearing the space to sow something else. Tatsoi, Tokyo Bekana, Pac Choi, Chinese Cabbage, Yukina Savoy, all need to be eaten during January.  We sow spinach (the Racehorse Crop) in mid-January, to transplant in the hoophouse and outdoors.

Vates kale seedlings for bare-root transplanting.
Photo Pam Dawling

On January 24 we sow Vates kale and Morris Heading collards in the ground in the hoophouse, in the space recently freed up by the Chinese cabbage. For 1080ft outdoors, we need 108ft of seedling rows. We can fit 14 rows of seedlings across a 4ft (1.2 m) bed.

See November’s information on Follow-On Crops, and Filler Greens (short rows of greens sown in October to fill unexpected spaces).

Workhorse Crops to Harvest in January

We still have workhorse crops to harvest outdoors: chard, kale and collards, and perhaps cabbages. We’re down to three of our 14 workhorse crops to harvest outdoors in January, but we have the Racehorse Crop, spinach, too, and also luscious hoophouse greens.

Deadon (105d winter cabbage) is extremely cold hardy – we leave it outdoors until nights threaten to hit 10°F (-12°C), the lowest temperature I’ve seen it survive. We just had one night at that temperature, much colder than anything else so far this winter.

Chard can still be harvested outdoors if we covered it with hoops and rowcover. The outdoor killing temperature for unprotected Bright Lights chard is 22°F (–6°C); red chard survives down to 15°F (–9.5°C) and green chard to 10°F (–12°C). We have succeeded in keeping chard alive outdoors right through the winter, if we cover it.

Collards and Kale can be lightly harvested in January. Our mnemonic for sustainable harvesting of leafy greens is “8 for later”, meaning we leave at least eight inner leaves when harvesting the outer ones, to ensure the plants have enough strength to regrow. In October, November, February and March, we can harvest leaves from these plants once a week. In December and January, once each month is more like what we can hope for. Chard and senposai do OK with only 6 leaves left.

Hoophouse Workhorse harvests in January

We are harvesting leaves from our hoophouse Bright Lights chard at an adolescent size, cutting them into ribbons, and chopping the colorful stems, for salad mixes. Later, when the days lengthen, we’ll be able to harvest leaves for cooking.

Red Russian kale in our hoophouse
Photo Pam Dawling

The Red Russian and White Russian kales are ready to harvest now (we were a bit late with getting a successful sowing in September). Russian kales belong to the napus group of kales, which are better able to make growth in low light levels than oleracea types like the Vates we grow outdoors. Vates is our star outdoors, because it is more cold-hardy than any other kale I’ve found. The Russian kales have a tendency to wilt after harvesting, so we move fast and stand the leaves up in the buckets. We add some water to the buckets before rushing them to the walk-in cooler. (We do this with chard, turnip greens and Tokyo bekana too.)

The hoophouse senposai is on its third round of harvests, just two weeks after the second, which was one week after the first. This clearly demonstrated the slower rate of growth as temperatures and daylight decrease. The short days do cause plant growth to slow down, but this is not the only factor. Soil temperature is another. In our hoophouse, the soil temperature is still 50F (10C) in early January.

But hey! The length of daylight is now increasing! On the shortest day, December 21, we have 9 hours and 34 minutes of daylight, from 7.21 am to 4.55 pm. The mornings continue to get darker by a few minutes, taking a month to get back to 7.21, from a latest of 7.25 am. Meanwhile the evenings are getting lighter, gaining us 6 minutes by January 5. I’m typing this on my laptop onto a USB stick, as we are in day 3 of a power outage. I appreciate the lighter evenings! By January 21 we will be up to 10 hours of daylight!

Workhorse Crops from storage in January

Storage crops come into their own in December and January, once outdoor growth has slowed down. The flavor of stored sweet potatoes reaches its peak in late January! Besides the Workhorse Crops of carrots, potatoes, sweet potatoes, winter squash and garlic, there are many other root crops. See my posts Root Crops for the Month. Use hardneck garlic first, as it stores for only for 4-6 months. Softneck garlic can store for up to 7 months.

Eat up your acorn and other pepo types of winter squash, as they store for only 1-4 months. Maximas such as Cha Cha, Jarrahdale and Kabochas store for 3-5 months; Moschatas such as Butternuts and Cheese pumpkins will store for 8 months or even more. Seminole pumpkin can easily store for a whole year at room temperature. They do have hard shells and need a hefty cleaver to cut them open.

Our white potatoes are keeping well in the root cellar down at 40F-50F (5C-10C). We air it about once a week. We open the door on mild nights or chilly overcast days, depending what we get and what we need. Potatoes in storage after their first month are no longer respiring much at all. They should be dormant, and not in need of many air changes.

Sweet potatoes on a plate.
Photo Brittany Lewis

Our sweet potatoes are very delicious. We are eating about 40-50lbs (19-23 kilos) a week.

Stored cabbage can also be a boon, and this is also a good time to explore all the pickles and canned and frozen produce you put up earlier.

Workhorse Crops Special Topics for January: Making Schedules.

Screenshot Crop Planning Cycle

We continue our Garden Planning, ordering seeds and planning schedules of field planting and greenhouse seedling starting. In January we start sowing seeds indoors, and need our schedule figured out for that. We also need to pay attention to germination temps for various crops, so that we get them off to a good start, matched with crops needing similar temperatures in each germination cabinet.

Using all the space in the winter hoophouse

Mid-October photo of September-sown tatsoi and August-sown Tokyo bekana. Fast-growing crops make good use of small windows of time throughout the year.
Photo Pam Dawling

Quick crops to fill hoophouse space Oct 1-Nov 29

This fall we had unused space in a bed where we planted Oct 1 radishes and Tokyo bekana (transplanted), Oct 2 brassica salad mix and Chinese cabbage and Oct 3 pak choy. On Oct 4 we had planted only 44ft, half the bed.

On Oct 10 we made a tiny 1.5ft sowing of brassica gap-filler plants. Oct 20 and 23 we did a bit more planting: scallions, radishes and more filler greens and lettuces (12.5ft), leaving 30ft still empty after Oct 23.

The next plantings were more fillers on Nov 9 (5ft), tatsoi on Nov 15 (7ft), radishes on Nov 29 (2ft), total 14ft more, leaving 16ft still empty. Then came lettuce mix on Dec 7 (12ft), leaving 4ft for brassica salad mix #2 on 12/18. Weeks of bare soil – ugh!

Then we start clearing the first round of crops (clearing radish #2 for Dec 8 brassica salad mix #1.5, 2ft) and Dec 18, clearing 4ft of radish #2.5 south side only,  for more brassica salad mix #2, Dec 23 (clearing brassica salad mix #1 for radish #5, 4ft).

If we have a similar crop arrangement next winter, or small empty patches in various beds, what can we plant in space that is still empty after Oct 10, and especially the spaces that don’t get planted until mid-November onwards? We could try different crops, for the various crops that follow.

Qualities of possible crops:

  • Ready to eat 19-83 days from sowing or transplanting. Most spaces 30-60 days.
  • Cold weather crops, not warm weather crops
  • Something we’ll want to eat then, that we don’t already have lots of.
  • Or something that could be processed for later (we generally have enough greens in winter)
  • Maybe not spinach, as it’s a challenge with pests in the fall.
  • (Preferably not brassicas as we grow so many and stretch the crop rotation.)

Ready to eat 21-60 days from sowing

In order of earliness:

Pea shoots make a delightful salad ingredient.
Photo Pam Dawling

Tips (based on Johnny’s Key Growing Info):

  • Grow when the weather is warm 65°F (18°C). Hmmm?
  • Soak seeds for 8 hours (do not re-use water).
  • Sow seeds thickly and lightly press seeds into soil. Shade?
  • Keep moist.
  • Shoots should be at an edible size (3–6″) within 7–21 days.
  • HARVEST: Using a sharp harvest knife or scissors, cut the shoots just above the soil line. Place in plastic bags or sealed containers and refrigerate. [Could use up leftover pea seed that won’t be any good next spring]
Our outdoor Eat-All greens in October. Photo Bridget Aleshire

Eat-All Greens (35 days from sowing). Invented by Carol Deppe, as a method of growing cooking greens quickly with little work, direct sown and cut at 12″ tall, leaving the tough-stemmed lower 3”, perhaps for a second cut, or to return to the soil. She recommends 7 greens in particular: Green Wave mustard, Shunkyo and Sensai radishes, Groninger Blue collard-kale, Burgundy amaranth, Tokyo bekana, and Red Aztec huazontle. We tried this outdoors one fall, and I wrote 3 blog posts about it. The crops that did best for us were fava beans, peas, radish greens, Maruba Santoh and Tokyo bekana, frills, turnip greens, Siberian kales. The ones that didn’t work outdoors were kohlrabi, beets, and chard. (We sowed old seeds we had, didn’t buy the recommended ones)

  • Earlier turnips (45d)
  • Beets and their greens (easier than spinach and a double crop) (50-60d)

Ready to eat 30-60 d from transplanting

(in order of earliness):

 

  • Earlier Senposai – but we have outdoor senposai to harvest in Oct and Nov (40d from emergence after sowing; 20 days from transplant)
  • Komatsuna (45 days from emergence after sowing; 25 days from transplant)
  • Kohlrabi (45-60d from 25-40d from transplants)
  • Earlier Napa cabbage (Blues) (52 days from emergence after sowing; 32 days from transplant).
  • Fedco Red Dragon Chinese cabbage (60 days from emergence after sowing; 40 days from transplant)
  • Small early cabbage like Farao, Golden Acre and EJW are all about 62 days from emergence after sowing; 42 days from transplant
  • Broccoli Tendergreen is 67 days from emergence after sowing; 47 days from transplant

Ready to eat 90 days from planting

Garlic scallions outdoors in late March. Think what might work in a hoophouse! Photo Pam Dawling
  • Garlic scallions. We normally plant these in early November and eat in early March (120 days). But if we plant them earlier, in a warmer place, they’ll be ready sooner. Normally you don’t want to plant garlic until the soil cools to 50F (10C), because it would grow too fast and not survive the winter. But if it’s just the scallions you want, the rules change. . .

Clif Slade, who farms in a slightly warmer climate zone in Surry, Virginia, tells me they plant garlic for scallions outdoors in every month except August, and in the hoophouse until January (from September?). December plantings are ready indoors in March, outdoors in April. He generally reckons 90 days from planting to harvest, in warm conditions. Any garlic is suitable. Hardneck, softneck, small cloves, large cloves, whole small bulbs. Best return is on small garlic, although bulbs with lots of small cloves can be tiresome to pull apart!

When to sow crops to transplant?

And how would this fit into our schedule?

  • We’d need to sow 3-4 weeks before a transplant date of Oct 1, thst’s Sept 1-7.
  • We could sow Sept 15 with our first round of hoophouse transplants. Transplant Oct 7-15 approx
  • Start the hoophouse nursery bed two weeks earlier?
  • Or sow in the lettuce nursery seedbed which is already in use in early September?
Bull’s Blood beet greens are the most beautiful addition for salads or can be cooked.
Photo Pam Dawling

It looks like we might have 30ft total available for fast crops. Here’s what fits:

  1. Oct 1-Oct 20, 12.5ft. 19 days. Pea shoots, small transplanted senposai.
  2. Oct 1-Nov 9, 5ft. 39 days. Eat-All Greens, transplanted senposai, komatsuna, or kohlrabi, or pea shoots. Maybe garlic scallions.
  3. Oct 1-Nov 15, 7 ft. 45 days. Turnips, transplanted Blues, Red Dragon, small cabbages, or as in B.
  4. Oct 1-Nov 29, 2ft. 59 days. Beets and beet greens, or transplanted Tendergreen broccoli, or as in C.
  5. Oct 1-Dec 7, 12 ft. 67 days. Any of the above
  6. Oct 1-Dec 23, 4 ft. 83 days. Any of the above.

Caution about slow growth

Growing slows down in November and December, so maybe we should be cautious the first time and add 10-14 days to the days to maturity??

Radishes

Cherry Belle radishes in our hoophouse.
Photo Pam Dawling

Some years ago I figured out a sequence of sowing dates that would give us an even radish supply, without gaps or gluts. For various reasons, we drifted away from those dates, and I’d like to get back to them again. Sept 6 is the earliest we can sow in the hoophouse. Jan 25 is the latest date that will give us a worthwhile harvest, starting Jan 27. Skipping that last one would be OK.

#1 #2 #3 #4 #5 #6
Suggested Sept 6 Sept 30 Oct 27 Nov 23 Dec 20 Jan 25
Sowing interval 24 days 27 days 27 days 27 days 36 days
Harvest start Oct 1 Nov 4 Dec 8 Jan 11 Feb 14 Mar 20
Harvest interval 34 days 34 days 34 days 34 days 34 days

Workhorse Crops for December

Multicolored chard from our hoophouse.
Photo Wren Vile

We’ve entered the colder half the year for this monthly series of 14 Workhorse Crops: asparagus, beans, cabbage, carrots, chard, collards/kale, garlic, potatoes, sweet corn, sweet potatoes, tomatoes, watermelons, winter squash, zucchini/summer squash. These crops are reliable under a wide range of conditions.

I hope this blogpost series will help you become more productive and profitable (if selling) as you go into winter. Maybe you gardened for the first time this year, or expanded production in spring (orders to seed companies suggest many people did!) Maybe you have less time at home than you expected when you started planting in spring. Winter brings a natural opportunity to reconsider the size of your garden, your crops, and your methods.

You can use the search box to find previous month’s entries, such as November.

Workhorse Crops to Plant in December

If you are in a warmer climate than our zone 7a, you may still have the chance to plant garlic.  See Workhorse Crops for November.

Garlic scallions prepared for sale. Typepad.com

Garlic scallions

We could still plant garlic scallions in December. See Garlic Scallions and  October’s Workhorse Crops  post for information about planting garlic scallions (baby garlic plants).

Garlic scallions can be grown at many times of year. This is news to many of us! By planting later it is possible to extend the garlic scallion harvest period out later. It is important to plant them in conditions where they can grow some good roots before getting too cold. Roots can grow whenever the soil is not frozen. Tops grow whenever the air is above 40°F (4.5°C) Planting in a hoophouse in November or December could possibly provide earlier garlic scallions then planting outdoors in early November. Because the plants are growing faster in warmer conditions. I have not tried this myself yet.

Bulb formation and drying down of bulb garlic is controlled by daylength, but because you do not need bulbing and drying down, all sorts of dates are possible!

Yellow potato onions.
Photo by Southern Exposure Seed Exchange

Potato Onions

We could plant small and medium-sized potato onions outdoors in December.  We have usually also prepared a bed and mulched it with hay, to plant the small potato onions in January. Click the links to get the details.

Hoophouse workhorse crops to plant in December

In the hoophouse we now have all the space fully planted. We intend to do this by November 20 each year, or earlier. We are starting to plant a second round of crops, mostly successions of greens and radishes. We have already pulled our first radishes (which sound like they are sneaking their way into being classified as a workhorse crop!)

Unusually, this fall, we found ourselves with some open space during October and November. I am pulling together information on fast crops we could grow in future years, before the late November and early December crops.

Once we have our hoophouse fully planted, we replace any crop we harvest, keeping all the space fully used. See November’s information on Follow-On Crops, and Filler Greens (short rows of greens sown in October to fill unexpected spaces.

Vates kale – our winter outdoor favorite.
Photo Bridget Aleshire

Workhorse Crops to Harvest in December

We can still have plentiful quantities of workhorse crops to harvest outdoors: cabbage, carrots, chard, kale and collards, and also luscious hoophouse greens. Only four of our 14 workhorse crops can be harvested outdoors in December, but the quantities are good, and we have the Racehorse Crop, spinach, too

We had our first frost of 2021 on November 3 – our latest first frost in the past fifteen years (approximately) has been November 15 2019.

Cabbage We harvest fall-planted cabbage from September 25 until November 30, or perhaps early December in milder years. Deadon (105d winter cabbage) is extremely cold hardy – we leave it outdoors until nights threaten to hit 10°F (-12°C), the lowest temperature I’ve seen it survive.

Carrots can be harvested in December, if we didn’t finish the job in November and we don’t want to risk feeding voles by leaving the carrots in the ground over the winter.

Chard can still be harvested outdoors if we covered it with hoops and rowcover. The outdoor killing temperature for unprotected Bright Lights chard is 22°F (–6°C); red chard survives down to 15°F (–9.5°C) and green chard to 10°F (–12°C). We have succeeded in keeping chard alive outdoors right through the winter, if we cover it. This year, we have abandoned it, as we ate so much chard through the summer and got tired of it! The chard did very well, and we lacked other summer greens like stored spring cabbages, and fall broccoli.

Alabama Blue collards.
Credit Southern Exposure Seed Exchange

Collards and Kale can be lightly harvested in December. Our mnemonic for sustainable harvesting of leafy greens is “8 for later”, meaning we leave at least eight inner leaves when harvesting the outer ones, to ensure the plants have enough strength to regrow. Chard and senposai do OK with only 6 leaves left.

Hoophouse chard in December.
Photo Wren Vile

Hoophouse Workhorse harvests in December

We have started harvesting our hoophouse Bright Lights chard in small amounts, cutting the leaves into ribbons, and chopping the colorful stems, for salad mixes.

The Red Russian and White Russian kales are usually ready from early December. This year we suffered from poor germination (old seed!) and the later resows are still too small. We have plenty of other greens to eat, from outdoors, and the hoophouse senposai is on its second round of harvests, just one week after the first.

Workhorse Crops from storage in December

Storage crops start to come into their own in December as outdoor growth slows down. Besides the Workhorse Crops of carrots, potatoes, sweet potatoes, winter squash and garlic, there are many root crops. See my posts Root Crops for the Month. Use hardneck garlic first, as it stores for only for 4-6 months. Softneck garlic can store for up to 7 months.

Know your winter squash! Use the ones with the shortest storage life first (and any damaged squash that won’t store longer). Acorn and other pepo types of winter squash store for 1-4 months; Maximas such as Cha Cha, Jarrahdale and Kabochas store for 3-5 months; Moschatas such as Butternuts and Cheese pumpkins will store for 8 months or even more. Seminole pumpkin can easily store for a whole year at room temperature.

Our white potatoes were sorted two weeks after the harvest. This one sorting makes a lot of difference to the quality and quantity of potatoes we will be able to eat. After two weeks, very little further rotting starts up. We cool the root cellar down to 50F after the first month, then to 40F, airing once a week (or less if cooling is not needed).

Sweet potatoes stored in off-duty wood seed flats.
Credit Nina Gentle

Our sweet potatoes are fully cured and delicious. We grow 4 kinds: Georgia Jet and Beauregard in roughly equal amounts, to hedge our bets; and two unnamed varieties we call Bill Shane’s White and Jubilee, in small quantities simply to preserve the genetic diversity. Georgia Jet is a bit faster (90 days compared to 100 days) and usually yields a little better for us than Beauregard.  Some New York growers report problems with Georgia Jet due to soft rots and malformed roots. Most growers really like this variety. Beauregard has light rose, red-orange or copper skin, dark orange flesh, uniformly shaped roots. Georgia Jet has a skin that is red-purple. I sometimes find the roots hard to tell apart when we have accidentally mixed them.

Garlic shoots poking through the mulch.
Photo Pam Dawling

Workhorse Crops Special Topics for December

One task for us this month is to Free Trapped Garlic Shoots

14-16 days after planting, when we can see that more than half of the shoots have emerged, we free any garlic shoots trapped under particularly thick clumps of mulch. We investigate the spots where there should be a plant but isn’t. Ours are planted 5” (13 cm) apart. If we find garlic tops, we simply leave part of them exposed to the light. They will sort themselves out. We don’t leave any soil exposed, because we don’t want weeds to grow. This needs to be a fast-moving, efficient task, as there are thousands of plants. It’s also important to be patient and optimistic, and not start this job too early. The goal is to free the shoots that wouldn’t make it out unaided. Not to prematurely expose them all.

In December we continue Planning, including insurance crops. We calculate how much seed to buy, browse the catalogs, balancing trying different varieties on a small scale, and largely sticking to known successful varieties. See my recent post Reading Between the Lines in the Seed Catalogs. We hope to get our seed orders placed before the end of December. Since the Covid pandemic, lots more people have started growing food. This has led to some seed shortages. So if your heart is set on certain crops or certain varieties, order early to avoid disappointment. And to spread out the massive workload that the people working packing and shipping your seeds are dealing with. Appreciate them!

Growing Turmeric

Freshly dug turmeric roots.
Photo Pam Dawling

Our Crop Goals – Does Turmeric Fit?

I have never grown turmeric before, so this article is really my research and plan-making for next spring!

We have grown ginger in our hoophouse, and I’ve written about that in my book The Year-Round Hoophouse. In our zone 7a climate, ginger has to be started with heat in mid-March, and transplanted into our hoophouse in May, when the soil is 55°F (13°C) and rising. It then occupies the space for five months until October, when we harvest it before it gets too cold (it has no frost tolerance). Ultimately we decided to stop growing ginger. It is delicious, and if we were selling our crops, we might have made good money. But we are not selling; we grow food for direct use in our intentional community (Twin Oaks). Our goal is a wide range of healthy organic crops year-round to comprise as much of pour diet as possible. We need crops that provide a lot of nutrients over the time. Hoophouse crops are occupying valuable land, and fast-growing crops are more valuable than slow-growing ones. Cindy Conner’s “Bed Crop Months” is a concept more useful to us than $/sq ft. Crops that fill bellies and provide vitamins and fiber are more valuable than ones that provide only a little food. So, why turmeric?

A hoophouse with turmeric and carrots.
Photo Pam Dawling

About Turmeric

I was given two “hands” of turmeric roots by a farmer who was my guest. Turmeric has medicinal value, and (for me) novelty value, so I asked my hoophouse crew colleagues if I could grow a couple of plants next year. We have a tradition of accommodating small special projects of the crew. This winter we are growing some carrots in the hoophouse for the first time. I know lots of other growers produce carrots in hoophouses. We can grow perfectly good carrots outdoors in the fall, to store and feed us all winter. What do we gain by growing a few in the hoophouse? We’re about to find out.

Turmeric, if grown to maturity, will need from late April to October in our hoophouse, longer than ginger does. Both crops finish in time to plant those vital winter greens in late October.

Turmeric roots look like ginger but are more orange. Turmeric is easier to grow than ginger, but the market is smaller. Turmeric needs less feeding than ginger and as the rhizomes grow out and slightly downwards, it only needs slight hilling if the roots appear above the soil as it grows. Turmeric plants go dormant after 8–10 months of growth, at which point the roots are fully mature and can be saved to regrow next season.

A healthy hoophouse bed of turmeric.
Photo Pam Dawling

Using Fresh Turmeric

Turmeric doesn’t have to be dried and powdered before using—the flavor of the fresh root, whether grated or sliced, is earthy and slightly zingy. You can eat it raw like a carrot. You can grate it and make tea.

If you want to dry it, slice it thinly with a mandolin or a powered kitchen slicing machine. Having the pieces all of the same thickness will make for more even drying. Dry pieces may be ground with a coffee grinder. The distinctive yellow spice powder is used to flavor many Asian-inspired dishes. Turmeric contains curcumins which have valuable medicinal properties (reducing inflammation). The powder may be put in capsules to be taken medicinally.

Buying Turmeric Roots

Hawaiian Clean Seed, Puna Organics and Biker Dude sell turmeric roots shipped from Hawaii. Fool’s Paradise Farm, formerly Qualla Berry Farm, in North Carolina, sells both ginger and turmeric plants and sometimes galangal, another tropical root. They are now harvesting four varieties of fresh turmeric, available from now into December: Hawaiian Red, Indira Yellow, BKK, and Black.

If necessary, you can try growing turmeric from fresh grocery store roots, although they may have been treated with a sprouting inhibitor. When you buy turmeric rhizomes (if you are face-to-face with them) choose sturdy firm roots with many knobby leaf buds. If the knobs are slightly green, that’s a sign that they’re ready to sprout.

A quonset style hoophouse filled with turmeric in North Carolina
Photo Pam Dawling

How to Grow Turmeric

Late winter and early spring is the best time to plant turmeric. Snap the rhizomes into 2″ (5 cm) pieces, and keep them at room temperature for a few days to cure. Seed pieces weigh 1–2 oz (30–60 gm) each. Before planting, soak the root pieces in lukewarm water for a few hours. Cover the rhizomes with 2″–3″ (5–7.5 cm) of potting soil and water lightly. Set the crates of planted roots on a seedling heat mat in a plastic tent or in a germination chamber to sprout. Water the crates when the soil dries out, but do not over-water. It takes 2–4 weeks for the roots to sprout. When this happens, take them off the heat mat.

Grow your turmeric plants in your greenhouse until the danger of frost has passed, then plant them out into the hoophouse. The plant spacing is 6″ (15 cm) between seed pieces. Before planting, add some compost to the soil to improve the fertility. Afternoon shade is helpful. Feed the turmeric plants every few weeks during the growing season. Water daily in summer, with about 1″ (2.5 cm) of water each week. The plant will grow to 2’–3′ (60–90 cm). Turmeric plants may produce flower stems in late summer.

Turmeric growing outdoors in North Carolina. Hoophouse growing is recommended.
Photo Pam Dawling

Harvesting Your Turmeric

Because the plants are frost-tender, plan to harvest before your first expected frost. The plants will probably have begun to die back. Wear gloves when harvesting as the roots can stain your hands bright yellow! Dig up the plants, brush off excess soil and cut off the leaves just above the roots. Snap the roots apart as needed.

Once you grow your first crop you can build up seed stock of your own. Save pieces for replanting but don’t replant them right away. Store these roots unwashed in a plastic bag or box in a refrigerator until late winter. Turmeric is hardier than ginger, although frost-tender, and one grower in North Carolina reported overwintering plants outside in milder years, although the recommendation is to bring them in for the winter.

Workhorse Crops for November

Planting garlic

Here’s another episode in my monthly series of 14 Workhorse Crops: asparagus, beans, cabbage, carrots, chard, collards/kale, garlic, potatoes, sweet corn, sweet potatoes, tomatoes, watermelons, winter squash, zucchini/summer squash. These crops are reliable under a wide range of conditions. We’re half-way through the year for this series, and entering the colder half.

I hope this focused series will help you become more productive and profitable (if selling) as you go into winter. Maybe you gardened for the first time this year, or expanded production in spring (orders to seed companies suggest many people did!) Maybe you have less time at home than you expected when you started planting in spring. Winter brings a natural opportunity to reconsider the size of your garden, your crops, and your methods.

You can use the search box to find previous month’s entries, such as October.

Workhorse Crops to Plant in November

November in central Virginia is the time to plant garlic, but not much else outdoors. We could also plant garlic scallions and medium-sized potato onions.

In the hoophouse we are working to get all the space fully planted. We intend to do this by November 20. The really busy hoophouse planting month of October is successfully behind us. This year we are trying some carrots (we sowed those in September). We have plenty of other crops that don’t qualify as workhorses too!

Garlic

When to plant garlic

  • Fall-planting is best. Garlic emerges quickly in the fall
  • 9 am soil temperature 50°F (10°C) at 4” (10 cm) deep. We plant in early November. If the fall is unusually warm, wait a week.
  • Roots grow whenever the ground is not frozen
  • Tops grow whenever the temperature is above 40°F (4.5°C).

I have written a lot about garlic. Here are links to the most timely ones.

14-16 days after planting, when we can see a lot of emerged shoots, we go back to the garlic beds and free any shoots trapped under particularly thick clumps of mulch. We do this by exploring the spots where there should be a plant but isn’t. If we find garlic tops, we simply leave part of them exposed to the light. They will sort themselves out. We don’t leave any soil exposed.

Garlic scallions ready for harvest in early spring.
Photo Wren Vile

Garlic scallions

Garlic scallions are immature garlic plants, mostly leaves, pulled up before they make bulbs. They are the garlic equivalent of onion scallions (bunching onions, spring onions, escallions).

We plant the culled tiny cloves from the bulbs we save for outdoor garlic planting in early November. Tiny cloves will never produce big bulbs, so growing garlic scallions makes very good use of them! Planting garlic scallions is simplicity itself! Plant the small cloves close together in closely-spaced furrows, simply dropping the cloves in almost shoulder to shoulder, any way up that they fall. Close the furrow and mulch over the top with spoiled hay or straw. See October’s post for more information about planting garlic scallions (baby garlic plants).

Since last month’s post, I remembered learning that you can also grow garlic scallions from surplus or culled bulbs, simply planting the whole bulbs and growing ready-made bunches of scallions! This could be useful if you have small bulbs that no one wants to deal with, or you have some that have started sprouting in storage.

Some growers find they make more money from garlic scallions than from bulb garlic, partly because they don’t have the costs of curing and drying the bulbs! Plus you have a tasty crop to eat and sell in spring, when choices are often restricted to overwintered leafy greens and stored roots. Maybe you have already eaten or sold all your bulb garlic by then.

Some people are working to extend the garlic scallion season. By planting later it is possible to stretch the harvest period out later. Softneck garlic varieties can make worthwhile growth for scallions even if planted after the start of January. See Plant garlic scallions from softneck varieties (Alliums for February). Planting in a hoophouse in November could possibly provide earlier garlic scallions (growing faster in warmer conditions). By planting in a hoophouse, more of the year opens up as a planting season.

I encourage you to experiment with planting a few cloves at different times of year and record your results. Because you do not need to work with the right times for bulbing and drying down, all sorts of dates are possible!

For information about harvesting garlic scallions, see my post Alliums for March. With a last frost date of 20–30 April, we harvest garlic scallions March 10 to April 30 in central Virginia, or even into May, if our supply lasts out, and we don’t need the space for something else.

Two beds of potato onions in spring, of different planting dates.
Photo Kathryn Simmons

Potato onions

I’m cheating here, as these aren’t on the Workhorse list, but November is a good time to plant medium-sized potato onions (a type of multiplier onions). See Alliums for November and Southern Exposure Seed Exchange Garlic and Perennial Onion Growing Guide.

Spinach, the Racehorse

I didn’t include spinach in my Workhorse Crops list, because it’s more of a Racehorse. It does grow quickly, but in spring it bolts quickly. And in September, when we want to sow spinach, we are challenged by soil temperatures that are too hot. It’s a valuable crop under the right conditions. For more, search “spinach”.

Hoophouse workhorse crops to plant in November

We only have a few small areas of crops to plant in November, and none of those crops qualify as Workhorses. Once we have our hoophouse fully planted, we try to keep it that way. I don’t mean we treat it as a museum and touch nothing! I mean we replace any crop we harvest. In some cases, this is part of our plan, with Follow-On crops, as soon as one crop is over.

Filler greens: short rows of Tokyo bekana, Yukina Savoy and senposai used to fill gaps in the winter hoophouse.
Photo Pam Dawling

In other cases it is by using our Filler Greens, short rows of greens that we sow in October in anticipation of some unexpected spaces opening up. You could have plug flats of seedlings for this, but we prefer bare-root transplants, as they are easier to take care of (roots go deep into the soil, and no special watering is needed. If it happens that we don’t transplant them all, we can simply harvest the overgrown seedlings to eat as salad.

A misty November morning in the hoophouse.
Photo Wren Vile

Hoophouse Follow On Crops

A sequence of different crops occupying the same space over time.

  • Nov 17: We follow our 1st radishes with 3rd scallions
  • Dec 23: 1st baby brassica salad mix with 5th radishes
  • Dec 31: Some of our 1st spinach with our 2nd baby lettuce mix
  • Jan 15: Our 1st tatsoi with our 4th spinach
  • Jan 16: Our Tokyo Bekana with spinach for planting outdoors
  • Jan 24: Our pak choy & Chinese cabbage with kale & collards for outdoors
  • Feb 1: Our 2nd radishes with our 2nd baby brassica salad mix
  • Feb 1: Our 1st Yukina Savoy with our 3rd mizuna/frilly mustards
  • Feb 1: Some of our 1st turnips with our 3rd baby lettuce mix
  • Feb 1: More of our 1st spinach with dwarf snap peas
Carrot harvest cart
Photo Mari Korsbrekke

Workhorse Crops to Harvest in November

As I write this, we have not yet had a frost. Four of our 14 workhorse crops can be harvested in November.

Cabbage We harvest fall planted cabbage from September 25 until November 30.

Deadon (105d winter cabbage) is extremely cold hardy – we leave it outdoors until nights threaten to hit 10°F (-12°C).

Carrots: In November we harvest our huge patch of fall carrots, sown at the beginning of August. Some years we have 30 bags of 50 pounds to feed 100 people! But we have had to downsize the garden due to a shortage of workers. I have written about carrot harvest here. We are not particularly fast at carrot prepping. We don’t have a drum root washer. It takes us about 5-6 people hours to get a big (Garden Way) cartful of harvested carrots trimmed, washed, sorted and bagged.

Bucket lid with holes for sorting root vegetables for storage.
Photo Wren Vile

In November it is generally too late for us to sow cover crops, and we don’t want to leave the carrot beds bare all winter. To avoid erosion, we protect the soil by taking the carrot tops back and spreading them out over the beds.

Chard can still be harvested. The outdoor killing temperature for unprotected Bright Lights chard is 22°F (–6°C); red chard survives down to 15°F (–9.5°C) and green chard to 10°F (–12°C). To keep chard alive outdoors over the winter, you can use hoops and rowcover in climates of winter-hardiness zone 6 or warmer. In colder zones, once the temperatures get down near the killing numbers mentioned, make one last harvest, cutting all the leaves just above the growing point. Then pile up mulch over the plants until spring. You could cover the whole heap with rowcover for extra protection. We can soon start harvesting our hoophouse Bright Lights chard in small amounts.

Collards can be harvested in November.

Kale can also be lightly harvested.

Hoophouse Workhorse Harvests

Our first planting of chard in the hoophouse is ready to start harvesting in mid-November, 61 days after sowing. The Russian kales are not usually ready until early December. We have plenty of other greens to eat.

Sweet potatoes on a plate.
Photo Brittany Lewis

From storage: Potatoes, sweet potatoes, winter squash, carrots, and perhaps garlic.

Store garlic above 60°F (15.5°C) or 32°F-40°F (0°C-4.5°C). Never 40°F -56°F (4.5°C-13°C). Last week I said it was OK to store garlic at 32°F -50°F, but newer info says 32°F -40°F (0°C-4.5°C). is better. I’ll edit the previous post. Also avoid reversals of temperature (warm conditions after cooler ones)

Softneck garlic can store for up to 7 months. Hardneck only for 4-6 months.

Sorting potatoes two weeks after harvest, to remove problems.
Photo Wren Vile

With winter squash, use the ones with the shortest storage life first. Pepo types (Acorn) of winter squash store for 1-4 months; Maximas such as Cha Cha, Jarrahdale and Kabochas store for 3-5 months; Moschatas such as Butternuts and Cheese pumpkins will store for 8 months or even more. Seminole (which has a very hard shell) can easily store for a whole year at room temperature.

Our white potatoes will need sorting two weeks after the harvest. This one sorting makes a lot of difference to the quality and quantity of potatoes we will be able to eat. After two weeks, very little further rotting starts up. We also need to cool the root cellar down to 50F after the first month, then to 40F, airing once a week (or less if cooling is not needed).

Workhorse Crops Special Topics for November:

Crop Review, Research, Conferences

Popping garlic at our Crop Review meeting.
Photo Bell Oaks

Crop Review

Every November our garden crew gathers to review how the year went, and what might be done differently next year. See my posts on Crop Review Meetings and here. We usually pop our garlic bulbs apart for planting we sit around talking.

If we have had a particularly difficult year we might look at reducing the number of crops grown. We do this using a points system. See this post. Inevitably, we also have some ideas of new crops we’d like to try, or new varieties of familiar crops. Or new growing methods. This is a good time of year to note down all the suggestions, before the actual plans are made and seeds ordered. See my post How to decide which vegetable crops to grow.

Research

This is also a good time of year to research and evaluate new ideas. Perhaps you made some notes during the year, on your planting schedule.

Conferences

Winter conferences used to be more of a Thing, when we traveled to meet up regionally, browse bookstalls, listen to speakers, meet old friends, make new ones, swap stories, and get re-inspired for another year of hard work. Perhaps we’ll be able to enjoy in-person conferences again in a few months. Meanwhile see my Events Page for presentations I am offering virtually and in the mid-Atlantic. Currently there are more virtual online conferences. These don’t satisfy the itch to talk with other live growers, but many are recorded and they are easier to fit into our schedules. And they do save money. And as Mother Earth News says of their Online Workshops, you can bring your dog!

 

 

Fall and Winter Vegetable Growing, Harvest and Storage

 

China Rose Winter Radish.
Photo Seed Savers Exchange

You can find a wealth of information on my website about growing, harvesting and storing winter vegetables. There are many links here in this post (all should open in a new tab, so you won’t go down a rabbit hole), and you can also use the search box in the upper right to enter whatever vegetable you are wondering about, and “grow” “harvest” or “store”, Remember I also have several annual series of posts, on Asian greens, root vegetables, workhorse crops, alliums, cooking greens, and lettuce. Just don’t look for “Storage lettuce” until April 1st.

I’ve also included some good blogs that I sometimes consult.

  1. Fall and Winter Vegetable Growing

Season extension into cold weather

Prepare your garden for colder weather: plant winter crops if there is still time, use rowcover on hoops to protect crops from wind and cold weather, plant up every little bit of space in your greenhouse or hoophouse.

See my posts

Spinach over-wintered in our cold frame
Photo wren Vile

And here’s a post by Shannon Cowan, the blog editor at Eartheasy.com:

Winter Gardening: Best Crops to Extend Your Harvest

Shannon suggests using a variety of strategies. “Plant some vegetables that will mature quickly, others that will hold well in your garden beds, and still others that will overwinter and begin growing again when the days lengthen.”

This is also my approach. See my posts

Fall-grown senposai.
Photo Pam Dawling

Good late season vegetables: salad greens, Swiss chard, beans, peas (in climates milder than 7), carrots, radishes, senposai, spinach, pak choy, cabbage and winter lettuces.

Good cold hardy vegetables: Plant in late summer and fall to harvest throughout the winter. These late-sown crops reach full maturity before seriously cold weather, and hold so you can harvest them when the rest of your crops have been eaten. They don’t usually grow much during the winter, but they do stay fresh. Grow enough to supply your needs without depending on any further growth. This category includes Asian greens, beets, broccoli, Brussels sprouts, cabbage, carrots, collards, kale, leeks, scallions, spinach, turnips and other root vegetables,

Good crop protection so you can grow some crops through the winter. If your winter temperatures routinely drop below 25 F (- 4 C), crops need protection, from simple rowcover to hoophouses or greenhouses. This improves the temperatures, but it’s hard to address the reduced amount of daylight or sunlight. The increased warmth, plus the protection from winds, can be enough for some, such as spinach, kale and lettuce, to make some growth whenever their temperature is greater than 40F (5C).

Using a sturdy digging fork to harvest leeks in December.
Photo Pam Dawling

Good slow growing crops to harvest outdoors in late winter or early spring. In this category are crops that go into the winter less than fully grown. After the winter solstice, when the days begin to lengthen, crops start growing again, making them usually ready for harvest very early, much earlier than any crops planted after the solstice. They don’t usually need winter protection and include beets, some types of broccoli, cabbage, carrots, collards, kale, onions, garlic, garlic scallions, spinach, kale and collards.

See my post Winter radishes, planting garlic.

Good crops to grow in hoophouses include arugula, beets, chard, Chinese cabbage, collards, kale, lettuce, Maruba Santoh, mizuna, mustards, pak choy, parsley, radishes, spinach, tatsoi, Tokyo bekana, turnips and Yukina Savoy

Hoophouse Bright Lights chard in winter.
Photo Wren Vile

See my posts

  1. Fall and Winter Vegetable Harvest

See my posts

Harvested Purple Top Milan and White Egg turnips.
Photo Pam Dawling

Here are some links to a couple of good sources for more harvest information:

Piedmont Master Gardeners Garden Shed Newsletter

Guidelines for Harvesting Vegetables by Pat Chadwick

A list of seven basic principles of harvesting, followed by a crop-by-crop list of almost 50 individual crops and a resource list of 18 publications (focused on the mid-Atlantic and Southeast)

Roxbury Farm Harvest Manual (Roxbury Agriculture Institute at Philia Farm)

October Tips from Harvest to Table, by Steve Albert covers all climate zones and comes complete with a USDA Hardiness Zone Map

Links to other posts by Steve Albert

  1. Fall and Winter Vegetable Storage

I already have posts on root cellar potato storage, onion storage (alliums for August), Garlic storage, Storage vegetables slide show, Root Crops April, Feb, Jan, Dec, Nov.

See my posts

Sweet potatoes in storage. An ideal crop for winter meals, as they store at room temperature for a long time, maybe seven or eight months. Photo Pam Dawling

Workhorse Crops for October

 

The crew working on the sweet potato harvest.
Photo McCune Porter

This is another episode in my monthly series of 14 Workhorse Crops. These crops are reliable under a wide range of conditions. We’re several months into this series, so here’s the complete list: asparagus, beans, cabbage, carrots, chard, collards/kale, garlic, potatoes, sweet corn, sweet potatoes, tomatoes, watermelons, winter squash, zucchini/summer squash.

I hope to help you become more efficient, productive and profitable (if selling) as you deal with another strange year. Maybe you are not at home as much as last year, or maybe your helpers have gone back to school, but you deeply appreciate sustainably grown food.  You still want to garden, even with less time at home. You can use the search box to find previous month’s entries, such as September.

Workhorse Crops to Plant in October

In October in central Virginia we only have enough remaining good growing conditions outdoors to plant 3 of our 14 Workhorse crops – we can still transplant chard, collards and kale. A big step down from last month’s 8. We could also plant some garlic scallions (the soil is still too warm for us to plant garlic, but if you are in a colder zone than us, you’ll want to see this post.)

In October here, outdoor gardening is more focused on harvesting and less on planting. In contrast, October is our busiest planting month in the hoophouse! In September we direct sowed our first hoophouse bed, and sowed other crops in an outdoor nursery seedbed. Two to four weeks later, in October, we transplant them in the hoophouse. Workhorse crops getting transplanted into our hoophouse in October include Red and White Russian Kales, Bright Lights chard, and Napa Chinese cabbage. This year we are trying some carrots (actually we sowed those in September). We have plenty of other crops that don’t qualify as workhorses too!

Chard:

Swiss chard can be sown outdoors here in September, and transplanted early in October for an early winter harvest, with the option of overwintering under rowcover to provide harvests during the winter. We could direct sow chard in September and protect it for the winter, for a late winter and early spring harvest. Remember that red chard is more cold-hardy than the multi-colored types, and green chards tend to be even more hardy.

Hoophouse Bright Lights chard in winter.
Photo Wren Vile

For hoophouse winter harvest, we sow Bright Lights chard in our nursery seedbed September 15 and transplant it October 16. We love the beauty of the multi-colored chard mixes, both growing and after harvest, and we have found that the hoophouse protects the crop well enough that it does not die, even without inner rowcover (unless the outdoor temperature is forecast to be below 8°F (-13°C).

Collards

This is rather late for us to transplant collards outdoors, but if we need to, and we have some good thick rowcover, we’ll do it. The extra warmth of the rowcover will help it make up for lost time.

Kale

Our last date for sowing Vates kale outdoors is 10/30. We can still transplant August-sown kale to fill gaps if we need to – see August’s post. Because kale makes some growth whenever the temperature is above about 40°F (5°C), it is a valuable winter crop. Our sunnier winter days are often warm enough for kale (and spinach!) to make some growth. We will sow more kale in late January, to give us a spring crop.

Red Russian kale in our hoophouse
Photo Pam Dawling

In the hoophouse we grow both the White Russian and the slightly smaller Red Russian kale. See the explanation about the merits of Oleracea and Napus kales. We make sure to transplant the shorter red kale on the south side of the bed, so it gets adequate light, with the white kale on the north. You may have noticed that red and purple-leaved vegetables grow slower and tend to be smaller than their green cousins. This is because they have less green! Green leaves are needed for photosynthesis, which enables plants to grow. Green plants also contain the reds and purples, but the green dominates. This is similar to the conundrum of red and orange fall leaves – where do those colors come from? They are there all along, but are masked by the green. In preparation for leaf fall, the trees absorb all the green chlorophyll, leaving the fall colors visible.

White Russian kale (napus type) gives us good yields in our hoophouse in winter.
Photo Pam Dawling

Garlic scallions

Garlic scallions are immature garlic plants, mostly leaves, pulled up before they make bulbs. They are the garlic equivalent of onion scallions (bunching onions, spring onions, escallions). Great for omelets, stir-fries, pesto, soups, and many other dishes.

We plant ours using the culled tiny cloves from the bulbs we save for outdoor garlic planting in early November. Tiny cloves will never produce big bulbs, so growing garlic scallions makes very good use of them! Planting garlic scallions is simplicity itself! Plant the small cloves close together in closely-spaced furrows, simply dropping the cloves in almost shoulder to shoulder, any way up that they fall. Close the furrow and mulch over the top with spoiled hay or straw.

You could plant these next to your main garlic patch, or in a part of the garden that’s easily accessible for harvest in spring. We plant our small cloves for scallions at one edge of the garden, and as we harvest, we use the weed-free area revealed to sow the lettuce seedlings for that week.

If you want to have Garlic Scallions to eat or sell in early spring, when new fresh vegetables are in short supply, and homesteaders may be running out of stored bulb onions, see my post Alliums for March. With a last frost date of 20–30 April, we harvest garlic scallions March 10 to April 30 in central Virginia, or even into May, if our supply lasts out, and we don’t need the space for something else. Harvesting is simple, although depending on your soil, you may need to loosen the plants with a fork rather than just pulling. Trim the roots, rinse, bundle, set in a small bucket with a little water, and you’re done!

A colorful salad of rainbow chard, onion scallions and garlic scallions.
Photo (and salad) by Bridget Aleshire.

Rather than dig up whole garlic scallion plants, some people cut the greens at 10″ (25 cm) tall and bunch them, allowing cuts to be made every two or three weeks. We tried this, but prefer to simply lift the whole plant once it reaches about 7″–8″ (18–20 cm). The leaves keep in better condition if still attached to the clove. Scallions can be sold in small bunches of three to six depending on size. A little goes a long way! If you do have more than you can sell in the spring, you could chop and dry them, or make pesto for sale later in the year.

You can plant garlic scallions at other times of year, if you have planting material. See Plant garlic scallions from softneck varieties (Alliums for February). If you plant in a hoophouse, more of the year opens up as a planting season. You can plant whole bulbs (the small cull ones you can’t sell, or don’t want to peel) and grow your garlic scallions already in a clump, rather than in rows of plants.

Some growers find they make more money from garlic scallions than from bulb garlic, partly because they don’t have the costs of curing and drying the bulbs! I encourage you to experiment with planting a few cloves at different times of year and record your results. Because you do not need to work with the right times for bulbing and drying down, all sorts of dates are possible!

Napa Chinese cabbage

Maybe you think I’m stretching things to classify Napa Chinese cabbage as a workhorse, but in my defense, I’ll say firstly that success in farming involves creativity and flexibility, and secondly that the Asian greens as a category are genuine Hoophouse Workhorses, as they grow so well in cool temperatures and short days. It is a cabbage! We sow Blues (53d from transplanting in mild weather) in a nursery seedbed on September 15 and transplant in the hoophouse October 2, at only two weeks old (very fast-growing in September). Because this is a heading vegetable, we leave it to grow to full size before harvesting. That will be in January. Many of the Asian Greens are harvested by the leaf, but Napa cabbage and pak choy are more often cut as a head.

Young Chinese cabbage transplants in our hoophouse.
Photo by Bridget Aleshire

Workhorse Crops to Harvest in October

Eleven of our 14 workhorse crops can be harvested in October (also true in September and August, but with substitutions!) No asparagus, no garlic, no more watermelon. Depending when the frost bites, there will be several fewer harvest options by the end of October.

Beans­ can be harvested until the weather gets too cold. We have covered the beds with rowcover to keep the plants warmer and growing faster. It’s true that pollinating insects can’t get at the flowers to perform their pollination services and make more beans, etc. But that doesn’t matter. We are more interested in fattening up the already pollinated beans! It’s also true that the yields are now way down, so we need to balance the benefits against the costs. Sometimes it is better to clear the crop (and its pests and diseases) and sow a cover crop.

Cabbage We harvest fall planted cabbage from September 25. We like Early Jersey Wakefield (45 days from transplanting) and Farao (64d) for fast-maturing cabbage; Melissa Savoy 85d; Early Flat Dutch 85d, Kaitlin 94d, for storage cabbage which are slower-growing. We have also liked huge Tribute 103d, Tendersweet (71d) for immediate fall use, and Wakamine (70d). Deadon (105d winter cabbage) is extremely cold hardy – we leave it outdoors until nights threaten to hit 10°F (-12°C) . Double-check those days to maturity, I may have mixed days from transplanting with days from sowing.

Deadon cabbage
Credit Johnnys Selected Seeds

Carrots: If we sowed carrots in July, we will be harvesting in October.

Chard can be harvested whenever you want some. This year our chard did extremely well all summer and we are bored silly with it! We wish we had had stored cabbage, or some fall broccoli. We are relishing our fall senposai!

The outdoor killing temperature for unprotected Bright Lights chard is 22°F (–6°C); red chard survives down to 15°F (–9.5°C) and green chard to 10°F (–12°C).

Collards can be harvested in October.

Kale can be lightly harvested, if our early August sowings came through.

Potatoes: We can plant potatoes between mid-March and mid-June, leading to harvests in July-October. Protect potatoes from frost when harvesting. Read more about potato harvest here.

Our March-planted potatoes are in the root cellar. We’ve been eating those since July. We often plan to grow more in the June planting than the March planting, as root cellar storage over the summer is more challenging for us than having them in the ground.

Sweet Corn harvest is still going, thanks to our sixth sowing on July 16.

Sweet Potato harvest at Twin Oaks. Photo McCune Porter

Sweet potatoes need harvesting in October here, before it gets too cold. Usually sweet potatoes are harvested the week the first frost typically occurs. I wrote a lot about this topic here. I wrote all the harvesting details in another post, 10/12/20.

Contrary to myth, there is no toxin that moves from frozen leaves down into the roots. On the other hand, below 55°F (13°C), they’ll get chilling injury, which can ruin the crop. Roots without leaf cover after a frost are exposed to cold air temperatures, and have lost their method of pulling water up out of the soil. I remember one awful year when we left the sweet potatoes in the ground too late, hoping they’d fatten up a bit to make up for a poor growing season. Instead, the weather got cold and wet, and the sweet potatoes were rotting in the ground (it was November by then), and those that didn’t rot got chilling damage that prevented them ever softening in cooking. Sweet potatoes that stay hard are no fun to eat!

Tomatoes are winding down. If a frost threatens we will harvest them all, including the green ones. I prefer to store them on egg trays or in shallow crates, to gradually ripen indoors. But other people prefer fried green tomatoes. To my taste buds, it could be cardboard inside the batter! I don’t know the nutrient content of fried green tomatoes, but I feel certain ripened tomatoes without batter are more nutritious!

Winter Squash harvest continues once a week throughout September and October. Stored winter squash can provide meals all winter and also in early spring when other crops are scarce. We used to harvest as late as possible in the fall, but now we prioritize getting a good cover crop established, to replenish and protect the soil, so we have a Grand Finale harvest just before Halloween, when we harvest all the large interesting almost-ripe squash, and give them away for lantern carving. Some go to the chickens too. Harvest before the fruits get frosted, which is shown by a water-soaked appearance of the skin.

Zucchini and summer squash are now being harvested every other day. Our last sowing was August 5. We harvest beyond the first fall frost, by covering that last planting with rowcover on chilly nights. But once it gets cooler, they grow slower, and are not worth checking every day.

From storage: spring cabbage, carrots, garlic and potatoes, winter squash.

Food processing is still busy.

Workhorse Crops Special Topic

Winter rye and crimson clover cover crop
Photo by McCune Porter

Cover Crops

September 17 is our last chance to sow oats as a cover crop. If sown later they will not reach a good size before they are killed by cold temperatures. The soil would not be held together well. It would be better in those circumstances to mow the weeds and leave their roots to hold the soil together over the winter.

Oats winter-kill in most of zone 7 or colder, and survive in zone 8 or warmer. The end for oats is around 10°F (-12°C), depending on their size and the frequency of cold temperatures. Large oat plants winter-kill after 3 days at 20°F (-7°C) or colder. Young oats are tolerant to temperatures down to 12°F (-11°C), until the 5 leaf stage, as the growing point is still underground. Once the plant starts to make noticeable vertical growth and form nodes (22-36 days after planting, depending on variety, sowing date, and water), oats can die at 24°F (-4°C).

Dead oats leave an easy-to-work surface for early spring vegetables.

Clovers can be sown here throughout September, as can winter wheat and winter barley. Winter rye can be sown here in September (not August – it could head up!). Hardy Austrian winter peas can be sown in late September with rye.

For more details, see my post Planning Winter Cover Crops

Controlling Aphids in Early Spring

 

Young eggplant struggling against lots of aphids.
Photo Pam Dawling

Controlling Aphids in Early Spring

Aphids can get out of control in early spring as they become active before their native predators, such as ladybugs, emerge from hibernation. We have a particular problem in our hoophouse and in our greenhouse on the eggplant, pepper and tomato transplants from mid-April to mid- to late-May depending when we manage to get them under control.We’re planning now, so we can be ready next spring.

There are many kinds of aphids. The lifecycle of aphids starts in spring with eggs hatching into wingless females that give birth via parthenogenesis to more females. Within a week, one female can produce 100 clones, which can repeat the process at the age of one week.  This continues until adverse weather or predators trigger production of a generation of winged female aphids that moves to new plants. Later in summer male aphids are born and females lay fertilized eggs that overwinter on host plants, to hatch the following spring.

Climate change is making the problem worse: for every 1degree Celsius rise in average temperature (about 2 F degrees), aphids become active two weeks earlier.

Newly planted insectary circle of flowers to attract beneficial insects.
Photo Pam Dawling

Organic Integrated Pest Management

I have a blog post about our organic integrated pest management, a step-by-step method of pest management which starts with actions least harmful to the ecosystem, only employing biological controls such as botanical sprays and selective pesticides if necessary after all other steps have been insufficient.

I recommend the ATTRA online publication Organic Integrated Pest Management. Each of the 22 pages is a poster, complete with good photos and concise clear info. Extension.org has an article on Organic Integrated Pest Management that explains how to  tackle pest problems one step at a time with ecologically-based practices, starting with actions chosen to reduce the chances of the pest ever getting a grip on your crops.

Steps in Organic Integrated Pest Management:

  1. Prevent infestation: Cultivate a good environment for your crops: healthy soil, sufficient space, nutrients and water, suitable temperature, soil pH. Practice crop rotation to reduce the chances of pests and diseases carrying over from one crop to the next. Clear old crops promptly, so they don’t act as a breeding ground for the pest. Choose suitable varieties that resist the pests you most expect.
  2. Cover or protect the plants physically from the pests (mulches to stop soil-dwelling pests moving up into your crops, netting, rowcover, planting diverse crops, and even growing trap crops)
  3. Provide habitat for natural enemies and other beneficial insects
  4. Monitor crops regularly at least once a week and identify any pests you see.
  5. Introduce natural enemies of the pest (bacteria, fungi, insect predators or parasites)
  6. Hand pick and kill the pests if the pest population is above the action threshold. Many fruit and root crop plants can take 30% defoliation before any loss of yield. Where the crop is the foliage, this may be too much!
  7. Use biological controls (often derived from natural enemies) if the damage is still economically significant after trying the earlier steps in the process.
A pepper leaf with tiny aphids.
Photo Pam Dawling

 Applying these principles to dealing with early spring aphids

1.      Prevent infestation If you act before the aphids arrive, you can use a fine mesh netting to keep them off your plants, but monitor to make sure no aphids have got inside the net. Control ants (which farm aphids for their sweet excretions). Reputed repellents that I have not tried: dilute garlic, onion or chilies with water; diatomaceous earth (health hazard from inhaling gritty particles); vegetable oils.

2.      Cover or protect physically. You could try trap crops of nasturtiums to draw aphids away from your crop, but how much of your space do you want to devote to nasturtiums, and how do you deal with them then? The same choices as on food crops.

3.      Provide habitat for natural enemies. Plant for a continuous supply of insect-attracting blooms, that flower early in the year and attract aphid predators such as ladybugs, lacewings, syrphid flies (hoverflies), damsel bugs, big-eyed bugs, and spiders. Grow some early blooming flowers with pollen and nectar they can use as alternative foods. Sow seed in fall for earliest bloom.

Native annuals are some of the earliest bloomers that attract beneficial insects:

Tidy Tips (Layia platyglossa), a spring flowering wild annual in the aster (sunflower) family. The white tipped yellow daisy like flowers are 2” (5 cm) across. A native of California, it grows up to 2ft (60 cm) tall. The seeds attract birds. Flowers have special value to native bees. Tolerates cold to -5°F (-20°C). Likes full sun. Seed is widely available. To start indoors, sow seeds 6 to 8 weeks prior to planting outside. Do not cover; seeds need light to germinate. Seeds germinate in 8-12 days at 65-70° F (18-21°C). Temperatures above 70°F (21°C) inhibit germination.

Information from Laura Blodgett in the Daily Improvisations blog, Southwest Idaho: Starting Tidy Tips from seed in February was too early. The seeds sprouted within a few days. The plants were sturdy from the start. It was too cold to plant them out, but they had so much growth that they were cramped in their small pots. There were enough warm days in March to harden them off, even though temperatures got down in the mid 30’s F (1-3°C) a few nights.

Meadowfoam (Limnanthes douglasii) commonly known as poached egg plant and Douglas’ meadowfoam. The five-petalled 1” (2.5 cm) flowers have yellow centers and white edges. A fast-growing bushy annual, very attractive to hoverflies, butterflies and bees. Requires insect pollination. It grows 6-12” (15-30 cm) tall and wide. Hardy to zone 2. Germinate below 60°F (16°C) (in fall?). May need light for germination. Easy to transplant, but don’t let it dry out! If spring-sown, may not flower until early summer (too late for aphid control). Temperatures below 55°F (13°C) will hinder flower opening as well as honey bee flight.

Baby blue eyes (Nemophila menziesii) is a low spreading, shrub-like plant with succulent stems and flowers with six curved blue petals. It grows 6-12” (15-31 cm.) high and wide. You can expect baby blue eyes flowers in late winter where temperatures are moderate and the plant blooms until late spring to early summer. Wait until soils warm to nearly 60°F (16°C) to sow seeds. Sow shallowly, about 1/16 inch (2 mm) deep. Baby blue eyes flower will germinate in 7-10 days with cool weather and short days. Baby blue eyes self-seeds readily but does not transplant easily. Butterflies, bees, and other helpful insects use the nectar as food. Pinch the tips of the growth to force bushier plant formation. Once the plant has flowered and seed heads formed, cut them off and dry them in a paper bag. Shake the bag after a week and then pick out the larger pieces of chaff. Transplant carefully 6-8 weeks after sowing. Sow in the fall, (but not frost-hardy? winter hardy in zone 7 and warmer?) then blooms from early spring to mid-summer. Baby blue eyes will die out if too hot in summer. Water frequently, provide shade (without hindering insects!)

Borage attracts many beneficial insects.
Photo Raddysh Acorn

Other annuals:

Borage is a warm-season annual, fast at producing nectar, taking about 8 weeks to flower from sowing. Borage grows 1-3 feet (30-90 cm) tall and wide; it blooms from early summer until the first frost in fall. Borage can be started indoors 6-8 weeks before the last frost. Seeds germinate in 7-10 days. Transplant borage seedlings outdoors after the last spring frost. Be careful when transplanting not to damage the taproot. Seeds can also be sown in the fall and will germinate the following spring.

Sweet Alyssum is a great insectary plant for aphid predators.
Photo Raddysh Acorn

Alyssum is a small plant we have used in broccoli and cabbage beds to attract beneficial insects. Sweet alyssum attracts three main groups of predatory beneficial insects a) Minute pirate bugs (they eat aphids, thrips, mites, psyllids, and insect eggs), b) Parasitic wasps (they lay eggs in aphids, beetles, flies, moths, sawflies, mealy bugs, and scales. The larvae hatch and eat their way out, killing the host. c) Hover flies, aka syrphid flies (the larvae feed on aphids). Alyssum flowers also attract butterflies and bees. Buy Sweet Alyssum, not the ornamental cultivars.

Shungiku, Chrysanthemum Greens, Chopsuey Greens, Glebionis Coronaria, is in the aster family, Asteraceae. It is native to the Mediterranean and East Asia. The plant’s greens are used in many Asian cuisines.  Shungiku is easy to grow and the leaves, young shoots and stems can be eaten. Leaves are aromatic, with a strong flavor. Some describe the taste as between celery and carrots. Even the petals and seeds can be eaten. Small House Farm grows this (and sells seed). Bevin says it does attract bees, butterflies and predatory insects. It would probably do well in the winter hoophouse, and could be provoked into bolting early in the spring.

Shungiku chrysanthemum greens.
Photo Small House Farm

Biennials:

Dill is a biennial umbellifera, often grown as an annual. It is easy to grow, germinating in 10-14 days. It doesn’t transplant easily (although we do it every year without a problem). It does self-seed readily, so to prevent this, cut the seed heads before the seeds turn tan. The leggy plant grows 2-4 ft tall (60-120 cm) and half as wide. Each plant grows only one hollow stem with an umbrella-shaped flower head from mid-summer to fall (too late for spring aphid predators). Dill tolerates cold and heat, but will likely die back to the ground after the first hard freeze. It might not be the easiest to include in a hoophouse.

Angelica is a biennial that can flower in the spring of its second year.

Perennials:

Phacelia.
Photo Territorial Seeds

Phacelia is a particularly useful perennial plant in early spring if it has overwintered as it is an early pollen source for bees coming out of hibernation. Sow in the fall for early spring blooms – Phacelia will survive mild frosts to bloom in spring. It winter-kills at approximately 18˚F (-8˚C). The seeds need darkness to germinate, and then the plants like to grow in full sun. Phacelia flowers from 6-8 weeks from spring sowing for a period of 6-8 weeks with lavender blooms that attract syrphid flies, bumblebees, honeybees and native bees, and also aphid predators like hoverflies and parasitic wasps. It can grow 6-40” (8-100 cm) tall, given the chance.

Yarrow is a perennial, hardy to zone 5. Common Yarrow (with flowers that range from white to red) is hardy down to zone 3. It attracts an array of beneficial insects. In addition, the scent of yarrow repels deer and mosquitoes.

Fennel, Foeniculum vulgare (common fennel), is an herbaceous perennial commonly grown as a summer annual. 5-7 ft (1.5-2 m) tall; each stem branches near the top and each branch ends with a flat-topped cluster of small yellow flowers; fennel looks very much like dill but is taller and coarser. Fennel blooms from mid-summer to frost. Too late and too tall for our goal of attracting spring aphid predators in the hoophouse.

Coyote bush, (Baccharis pilularis), also called chaparral broom, is a native shrub related to sunflowers. It may be a low-growing shrub or an erect tall bush, depending upon its growing conditions, and so may not be a good candidate for a potted plant in the hoophouse! It attracts syrphid flies, as well as bees and butterflies, with its abundant winter bloom.

Dandelions. If you decide to trust to weeds to feed your beneficial insects, take care about how much seed they sow!

4.      Monitor crops at least once a week

5.      Introduce natural enemies: We do have an aphid parasite in the hoophouse as we do find mummies, but not enough to control an aphid outbreak in spring. Parasitic wasps for aphids include

Aphidus colemani eggs hatch into larvae which feed on the nymphs from the inside, the nymph swells and hardens into a leathery, grey or brown colored mummy similarly to effects of Aphelinus abdominalis. Once larvae mature, adult A. colemani wasps chew their way out of the aphid mummy and emerge to seek out aphids. These parasites are a good choice for year-round use (in greenhouses and outdoors) as the short days of winter do not affect them. Optimum Conditions: 70-77°F (21-25°C), 80% relative humidity. Release rates: 500-3,000 per acre, 2-3 times at one week intervals, depending on the extent of infestation. This product controls aphids, especially melon and cotton aphids Aphis gossypii, but also attack green peach aphid Myzus persicae, tobacco aphid Myzus nicotianae and bird cherry-oat aphids Rhopalosiphum padi. Price $243 for three batches of 500, including overnight shipping, from Arbico Organics.

Aphidus ervi will consume all types of larger aphids, especially the potato aphid, Macrosiphum euphorbiae, and the glasshouse potato aphid, Aulacorthum solani. It also parasitizes Myzus persicae var. nicotianae, as well as aphids such as Sitobion sp., Schizaphis sp., Rhodobium sp., Acyrthosiphon pisum and others. Use Aphidius ervi especially when aphid infestations are just beginning, as control will be easier to achieve before the aphid population’s explosion. Aphidius ervi are shipped in a 125 ml bottle that contains at least 250 mummies and adult aphid parasites. The bottle has a ventilated cap for optimum humidity. A sugar-water feeder ring ensures adult survival. Release the emerged adults within 18 hours of receipt.  The parasitized aphid swells and hardens into a leathery, grey or brown colored mummy. The first mummies can be seen in the crop approximately 2 weeks after the first introduction. Use at the rate of 1 adult per 20-100 sq ft (1 per 2-9 m2) for preventative use. 250 mummies is sufficient for 5000-25,000 sq ft (460-2300 m2). Dose rate may be increased 5-fold for hot spots. Introduce A. ervi weekly for at least 3 weeks. Cost from Arbico is $101 including shipping each time, $303 likely. Monitor weekly and make further introductions as required. When pruning leaves, check for parasitized aphids (brown mummies) and if present, keep these leaves in the greenhouse until new parasites emerge. Because they fly as soon as they emerge, you need to cover doors and windows with mesh screens.

Another option is a predatory gall-midge, Aphidoletes aphidomyza, the larvae of which hunt and kill aphids. Kills over 60 species of aphids, especially those in greenhouses and hoophouses, including green peach aphid Myzus persicae; and  the hemlock woolly adelgid Adelges tsuga. Optimum conditions: 64-77°F (17-25°C) with RH of 70%. Shipped as pupae. The adults hatch within 1-12 days. After hatching, females lay eggs among aphid colonies. The eggs develop into larvae, and seek out adult aphids, injecting a toxin in their legs to paralyze them. Then they bite a hole in their thorax and suck out the body contents. Use 1 predator per 10 sq ft (1 m2), 2-3 predators per 10 sq ft (1 m2) for heavier infestations or 4,500 per acre (0.4 hectare) weekly until infestation subsides. 1000 for a 96x30ft (29×9 m) hoophouse, cost $125 including shipping per week, perhaps $375 total.

Lifecycle of the Green Lacewing
Photo J.K. Clark

Green Lacewing adults feed on nectar, pollen, and aphid honeydew, and the larvae are active predators of soft-bodied insect pests: aphids, thrips, whitefly, leafhoppers, spider mites (especially red mites) and mealybugs. After hatching, green lacewing larvae seek out prey – pest eggs, nymphs or adults. They feed for 2-3 weeks, spin a cocoon, and emerge as adults 10-14 days later. Lacewings have the ability to tolerate wide temperature ranges and work well with most other beneficial insects. Green Lacewing Eggs: Best low-cost biological control for common garden pests. If you want to establish Green Lacewings at the beginning of the season or have a limited infestation, choose the appropriate numbers of eggs for your garden or greenhouse. It takes 3-10 days for larvae to emerge depending on the temperature and other environmental conditions. Repeat applications every 1-2 weeks. Green lacewing eggs are available in loose media or on hanging cards for easy release. Green Lacewing Larvae: Best for immediate treatment of a pest problem. If you have a more severe infestation, buy the larval frames or bottles, which provide the quickest means to control unwanted pests – the larvae arrive ready to feed. Adult Green Lacewings: Best for establishing a population. If you are treating a large area and want to create a stable population, buy adult lacewings. The adults come ready to lay eggs throughout the release area. They do not actively control pests themselves. Cost 1000 eggs on cards $30 each time; 1000 larvae $61 each time; 100 adults $85. All prices include shipping.

A ladybug on the leaf stem of a sunflower planted to attract beneficials.
Photo Pam Dawling

Ladybugs. live ladybugs are best used when pest numbers are low, but can be used to fight existing infestations. Ladybugs primarily feed on aphids, but will prey on a variety of other pests including mealybugs, thrips, soft scale, whiteflies and spider mites. Each adult can consume up to 5,000 aphids in a lifetime. The larvae eat 50-60 aphids per day. Optimum Temperatures: 62-88°F (15-31°C). Ladybugs are prone to flying away. Help keep them around and attract native species by planting perennial and annual flowering plants and by avoiding chemical sprays. Create shaded areas or plants with dense canopies to provide alternative habitat when conditions are not ideal. While these methods may not keep all the ladybugs on site, they should help. If you have had issues with ladybug flight, consider using Assassin Bugs or Green Lacewing instead. 4,500 for up to 2,500 sq ft (232 m2). Cost $20/1500 plus Overnight or 2nd Day Air shipping.

6.      Hand pick and kill the pests if the pest population is above the action threshold. Handpicking aphids is likely impossible, so blast them off the plants with a water jet from a hose. This may decrease the population enough for natural predators to begin control.

7.      Use biological controls. Failing success with the methods above, a soap spray can be effective, although aphid predators will also be harmed. We use 3 Tablespoons (15 ml) per gallon (3.8 l) of biodegradable Murphy’s Oil Soap, in a sequence of 3 sprayings 5 days apart. The soap needs to hit the aphids to kill them. Soak both sides of the leaves and directly spray any visible pests. Murphy’s Oil Soap is made from lye (potassium hydroxide) or sodium hydroxide, and vegetable oils with 2% of synthetic ingredients including trisodium MGDA, Lauramidopropyl dimethylamine oxide (a non-toxic purifying agent), sodium tallate. Official insecticidal soaps are made from potassium salts of fatty acids (potassium laurate).

Insecticidal soap works in several ways. The soap penetrates insects’ cuticles, which causes their cells to collapse and dry out. Soaps suffocate insects such as scale insects. Soap sprays are also somewhat effective against chiggers, earwigs, fleas, mites, scales, and thrips. They are not effective on chewing insects such as caterpillars and beetles.

You can make your own soap spray if you have some fragrance-free liquid soap. You do not need to include oil. Note that “dish soap” is actually detergent, not a soap at all, so don’t use that. Test your homemade spray on a small part of a plant first and wait 24 hours to see if there is any damage. Look for spotting, wrinkling, or browning of leaves. If you see any trouble, don’t use the spray.

Soap sprays can be potentially damaging to some plants. Crops that are susceptible to damage from soap sprays include cucumbers, squash, melons, beans, and peas.

Neem is a botanical insecticide effective against aphids.

Best Options for our Hoophouse in April and May

Looking at the options for dealing with aphids and choosing those most compatible with pot-grown plants to flower in spring in our greenhouse and hoophouse, these seem our best chances:

  • ·         Cultivate a good environment for our crops.
  • ·         Monitor crops regularly once a week.
  • ·         Grow Meadowfoam from seed in the hoophouse in late October. Hardy to zone 2. Try February too.
  • ·         Grow Tidy Tips from seed in the greenhouse in February, pot up and move into the hoophouse just before flowering. Try starting some in late October too. Tolerates cold to -5°F
  • Grow Sweet Alyssum from seed started in February.
  • Grow borage form seed started in February. Move pots to hoophouse after April 1.
  • Grow perennial phacelia started in October and February for future years. Phacelia will survive mild frosts to bloom in spring. Protect from worse than “mild frosts”.
  • Grow yarrow from seed started in October and February. It is hardy down to zone 3.
  • Grow Shungiku from seed sown in late September, and provoked into bolting early in spring.
  • If we want to spend $100+ to deal with a bad infestation, buy 3 units of ladybugs.

Winter-Kill Temperatures of Cold-Hardy Vegetables 2021

Our pond iced over.
Photo Ezra Freeman

Winter-Kill Temperatures of Cold-Hardy Vegetables 2021

I keep records of how well our crops do in the colder season, both outdoors and in our double-layer hoophouse. I note each increasingly cold minimum temperature and when the various crops die of cold, to fine-tune our planning for next year. We are in zone 7a, with an average annual minimum temperature of 0-5°F (-18°C to -15°C).

The winter 2020-2021 was mild, with our lowest temperature being a single late January night at 10°F (-12°C). We had one night at 11°F (-12°C) one at 17°F (-8°C), three at 18°F (-8°C also) and one at 19°F (-7°C). very little snow or ice. Similar to temperatures in the 2019-2020 winter.

The winter of 2018-2019 had lowest temperatures of 6°F (-14°C) in late January 2019, 8°F (-13°C) in December 2018 and a couple of 11°F (-12°C). In early January 2018, we had some extremely cold temperatures of -8°F and -9°F (-22°C and -23°C). Averaging our winter low over those four winters 2017-2021 gives 4.8°F (-15°C), within the zone 7a range.

Georgia Cabbage Collards, good down to 20F (-7C) Photo Southern Exposure Seed Exchange

New Info this winter

I’ve added in some temperatures for collard varieties (Georgia Cabbage collards, McCormack’s Green Glaze, variegated collards) from the Heirloom Collards Project, and also gained some info on spinach (Long Standing Bloomsdale), kales (Rainbow Mix Lacinato) and mustards (Chinese Thick-Stem) from Southern Exposure Seed Exchange. I’ve added in their suggestions on cold-tolerant early spring lettuces, Crawford, Simpson Elite, Susan’s Red Bibb and Swordleaf.

My results from other years still hold up.

Swordleaf lettuce on the right with another lettuce and radishes in spring.
Photo Bridget Aleshire

Using the List

Unless otherwise stated, these are killing temperatures of crops outdoors without any rowcover. All greens do a lot better with protection against cold drying winds. Note that repeated cold temperatures can kill crops that can survive a single dip to a low temperature, and that cold winds, or cold wet weather can destroy plants quicker than simple cold. Crops get more damage when the weather switches suddenly from warm to cold. If the temperature drops 5 or more Fahrenheit degrees (about 3 C degrees) from recent temperatures, there can be cold damage. The weatherman in Raleigh, NC says it needs 3 hours at the critical temperature to do damage. Your own experience with your soils, microclimates and rain levels may lead you to use different temperatures in your crop planning.

Reflect spinach in the open got damaged but not killed at -9F.
Photo Pam Dawling

Outdoor killing temperatures of crops (unprotected unless stated)

35°F (2°C):  Basil.

32°F (0°C):  Bush beans, some cauliflower curds, corn, cowpeas, cucumbers, eggplant, limas, melons, okra, some pak choy, peanuts, peppers, potato vines, squash vines, sweet potato vines, tomatoes.

27°F (-3°C): Many cabbage varieties, Sugarloaf chicory (takes only light frosts).

25°F (-4°C): Some cabbage, chervil, Belgian Witloof chicory roots for chicons, and hearts, Chinese Napa cabbage (Blues), dill (Fernleaf), some fava beans (Windsor), annual fennel, some mustards (Red Giant, Southern Curled) and Asian greens (Maruba Santoh, mizuna, most pak choy, Tokyo Bekana), onion scallions (some are much more hardy), radicchio, rhubarb stems and leaves.

22°F (-6°C): Some arugula (some varieties are hardier), Bright Lights chard, endive (Escarole may be a little more frost-hardy than Frisée), large leaves of lettuce (protected hearts and small plants will survive colder temperatures).

20°F (-7°C): Some beets (Bulls Blood, Chioggia,), broccoli heads (maybe OK to 15°F (-9.5°C)), some Brussels sprouts, some cabbages (the insides may still be good even if the outer leaves are damaged), some cauliflower varieties, celeriac, celtuce (stem lettuce), some collards (Georgia Cabbage Collards, variegated collards), some head lettuce, some mustards/Asian greens (Tendergreen, Tyfon Holland greens), flat leaf parsley, radicchio (both Treviso and Chioggia), radishes (Cherry Belle), most turnips (Noir d’Hiver is the most cold-tolerant variety).

Large oat plants will get serious cold damage. Oats seedlings die at 17°F (-8°C)

Canadian (spring) field peas are hardy to 10-20°F (-12 to -7°C).

Ruby chard, good down to 15°F (-9.5°C). hardier than Bright Lights, but less hardy than green chard varieties.
Photo Kathryn Simmons

15°F (-9.5°C): Some beets (Albina Verduna, Lutz Winterkeeper), beet leaves, some broccoli and cauliflower leaves, some cabbage (Kaitlin, Tribute), covered celery (Ventura), red chard, cilantro, fava beans (Aquadulce Claudia), Red Russian and White Russian kales, kohlrabi, some lettuce, especially medium-sized plants with 4-10 leaves (Marvel of Four Seasons, Olga, Rouge d’hiver, Tango, Winter Density), curly leaf parsley, rutabagas (American Purple Top Yellow, Laurentian), broad leaf sorrel, most covered turnips, winter cress.

12°F (-11°C): Some beets (Cylindra,), some broccoli perhaps, some Brussels sprouts, some cabbage (January King, Savoy types), carrots (Danvers, Oxheart), most collards, some fava beans (mostly cover crop varieties), garlic tops if fairly large, Koji greens, most fall or summer varieties of leeks (Lincoln, King Richard), large tops of potato onions, covered rutabagas, some turnips (Purple Top).

10°F (-12°C): Covered beets, Purple Sprouting broccoli for spring harvest, a few cabbages (Deadon), chard (green chard is hardier than multi-colored types), some collards (Morris Heading can survive at least one night at 10°F), Belle Isle upland cress, some endive (Perfect, President), young Bronze fennel, Blue Ridge kale, probably Komatsuna, some leeks (American Flag (Broad London), Jaune du Poiteau), some covered lettuce (Pirat, Red Salad Bowl, Salad Bowl, Sylvesta, Winter Marvel), Chinese Thick-Stem Mustard may survive down to 6°F (-14°C), covered winter radish (Daikon, China Rose, Shunkyo Semi-Long survive 10°F/-12°C), Senposai leaves (the core of the plant may survive 8°F/-13°C), large leaves of savoyed spinach (more hardy than smooth-leafed varieties), Tatsoi, Yukina Savoy.

Oats cover crop of a medium size die around 10°F (-12°C). Large oat plants will die completely at 6°F (-17°C) or even milder than that.

Garlic shoots poking through the mulch in January. Survive down to 5°F (-15°C), and if killed, will regrow from underground.
Photo Pam Dawling

5°F (-15°C): Garlic tops even if small, some kale (Winterbor, Westland Winter), some leeks (Bulgarian Giant, Laura), some bulb onions, potato onions and other multiplier onions, smaller leaves of savoy spinach and broad leaf sorrel. Many of the Even’ Star Ice Bred greens varieties and the Ice-Bred White Egg turnip are hardy down to 6°F (-14°C), a few unprotected lettuces if small (Winter Marvel, Tango, North Pole, Green Forest).

0°F (-18°C): Chives, some collards (Blue Max, Winner, McCormack’s Green Glaze), corn salad (mâche), garlic, horseradish, Jerusalem artichokes, Even’ Star Ice-Bred Smooth Leaf kale, a few leeks (Alaska, Durabel, Tadorna); some bulb onions, yellow potato onions, some onion scallions, (Evergreen Winter Hardy White, White Lisbon), parsnips (probably even colder), salad burnet, salsify (?), some spinach (Bloomsdale Savoy, Long Standing Bloomsdale,  Olympia). Walla Walla onions sown in late summer are said to be hardy down to -10°F (-23°C), but I don’t trust below 0°F (-18°C)

Crimson clover is hardy down to 0°F (-18°C) or perhaps as cold as -10°F (-23°C)

-5°F (-19°C): Leaves of overwintering varieties of cauliflower, Vates kale survives although some leaves may be too damaged to use. Lacinato Rainbow Mix kale may survive this temperature.

A cover crop mix of winter rye, hairy vetch and crimson clover.
Credit Kathryn Simmons

-10°F (-23°C) Austrian Winter Field Peas and Crimson clover (used as cover crops).

-15°F (-26°C) Hairy vetch cover crop – some say down to -30°F (-34°C)

-20°F (-29°C) Dutch White clover cover crops – or even -30°F (-34°C)

-30°F to -40°F (-34°C to -40°C): Narrow leaf sorrel, Claytonia and some cabbage are said to be hardy in zone 3. I have no personal experience of this.

-40°F (-40°C) Winter wheat and winter rye (cover crops).

Hoophouse Notes

Winter crops snug in our hoophouse in a December snowstorm.
Photo Pam Dawling

Our double-plastic hoophouse keeps night time temperatures about 8F (4.5C) degrees warmer than outdoors, sometimes 10F (5.5C) degrees warmer. Plus, plants tolerate lower temperatures inside a hoophouse. The soil stays warmer; the plants recover in the warmer daytime conditions (it seems to be the night+day average temperature that counts);

In the hoophouse (8F (4.5C) degrees warmer than outside) plants without extra rowcover can survive 14F (7.7C) degrees colder than they could survive outside; with thick rowcover (1.25oz Typar/Xavan) at least 21F (11.6C) degrees colder than outside.

For example, salad greens in our hoophouse can survive nights with outdoor lows of 14°F          (-10°C). Russian kales, lettuce, mizuna, senposai, spinach, tatsoi, turnips, Yukina Savoy survived a hoophouse temperature of 10.4°F (-12°C) without rowcover, -2.2°F (-19°C) with. Bright Lights chard got frozen leaf stems.

Lettuce Notes

Lettuce varieties for a solar-heated winter greenhouse or hoophouse in zone 7a: (hardiest are in bold) Buckley, Ezrilla, Green Forest, Green Star, Hampton, Hyper Red Rumpled Wave, Marvel of Four Seasons, Merlot, New Red Fire, North Pole, Oscarde, Outredgeous, Pirat, Red Cross, Red Sails, Red Salad Bowl, Red Tinged Winter, Revolution, Rouge d’Hiver, Salad Bowl, Sylvesta, Tango, Winter Marvel, Winter Wonderland.

Cold-tolerant early spring lettuces include Buckley, Crawford, Green Forest, Hampton, Merlot, New Red Fire, Revolution, Simpson Elite, Susan’s Red Bibb and Swordleaf.

Notes on Chicories and Endives

Verona Red radicchio, hardy to about 20°F (-7°C).
Photo Southern Exposure Seed Exchange

Chicories and endives fall into two groups, but they are confusing because the common names sometimes suggest the opposite group than they are botanically. Here’s the best info I have.

Cichorium intybus, commonly called chicories, are mostly heading crops. The group includes radicchio, both Treviso and Chioggia – hardy to about 20°F (-7°C). Belgian Witloof endive (the kind for forcing chicons) is also a chicory. It dies at 25°F (-4°C). Sugarloaf chicory is the least hardy chicory, and dies at 27°F (-3°C).

Cichorium endivia, commonly called endives, are mostly loose-leaf crops, less cold-hardy than intybus types (chicories). This group includes Frisée types and escaroles, which are also known as Batavian endives. They generally survive down to 22°F (-6°C), although Perfect and President endives can survive down to 10°F (-12°C) – can anyone confirm or deny this?

© Pam Dawling 2021


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It consists of eight video presentations, most of which come with pdf handouts. My contribution is Growing Asian Greens, and pairs nicely with Guide to Asian Vegetables with Wendy Kiang-Spray, author of The Chinese Kitchen Garden: Growing Techniques and Family Recipes from a Classic Cuisine. Other topics include Dandelion Wine, Homemade Teas, Food Conversations, Passive Solar Greenhouse Design, Productive Growing from Home, and Growing Your Own Spices.

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