Category: Root Crops

Vegetable Storage Tips

Our winter squash storage cage. Photo Twin Oaks Community

Key factors to consider when selecting vegetables for long-term storage

  • Most storable vegetables are roots or tubers.
  • Winter squash, onions and garlic are the main exceptions.
  • And tree fruits such as apples and pears.
  • There are hard-headed storage cabbages too, but those varieties are getting harder to find, as fewer people grow for storage. Search the seed catalogs for the word “storage”. Other varieties are for fresh market, or processing, and won’t store for long.
  • Don’t plan to grow a specific crop unless you have the right kind of place to store it!
  • You also need a likely market. I love celeriac, but it’s not widely known, so I wouldn’t recommend growing lots until you have an idea of the demand.
  • Choose varieties that are sturdy and chunky, not slender carrots, for instance. (Shriveling is related to the ratio of volume to surface area.)
  • Ideally, practice that variety on a small scale the year before growing a very large amount, to see how it does in your soil.
  • If it’s too late to do that, try three different varieties and keep records of how they do.
  • Read the small print in the seed catalogs! Moschata winter squashes such as butternuts. Long Island Cheese and Seminole store all winter, but acorn squash do not. You can store acorn squash for a couple of months, but then move them along to people’s dinner plates.

Harvesting tips to maximize the storage life of stored vegetables

Carrot harvest cart
Photo Mari Korsbrekke
  • Storing vegetables is very much a Garbage In-Garbage Out type of thing. If you put unsound vegetables into storage, they will rot and the rot could spread.
  • Good storability starts with good growing techniques
  • During growth, fend off any serious pest predation, as crops with holes in may not store well.
  • Be sure you know the temperature at which each crop will suffer cold damage, and get it harvested before that happens.
  • Harvest when the crops are optimum size and in peak condition.
  • Ideally, harvest in dry weather.
  • Handle the vegetables gently. Bruises can happen invisibly, so if you drop something, don’t store it.
  • White potatoes can reach a storable state two weeks after the tops die in the field. If you are in a hurry, mow the tops off, then wait two weeks. Check that the skins are “set” and don’t tear, if you rub the potato with your thumb.

    Sweet potato harvest crates
    Photo Nina Gentle
  • Trim leafy tops from root vegetables, leaving very short stems on beets and carrots. During long storage, the stubs of the leaf stems may die and drop off, but this is nothing to worry about.
  • If you cut the tops off beets completely, the red color will wash out during cooking. Definitely don’t cut into the root part of beets when trimming. Some people trim the long ends of beet roots, but I never have. They don’t take up much space!
  • I do trim the roots from kohrabi, and for that task, I do cut into the bulbous part of the root, as the skinny root has such a high concentration of fibers that it’s like a steel cable! The cut surface soon heals over.
  • Look each vegetable over and only store ones without soft spots or deep holes. Carrots or sweet potatoes snapped in half can heal over and store just fine, but stabbed potatoes won’t. Superficial bug bites will heal over but not tunneling.
  • Small roots won’t store well. We have a “training tool” for new crew members which is a bucket lid with holes cut in it. If the carrot can pass through the carrot hole, it’s too thin to store well. Potatoes less than about an inch are not worth storing. Likewise tiny turnips.

    Bucket lid with holes for sorting root vegetables for storage.
    Photo Wren Vile
  • For traditional storage without refrigeration, most roots store best unwashed (less wrinkling). This can make them harder to clean later.
  • If you are going to store root crops unwashed, consider setting them in a single layer on the field and making a second trip round to pick them up into crates when the skins are dry. If you are going to wash them, the opposite is true! Get them into water before the skins dry, to help the washing go quicker. We don’t wash sweet potatoes, white potatoes or squash. We do wash all the other root crops, as it’s harder to get them really clean if the soil dries on them. Provided you store them in humid enough conditions, they will not shrivel.
  • Some crops need curing before storing (alliums, peanuts, sweet potatoes, white potatoes).
  • Tops of garlic and onions can be trimmed after the crops have cured and the leaves died. Making braids or ropes of alliums with their tops on can be a profitable option.

The best storage conditions for different types of vegetables

Crates of potatoes in our root cellar.
Photo Nina Gentle
  • In my book, Sustainable Market Farming, I have a whole chapter on Winter Vegetable Storage.
  • Growers have only good things to say about the CoolBot system from Store-It-Cold. Basically you build a well-insulated space (shed, room, truck body), buy a window AC unit and the CoolBot and follow their excellent instructions to install the device which lets you run the AC at a lower temperature, like a refrigerator, at a fraction of the cost.
  • Hang a thermometer in your storage spaces, so you know when to warm or cool them. Digital thermometers might measure humidity too.
  • You can get a small electronic device that will send an alert to your phone if the temperature goes too far out of range.
  • For storing white potatoes without refrigerators, the best place is a root cellar. You are aiming for cool and moist conditions: 40-50°F (5-10°C), with 85-90% humidity. You really don’t want to store potatoes below that range, or they go black when you make fries.
  • Most other vegetables fit into four other sets of storage conditions:

A. Cold and Moist (33-40°F/1-4°C, 95-100% humidity, works for most root crops, and also cabbage, Chinese cabbage, kohlrabi and leeks.

B. Cool and Moist is mostly potatoes, as I already mentioned. Pears, apples and cabbage also store well in these conditions but not sharing space with potatoes! More on that later.

C. Cool and Dry is for garlic and onions. 32-40°F/0-4°C and 60-70% humidity. It’s also possible to store alliums warm and dry at first, 65-85°F/18-30°C, but definitely not 40-56°F (4-13°C) for garlic, or 45-55°F (7-13°C) for bulb onions or they will sprout. Never warm after cold either.

D. Warm and Dry to Fairly Moist is for winter squash and sweet potatoes. Never below 50°F (10°C). Ideal temperature 55-59°F (13-15°C). Temperatures above 65°F (18°C) hasten sprouting. Also ripening green tomatoes like 55-70F/13-21C and moist (75-85%).

  • For the warmer options, barns or basements might be suitable in the fall, before they get too cold.
  • If you are planning a new barn, consider installing an insulated basement to be a root cellar.
  • There are traditional in-ground storage methods, such as clamps, pits and trenches. The easiest version of this, in the right climate, is to mulch heavily with about 12″ (30 cm) of insulation (such as straw, dry leaves, chopped corn stalks, or wood shavings) over the row, and maybe add low tunnels over the mulch.

    In-ground vegetable storage Drawing from WSU
  • Clamps are made by setting down a layer of insulation on the ground, piling up the crops in a rounded cone or ridge shape, covering thickly with straw, then working round the mound digging a ditch and slapping the soil up on the mound.
Vegetable storage clamp.
Drawing from WSU
  • Pits and trenches start by digging a hole, lining it with straw or an old chest freezer, layering in the vegetables with straw and covering with boards and a thick layer of insulation. Insulated boxes stored in unheated areas need 6-8″ (15-20 cm) of insulation on the bottom, sides, and top.
  • This all takes a lot of work, so look into the CoolBot idea first!

Suitable containers for storing vegetables

  • We use perforated clear plastic sacks for roots, cabbages and kohlrabi. They reduce the water losses that lead to wrinkling.;
  • We use net bags for onions and garlic; plastic milk crates for potatoes;
  • We use folding plastic crates for squash and sweet potatoes.
  • We leave horseradish, Jerusalem artichokes and leeks in the ground here in zone 7a, but we don’t get frozen soil for much of the winter.
  • We don’t use any packaging materials, but in England in the past I stored roots in boxes of damp peat moss, sawdust, sand or wood ash. I find it better to get the right storage conditions for the vegetables, rather than try to insulate them in their crates.
  • Set the containers on pallets, not directly on concrete floors, to reduce condensation.
  • When stacking your containers, allow gaps along the walls and between stacks, for airflow. Celeriac needs more ventilation than beets or kohlrabi, for instance.
  • Sometimes night ventilation offers cooler drier air than you can get in the daytime.

Vegetables that have particular needs for long-term storage

Sweet Potatoes in storage.
Photo Pam Dawling
  • Sweet potatoes must be cured before storage. This means hot humid conditions until the skins don’t rub off when you rub two together. After that you can move them to storage conditions (or turn down the heater and humidifier!)
  • It is important that sweet potatoes never go below 50°F (10°C) or they will suffer a permanent chilling injury that makes them almost impossible to cook. I know because I’ve made that mistake, leaving them in the ground too long, hoping they’d grow bigger.
  • White potatoes also need to cure until the skins toughen, in moist air (90% humidity) for 1-2 weeks at 60-75°F (15-24°C). Wounds in the skin will not heal below 50°F (10°C).
  • We sort our potatoes after two weeks of curing and find that sorting at this point usually reduces the chance of rot so that we don’t need to sort again.
  • They need to stay moist so they don’t wrinkle. They have fairly exacting temperature requirements so they don’t sprout.
  • Remember to keep white potatoes in the dark while curing as well as during storage.
Home vegetable storage options, from WSU
  • Some vegetables exude ethylene in storage: fruits, damaged produce, sprouting vegetables. Some crops are not much affected by ethylene (greens for example) and can be stored in the same space with ripening tomatoes, for instance.
  • Other vegetables are very sensitive to ethylene, and will deteriorate in a high-ethylene environment. Potatoes will sprout, ripe fruits will go over the top, carrots lose their sweetness and become bitter.
  • When storing ripe fruit, ventilate with fresh air frequently, maybe even daily, to reduce the rate of over-ripening and rotting.
  • Ethylene also hastens the opening of flower buds and the senescence of open flowers.
  • Alliums like it drier than most crops. Heed my warning about the “danger zone” sprouting temperatures. Not 40-56°F (4-13°C) for garlic, or 45-55°F (7-13°C) for bulb onions or they will sprout.

Tips for extending the storage life of vegetables

  • For non-refrigerated storage, unless using outdoor pits or clamps, several smaller containers of each crop are often a safer bet than one giant one, in case rot sets in.
  • For crops that store best at 32°F (0°C), if you can only store them in warmer temperatures (up to 50°F/10°C), provided they do have high humidity, you can expect to get about half the storage life they’d last for in ideal conditions.
  • After you’ve put your produce into storage, don’t completely forget about it! Keep a record of what is stored where and perhaps a check sheet for inspection. Monitor the rate of use and notice if you’d benefit from more or less of each crop next winter.
  • Regularly check the storage conditions are still meeting your goal, and check thorough the crops at least once a month, removing the bad ones. Shallow crates make this easier.
  • For root crops and squash, and maybe alliums, the initial storage period is the most likely to show up trouble. Later the crops become more dormant and less change happens.
  • Keeping root cellar temperatures within a narrow range takes human intervention, or sophisticated thermostats and vents.
  • If needed, electric fans can be used to force air through a building.
  • Make a realistic assessment of how long your crop will last in the actual conditions you are providing, and plan to move them all on before then.
  • You may be able to reallocate crops to some colder spaces as some of the original produce stored there gets used.
  • After long storage, some vegetables look less than delicious, and benefit from a bit of attention before the diners get them. Cabbages can have the outer leaves removed, and can then be greened up by exposing to light for a week at 50°F (10°C). This isn’t just cosmetic – the vitamin C content increases ten-fold. Carrots can lose their sweetness over time, unless frequently exposed to fresh air, by ventilating well.
Storage #4 green cabbage. The name says it all.
Fedco Seeds

How cold can leafy greens and salad crops survive?

Our hoophouse beds after the nights at 2F (-17C) and 8F (-13C). Looking amazing! Pam Dawling

We were luckier with the weather than many people over the weekend (12/23-12/26/2022). And so were our vegetable crops. On Friday 12/23 we prepared for a suddenly very cold night. It was very windy as we battled to stop the hoophouse windows from blowing open. We finally got some shims, a hammer and a stepladder, and wedged them closed. They stayed that way until Tuesday 12/27. We were fortunate in getting no precipitation (I hate ice!) and no power outage.

Pool noodles repurposed as draft excluders.
Pam Dawling

We fortified the doors with our rock collecting buckets, and prevented most of the under-door drafts with our pool noodle draft excluders. They have a rope running through them, which is hooked onto small cup-hooks on the door frame. We repurposed noodles that had been used as props at a party or some other kind of event. They had been covered in tube socks and had glued-on googly eyes.

Rolls of rowcover at the ready in our hoophouse.
Pam Dawling

It was a bit unnerving being in the hoophouse as it creaked and groaned in the wind. In the winter we keep rolls of rowcover ready for any night we think will be below 8F (-13C). We unrolled the rowcovers by lunchtime and laid tools on the ends nearest the doors. I was worried that if we lost power, and therefore the inflation, it would get very cold indeed in the hoophouse.

The DIY manometer in our hoophouse. (the background lines have faded). Pam Dawling

Since we last changed the plastic we haven’t managed to get the recommended 1/3” (8.5mm) pressure difference in the “bubble” between the plastic layers, compared to our normal air pressure. Mostly we don’t even get ¼” (6.5mm). The “bubble” provides thermal insulation as well as physical strength against snow or ice buildup, and strong winds.

It got down to 2F (-17C) outdoors Friday night, and Saturday didn’t warm up much. I don’t actually know what the night temperature was in the hoophouse as our recorded low temperatures don’t make sense: 14F (-10C) for four consecutive nights (Fri to Mon). I suspect we didn’t reset the thermometer correctly. Usually the hoophouse can hold 8 F (4.5 C) degrees warmer than outdoors, but not 12 F (7 C). It looks like it did, perhaps because we didn’t open it all day!

Soil thermometer in our hoophouse on 27 December 2022.
Pam Dawling

The soil is still nice and warm in there: 59F (15C). That really helps. The rowcovers are usually removed in the daytime, either pulled aside if we expect to need them again the next night, or rolled up out of the way. Most of the time they stay rolled up at the east end of the hoophouse. We appreciate not needing to deal with rowcovers most of the time! On Saturday 24th, the temperature maximum for the day outdoors was 24F (-4.5C), and we kept the rowcovers in place over the crops. On Sunday the high outdoors was 28F (-2C) so we pulled the rowcovers aside until the night. On Monday 26th the night-time forecast was benign enough that we rolled the rowcovers up. And now we get a milder spell.

Hakurei turnips with frozen yellow leaves where they touched the plastic (rowcover protected the plants). Pam Dawling

How did the crops fare? It’s not always obvious at first if a crop has been killed by cold or not, But I can now say with confidence that nothing died. The edge beds are always the coldest. The south edge bed had Hakurei turnips, delicious and notoriously the least cold-hardy turnip variety. Most of the globe of the turnip sits on the surface of the soil. You can see in the photo that some of the leaves, the ones right by the wall plastic, have been killed and turned yellow. But the roots themselves (with rowcover over them) seem fine.

Bright Lights chard with cold-damaged stems in our hoophouse north edge bed after nights at 2F and 8F
Pam Dawling

Over the other side, in the north bed, we have some Bright Lights chard, among other things. Multi-colored chards are less cold-hardy than red ones, which in turn are less cold-hardy than green ones. We know we take a risk in growing Bright Lights through the winter, but we so enjoy the sight of the short pieces of colored stems in our salad mixes that we take the risk. Some of the stems have curled over, probably on their way to dying, but the plants live on, to provide many more salads this winter! And some cooked greens too.

Some of the giant senposai leaves, where not fully protected by the relatively narrow rowcover, have developed tan dead spots, so those leaves can just continue as the plants’ solar panels until we get tired of looking at them and decide they are no longer needed.

Each winter I update my Winter-Kill Temperatures of Cold-Hardy Vegetables list, except this past spring I had nothing new to add. Outdoors, I noticed today that the tatsoi has definitely died, the Vates kale and the spinach have survived (uncovered) and the small garlic leaves don’t seem troubled. The leftover lettuce transplants have been damaged, if not killed.

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.

More About Winter Vegetable Storage

 

Bucket of freshly harvested Detroit Dark Red beets for storage.
Photo Pam Dawling

 See my previous posts

Here I will tell you more about storage of various crops.

  • Storing crops maximizes their season of availability
  • Many crops can be stored without electricity, perhaps in buildings that serve other uses at the height of the growing season.
  • The Washington State University Extension publication, Storing Vegetables and Fruits at Home, is a good introduction to alternatives to refrigerated storage, using pits, clamps and root cellars. Drawings below are from WSU Storing Vegetables and Fruits at Home
  • There is also good information in old versions of the USDA Agriculture Handbook 66.
  • Some vegetables need to cure before storage in different conditions from those needed for storage. Curing allows skins to harden and some of the starches to convert to sugars.
A storage cabbage, with curled-back leaf on the head, showing maturity.
Photo Bridget Aleshire

Four Sets of Vegetable Storage Conditions

See the chart in my book Sustainable Market Farming, for more details.

By providing storage spaces with just 4 types of conditions, at least 25 crops can be stored.

A= Cold and Moist: 32°F–40°F (0°C–5°C), 80%–95% humidity — refrigerator or winter root cellar conditions. Most roots, greens, leeks. Use ventilated crates, or perforated plastic bags (or mesh net bags for cabbages) indoors. If above 45°F (7°C), roots will start to sprout. Greens benefit from light. See more about root cellars below. Roots can be stored in clamps or pits outdoors – more on those options below.

B= Cool and Fairly Moist: 40°F–50°F (5°C–10°C), 85%–90% humidity — root cellar. Potatoes. Use ventilated crates. Keep in darkness to prevent greening. See the links to my potato storage info.

Trimming garlic stems prior to long-term storage.
Photo by Brittany Lewis

C= Cool and Dry: 32°F–50°F (0°C–10°C), 60%–70% humidity — cooler basements and barns. Garlic and onions. Use net bags or shallow racks. Avoid temperatures of 40°F-56°F (4°C-13°C), or they will sprout. Also avoid reversals of temperature (warm conditions after cold ones). Newer info says 32°F-40°F (0°C-4.5°C). is best for garlic.

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

D= Warm and Dry to Fairly Moist: 50°F–60°F (10°C–15°C), 60%–70% humidity — basements. Sweet potatoes and winter squash. Use shallow racks or perforated trays. Sweet potatoes need curing at higher temperatures and humidity before storing.

The entrance to our root cellar.Photo Twin Oaks Community

Root Cellars

  • Potatoes can be stored for five to eight months with a good in-ground root cellar.
  • Potatoes are best stored in a moist, completely dark cellar, at 40°F (5°C) to 50°F (10°C). Ventilate as needed for air exchange and to keep the cellar in the ideal temperature range.
  • Also for apples, cabbage, or root vegetables, but be careful what you mix, because ethylene from the apples, for example, will cause potatoes to sprout!
  • Some people pack unwashed vegetables in boxes of sand, wood ash, sawdust or wood chips. Perforated plastic bags are a modern alternative.
  • Cabbages or pepper plants can be hung upside down in the cellar to ripen, or simply to store.
  • Celery and leeks can be replanted side by side in tubs of soil.
  • See Nancy and Mike Bubel’s book Root Cellaring to learn how to design, build and use a root cellar.
Using a sturdy digging fork to harvest leeks in December.
Photo Pam Dawling

In-Ground Storage

  • Depending on your winter temperatures, some cold-hardy root crops (such as turnips, rutabagas, carrots, parsnips, Jerusalem artichokes and horseradish) and also leeks can be left in place in the ground, with about a foot (30 cm) of insulation (such as straw, dry leaves, chopped corn stalks, or wood shavings) added after the soil temperature drops to “refrigerator temperatures.”
  • Hooped rowcovers or polyethylene low tunnels can keep the worst of the weather off.
  • There could be some losses to rodents, so experiment on a small scale the first winter to see what works for you.
  • Besides being used as a method for storage of hardy crops deep into winter, this can be a useful method of season extension into early winter for less hardy crops such as beets, celery and cabbage, which would not survive all-winter storage this way.
  • In colder regions plan to remove the crops before the soil becomes frozen, or else wait for a thaw.

Drawing credit WSU Storing Vegetables and Fruits at Home

Harvested turnips ready for storage.
Photo Pam Dawling

Storage Clamps (Mounds)

  • Cabbage, kohlrabi, turnips, rutabagas, carrots, parsnips, horseradish, Jerusalem artichokes, salsify and winter radishes can be stored with no electricity use at all, by making temporary insulated outdoor storage mounds (clamps).
  • Mark out a circular or oval pad of soil, lay down some straw or other insulation, pile the roots up in a rounded cone or ridge shape, and cover them with straw and then with soil, making a drainage ditch round the pile. As a chimney for ventilation, leave a tuft of straw poking out the center. Slap the soil in place to protect the straw and shed rainwater.
  • For the back-yarder, various roots can be mixed, or sections of the clamp can be for different crops. Those growing on a large scale would probably want a separate clamp for each crop. It is possible to open one end of a clamp or pit, remove some vegetables, then reseal it, although it takes some care for it to be successful.
  • There is a balance to be found between the thermal buffering of one large clamp and the reduced risk of rot that numerous smaller clamps provide.

Drawing credit WSU Storing Vegetables and Fruits at Home

 Pits and Trenches

  • Dig a hole in the ground, line it with straw, lay in the vegetables, then cover with more straw and soil.
  • To deter rodents, bury large bins such as metal trash cans, layer the vegetables inside with straw, and cover the lid with a mound of more insulation and soil.
  • Trenches can have sidewalls made with boards to extend the height.
  • You can bury insulated boxes in the ground inside a dirt-floored shed or breezeway. Insulated boxes stored in unheated areas need six to eight inches (15–20 cm) of insulation on the bottom, sides and top.

Drawing credit WSU Storing Vegetables and Fruits at Home

Cherokee Purple tomatoes. Don’t store ripening tomatoes with your potatoes!
Photo Southern Exposure Seed Exchange

Ethylene

  • Ethylene is associated with ripening, sprouting and rotting.
  • Some crops produce ethylene in storage — apples, cantaloupes, ripening tomatoes all produce higher than average amounts.
  • Chilling, wounding and pathogen attack can all cause damaged crops to produce ethylene.
  • Some crops, including most cut greens, are not sensitive to ethylene and can be stored in the same space as ethylene-producing crops.
  • Other crops are very sensitive and will deteriorate in a high-ethylene environment. Potatoes will sprout, ripe fruits will go over the top, carrots lose their sweetness and become bitter.

 

Drawing credit WSU Storing Vegetables and Fruits at Home

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

Root Crops in April – the Hungry Gap

Young Cylindra beets in early May.
Photo Pam Dawling

Root Crops to Plant in Central Virginia in April

We are in cold-hardiness zone 7a, with an average last frost of 4/29. Those in other climate zones can study our Root Crops in May or Root Crops in March for information more useful in their area.

Outdoors we can sow  carrots #4 & #5, parsnips, radishes #2, (last date 4/15, sow on the shoulders of a newly transplanted lettuce bed to save space), beets (last date 4/15, hand sown or with an EarthWay seeder Chard plate, 2 or 3 passes. 1 cup sows 360 ft/110m)

Here we can plant potatoes anytime in April.

It is too late for us to sow any root crops in the hoophouse. (Besides, we want tomatoes!)

Having good stored crops like these beets will feed you through the Hungry Gap.
Photo Pam Dawling

Root Crops to Harvest in Central Virginia in April

As in January, February and March in central Virginia, in most of April there are still no roots to harvest outdoors except overwintered parsnips and maybe carrots, Jerusalem artichokes and horseradish.  Radishes from the first outdoor sowing will be ready at the end of April. We can usually harvest radishes until the end of May. Our hoophouse radishes usually finish in early April. By then it is hot and any remaining radishes bolt.

From storage, if we still have them, we can eat beets, carrots, celeriac, kohlrabi, parsnips, potatoes, rutabagas, sweet potatoes, and turnips.

This is the Hungry Gap (see Special Topic for April below)

Colorado Potato beetle late stage larva
Photo Pam Dawling

Other Root Crop Tasks in Central Virginia in April

  • If you are growing your own sweet potato slips, cut 6-12” (15-30cm) slips daily and stand them in water. Once a week, plant rooted slips in 4” (10cm) flats.
  • Hill up potatoes when 6” (15cm) high. Cover half the vine. Repeat after 2 weeks. This deals well with weeds and gives the potatoes more soil to grow into.
  • Potato beetles: Use Spinosad [or Neem] once larvae are seen, if there are more than 50 adults/50 plants or more than 200 larvae/100 plants. If you have fewer, you can leave them alone. Spinosad: Spray when bees are not flying (early morning or late evening.) Shake well, 1-4 Tbsp/gall (1fl.oz=2Tbsp=30ml.) Approx 8-30 ml per liter. Repeat in 6 days. Clean and triple rinse the sprayer. Do not flush Spinosad into creeks or ponds.
  • Thin and weed carrots.
  • Mow cover crop mixes in late vegetable plots when rye or wheat heads up, to help legumes develop.
  • Take rowcover from turnips that were sown 3 or more weeks earlier, to use on newer and more tender crops.
  • Till beds you’ll plant in a week or two, as heavy rain may prevent tilling close to sowing time. My ideal is to till as deep as needed ahead of time, then do a superficial tilling or scuffle hoeing the day before planting. This gives the best weed control.
  • Spread compost on beds you’ll plant in 3 weeks or so, and till in the compost when the soil is not too wet, not too dry.
  • If exposed to 10 consecutive days below 45°F (7°C), celeriac will bolt.
  • Store spring and fall seeds (spinach, peas, beets) in a cool place for the summer.
Vates kale outdoors. An oleracea type, Vates is very cold-hardy.
Photo by Nina Gentle

Special Root Crop Topic for April in Central Virginia: the Hungry Gap

What is the Hungry Gap?

The Hungry Gap happens in temperate climates with four seasons. In winter the short day-length reduces plant growth, and when it’s cold, maybe damp, windy, and overcast, the rate of crop growth drops further. The Hungry Gap is the annual period of the shortfall in local fruit and vegetables. April is the leanest month of the year in northern temperate climates, and the period can extend from January to May. This may be a factor in the origin of the 40 days of Lent.

Spring is not the time of overflowing bounty you might expect – leaves are growing, but not much else. Depending on your particular climate, there may be some vegetables that are winter-hardy. Almost every vegetable lover yearns for more variety than that!

In the spring, any remaining winter vegetables are getting ready to bolt (produce flowers and seeds rather than more leaves). Growers and gardeners are enthusiastically sowing and transplanting new crops, but planting too early would be a sad mistake and it takes time before those new crops can be harvested. That gap between the last of the winter crops and the first of the early spring crops, is called the Hungry Gap.

It’s not a familiar term these days, because importing produce from warmer climates hides the reality. Vegetable consumption in much of the Western hemisphere has shifted from Medieval (leaves and roots) to Mediterranean (“ratatouille vegetables” and salads). Importing or long-distance hauling demands more energy usage, as does the refrigeration they often require in transit.

Also there has been a practice of growing vegetables with artificial heat and light. This is not ecological, as use of fossil fuels contributes to climate change. The food sector accounts for 30% of global energy consumption and produces about 20% of GHG emissions (see the 2011 FAO report). Most of this energy consumption comes from oil and gas in the form of artificial fertilizers and pesticides, on-farm machinery and food processing.

Sweet Potatoes in storage.
Photo Pam Dawling
Sustainable Ways to Bridge the Hungry Gap

How did people survive the hungry gap in times gone by, and what can we learn from those strategies? Eating in the hungry gap used to be both hard and uninspiring – a restricted diet with few options. Adding options involves advance planning and advance work.

  1. Use stored food, such as root crops, winter squash and pumpkins
  2. Preserve fruits and vegetables from other seasons. Consider jams, pickles, canning in jars, freezing, drying, salting and fermenting (think sauerkraut)
  3. Grow more winter-hardy crops that start regrowth early in the spring, and may be harvestable during the winter. Consider covering the rows with rowcover or polyethylene low tunnels.
  4. Grow more perennial crops, such as asparagus, rhubarb, sea kale and sea beet (Beta vulgaris subsp. Maritima, wild beet). Although they take several years to establish, they will then yield earlier in the year than crops grown from seed in spring. Asparagus and rhubarb provide new flavors early in the year and signal the change to come.

    Asparagus in early April.
    Credit Wren Vile
  5. Sow fast-growing cold-hardy crops as early as possible after the winter solstice, for example spring leafy vegetables such as spinach, kale, collards, fast cabbage varieties, and lettuce.
  6. Add crop protection in the form of rowcovers, low polyethylene tunnels (cloches), caterpillar tunnels, high tunnels (hoophouses, polytunnels) to create a warmer environment, trapping heat and humidity and warming up the soil, providing earlier harvests. Protect early sowings of quick crops, like radishes, arugula, land cress, salad greens, and also the first few weeks of newly planted kale, collards, spinach, mizuna, pak choy).
  7. Forage sustainably for edible wild greens as a spring ‘tonic’, even if not a major item in your diet. The strong flavors provide a welcome change after repetitive winter vegetables, and a useful top-up to the supply of produce as stores run low. Spring is one of the best seasons for foraging, but you do have to reliably identify what you’re picking, so get yourself a good guide book or phone app. Ramps, nettles, violets, chickweed, dandelion, garlic mustard, and lamb’s quarters are some of the many wild greens available in spring. See Rustic Farm Life: Wild Spring Greens You Should Be Eating

    Ruby chard.
    Photo Kathryn Simmons
  8. Maximize the number of annual and biennial crops you grow that are in season during the Hungry Gap. Some are mentioned already. Here are more ideas: chard, globe artichokes, herbs, Jerusalem artichokes, kale (one variety is called “Hungry Gap” because it crops during this period. It was introduced to UK agriculture during WWll in 1941), leeks. If your winter climate is mild enough (zone 8 or 9): over-wintered Purple sprouting broccoli, and spring greens (immature close-spaced dark-green cabbages).

    Brassica oleracea ‘Hungry Gap’ – kale
    Photo Chiltern Seeds, UK
  9. Indoor gardening. Grow sprouts and microgreens. These don’t take much advance planning and can perk up a winter or spring meal. Microgreens grow in compost or on special “blankets”, but sprouts are generally grown in jars or trays. Pea shoots are an easy one to start with, and you can use dried peas from the supermarket. When sprouting it is important that you buy organic seeds, to be sure that they have not been treated with any chemicals. Rinse your sprouts twice a day, and keep everything clean.

Read more about the Hungry Gap

https://www.youtube.com/watch?v=FbZfTAYDA88

https://theunconventionalgardener.com/blog/what-is-the-hungry-gap/

https://sustainablefoodtrust.org/articles/spring-plate-eating-hungry-gap/

https://www.farmdrop.com/blog/hungry-gap-seasonal-british-produce/

This is the last post in the monthly series on root crops. You can see them all here:

Root Crops in May

Root Crops in June

Root Crops in July

Root Crops in August

Root Crops in September

Root Crops in October

Root Crops in November

Root Crops in December

Root Crops in January

Root Crops in February

Root Crops in March

Workhorse Crops for the Month

Next month I will start a new monthly series. Workhorses are crops that are reliable under a wide range of conditions, including weather, soil, date and other variables. Some are easy to grow, some pump out lots of food, some are “insurance crops” like chard that stand in your garden until you need to harvest them. Part of my motivation for this series is to help all the “Covid-steaders” who started growing food during the pandemic and want to up their game without investing a lot more time. Part is to help established gardeners and growers who need to make a living while dealing with the changes the past year has brought to their markets and to our climate. We need some easier days!

 

Root Crops in March

We shovel many wheelbarrows full of compost to our raised beds every year.
Photo Wren Vile

Root Crops to Plant in Central Virginia in March

As soon as the soil is dry enough and not frozen, we spread compost on the raised beds we plan to plant in February and March, and till in the compost. We make ourselves a Spring Start-up Plan, so we know where to focus our energy when the weather gives us a chance.

Spring Start-up Plan

We aim to spread compost 4-6 weeks before planting, rototill 2-4 weeks before planting, and prep the bed a week or two before. This is more time than we allow later in the year, but in early spring it’s good to seize the opportunities that arise and not take the weather for granted.

This means in January we compost and till beds for spinach, turnips and our first carrots. In the first half of February we till the turnip beds and any beds of winter-killed oats cover crops that we will be planting soon. We compost the first lettuce bed, the kale and collard beds, and those for cabbage, beets, more carrots, senposai and peas (all have planting dates March 9 to 15). In the second half of February, we compost the third carrot bed and till the ones we already composted. In early March we till the third carrot bed.

A bed ready for tilling after mowing the cover crop and spreading compost.
Photo Pam Dawling

Once we get to March, day length has increased and temperatures are starting to climb. There is a noticeable increase in the rate of germination and growth (unlike for our February sowings, which are rooted in faith and optimism!) All being well with the weather (it’s extremely wet this year!), in early March, we direct sow turnips (3/6- 3/16), and radishes #1 (Cherry Belle or some other fast variety)

In mid-March, we can transplant kohlrabi. And we direct sow carrots #3 and beets. See below for more about beets. In late March, we direct sow our carrots #4, and more radishes and beets. We can sow kohlrabi if we have no transplants, and thin to 6” (15 cm) later.

Potatoes

A row of potato seed pieces ready to cover.
Photo by Wren Vile

We plant potatoes when the daffodils bloom, usually mid-March. Last year I wrote an extensive series of posts about growing potatoes.

See Planning to Grow Potatoes Again, the last part of a monthly series on growing potatoes, a dietary staple.

PART ONE: Planting potatoes (April)

PART TWO: Growing potatoes (May)

PART THREE: Potato pests and diseases (June)

PART FOUR: Harvesting potatoes (July)

PART FIVE: Storing potatoes (August)

PART SIX: Planning to grow potatoes again (September)

Beets

Detroit Dark Red beets in early June sunshine.
Photo Pam Dawling

Beets are workhorse root crops that thrive in mild weather, store well, and are popular traditional foods. They are crops that can provide high yields for the time invested.

Beets come in several types, round, top-shaped and long. The size and quality of the greens is a factor if you sell bunched beets with tops, or use the tops for greens. We like the 6” (15cm) long Cylindra/Formanova/Forono ones (55 days to maturity, OP). They are very tender and easy to cut into regular slices, for pickles or cooking. The skins come off easily, and the flavor is very sweet and the texture tender.

Among round ones we like Ace (50 days to maturity, F1 hybrid), and Detroit Dark Red (60d), a tender open-pollinated variety. Detroit Crimson Globe is said to maintain better flavor in hot weather than most others, which can develop off-flavors. Early Wonder Tall Top (48d), is also open-pollinated. Lutz Green Leaf (70d) is a big long-storage variety. There are also golden beets, white beets and candy-striped Chioggia beets, although in my experience, what they gain in appearance they lose in flavor and tenderness.

Beets seeds average 35,000 /lb. 2,200/oz, 80 seeds/gm. 1,285 seeds (2/3 oz, 18gm) sow 100’ (30m).  150’/oz, 2,300’/lb., 9 lbs/acre. 315,000 seeds/acre. Yield can be 40 lbs. (18kg) greens, 100 lbs. (45kg) roots/100’ (30m), or 14,000 lbs/acre, 2540 kg/ha.

Beets need a pH of 6.0-7.0, preferring 6.5-6.8.  They require abundant potassium, which can be supplied by woodash. Boron deficiency can show up in beets as internal browning, or dark dead tissue, as well as distorted leaf growth. It is most likely to occur in alkaline soils after long hot, dry spells. Beets can suffer from “zoning,” (white rings in the roots), if there are acute weather fluctuations.

Young Cylindra beets in early May.
Photo Pam Dawling

Sow beets whenever the soil is between 50°F (10°C) and 95°F (35°C), so long as you can keep the surface damp. With beets we do a single sowing in mid-March and more in early August. We are growing for fresh use, pickling and storage, but not bunch sales, so we don’t need to do frequent sowings. For a continuous supply of greens and baby beets, sow every 2 weeks from spring until 8 weeks before regular frosts usually occur, or about 10 weeks before a heavy freeze is expected.

We direct sow either dry beet seed, or some we have presoaked for 1-2 hours. Beet seed drowns easily: don’t use too much water or soak for too long.  Sow 0.5″(1.2cm) deep in spring, deeper in hot summers, but never more than an inch (2.5cm) deep. We sow an inch (2.5 cm) apart in single rows 8-10” (20-25cm) apart. Others sow in bands 2-4″ (5-10cm) wide, at about 15 seeds/ft (2cm apart), with bands 12-18″ (30-45cm) apart. As for carrots, avoid soil crusting.

It is important to get good soil contact for the corky seedballs, so tamp or roll the rows after seeding. Keep the rows damp, by watering as needed for the 5-17 days they take to emerge. Beet seeds are actually seed balls (clusters of seeds) so each one you plant will produce several seedlings right next to each other. “Singling” the beets is an important step, and they will benefit from hoeing, thinning and weeding. Beets deal with weed pressure and crowding a lot better than carrots do, so if you have to choose which to weed, the carrots win! We thin in stages, so that at the second thinning, the baby beets can be used as a crop.

Detroit Dark Red beets , harvested, washed and trimmed.
Photo Pam Dawling

For mature beets, allow each a minimum of 3” (7.5cm). The Cylindra beets can be left a bit closer, and will push themselves up out of the soil as they grow. Know and Grow Vegetables recommends establishing 5 plants per square foot (54 per square metre) for early beets. This translates to a final spacing of 4 x 7” (10 x 18cm). For maincrop beets, aim for 10-15 per square foot (107-161 per square metre.) For maximum total yields of small sized roots use a spacing of 1 x 12” (2.5 x 30cm).

This info about growing beets is excerpted from my book Sustainable Market Farming. See the book for more on pests and diseases, harvesting and storing, and seed saving.

In our climate, beets are one of the crops that can be sown in spring and again in early fall (actually August for beets here in central Virginia). See my August post Sowing beets, radishes and kale, transplanting cabbage.

See Root Crops in August for more about fall beets. Beets can be tricky to germinate in hot weather, but to get good storable-sized roots, we need to get them established by 8/20. (Two months before our average first frost.)

Root Crops to Harvest in Central Virginia in March

From storage, if we still have them, we can eat beets, carrots, celeriac, kohlrabi, parsnips, potatoes, rutabagas, sweet potatoes, and turnips.

As in January and February in central Virginia, there are no roots to harvest outdoors in March except parsnips, Jerusalem artichokes and horseradish. We do have horseradish, but not the others, but we don’t have a lot of demand for that.

We have had outdoor night temperatures of 12°F/-11°C and 11°F/-13°C. This winter we had some carrots outdoors over the winter. We harvested them and got 150 pounds from 400 row feet. Not a high yield but they do taste good! They are Danvers 126. The intended sowing date was August 14, but we didn’t get the seed in the ground until September 5.

A crate of overwintered Danvers 126 carrots

In the hoophouse our #4 radishes will get harvested during March. Our #5 radishes, sown 12/23, will then feed us until around April 7.

We still have some of our good size second hoophouse turnips until mid-March. We sowed those on October 25. The greens are a bit ragged now and less appetizing for cooking, although on cold rainy days, they make for more pleasant harvesting than any greens outdoors! Turnip greens (and Russian kale) are our last hoophouse greens to bolt, so we value them.  We need to harvest the turnips to make space to transplant our hoophouse tomatoes in mid-March.

Other Root Crop Tasks in Central Virginia in March

  • Green chit (pre-sprout) seed potatoes, see Planting potatoes .
  • Buy seed potatoes for June planting, and refrigerate them. Keep at 40-50°F (4.5-10°C) in the dark, until 6/1.
  •  Test and condition sweet potatoes for 2 to 4 weeks at 75-85°F (24-29°C), 95% humidity if you are planning to grow your own sweet potato slips.
Sweet potato sprouting slips.
Photo Pam Dawling

Special Root Crop Topic for March in Central Virginia: What makes vegetable crops bolt?

Green mizuna bolting in our hoophouse in mid April. Although the mizuna is bolting, the Scarlet Frills is hanging in there.
Photo Pam Dawling
  • Bolting is the term for plants going to seed. Rather than grow more leaves and bigger roots, the plants develop stems, skinnier and fewer leaves, then flower buds, flowers and seeds.
  •  The plants are switching their energy to survival of the species in the face of unsuitable conditions.
  •   When a plant starts to bolt, it is usually a sign to expect a poor harvest. It is also an indication that the plant will decline in terms of flavor. Lettuce become bitter. As long as you can harvest leaves or roots that are not too woody, you can eat bolting plants. But they do become too tough and inedible at some point.
  •  Crops inclined to bolt include arugula, basil, beets, brassicas (such as cabbage), carrots, celery, leeks, lettuce, onions, turnips and spinach.
  •  Bolting is initiated by plant hormones called gibberellins.
  •  Although bolting is usually seen on crops approaching maturity, it is initiated much earlier.
  •  It’s a complex business, understanding the various triggers to bolting.
  •  Stress factors, including changes in day length (usually an increase), high temperatures or low temperatures at particular stages in a plant’s growth cycle, plant size, plant type, root stress, and stresses such as insufficient water or minerals.
  • Increased day length: Bolting can happen when day length increases as summer approaches. This can be a problem if you planted your seeds too late in the spring. The extra hours of light trigger annual plants to run to seed.
  •  High soil temperatures: As soil temperatures increase in summer, plants are triggered to begin seed and flower production. This isn’t a problem late in the crop’s life, after bountiful harvests. But, when spring has unusually hot weather or if you plant crops too late into the growing season, your crop may bolt before any harvests. Cool weather crops like lettuce and spinach will bolt in spells of hot dry weather.
  • Cold temperatures: A sudden cold snap in spring can signal to biennials (such as onions, leeks, beets and carrots) that “winter” has happened and it’s time to develop seeds for the next season. If you start these crops too early in the calendar year, you risk exposing young plants to cold weather, priming the plants to develop flower stems as soon as the weather warms up again. 
  •  Plant size:
  •  Annual plants grow from seed, flower and set seed all in one year. That can be spring to winter or fall to summer. Annual crops are sensitive to daylength, and will start making flowers as the daylength (and temperature) increase. When an annual plant bolts, it’s the beginning of the end.
  • Biennial plants (onions, leeks, carrots, beets, and chard) grow big the first year, then seed the second year. They can initiate flowers in the first yea, due to unsettled weather early in the season. Bolting usually occurs after a prolonged cold spell, often during an immature stage. Cold nights, hot days and late frosts may also contribute to premature flowering.
  • Root stress: Bolting caused by root stress typically happens when you disturb a plant’s root system by transplanting, or if your plant runs out of growing space in a container that’s too small.
  • Stresses such as insufficient minerals or water: Healthy soil with plenty of nutrients and balanced moisture levels will encourage quick growth. Every grower should aim for this balance, especially those in hotter climates where it’s a race to plant leafy salads, cooking greens and root crops before the hot weather fights against you.

Collards bolting in late March.
Photo Pam Dawling

Next week I will provide information on avoiding, preventing and postponing bolting.

Flame Weeding

Commiseration and sympathy to ice-blasted farmers and gardeners

Visits to my website shot up over the weekend. People are checking out my Winter-Kill Temperatures of Cold-Hardy Vegetables as they are dealing with temperatures considerably colder than they ever expected for their region.  I hope you can find some helpful information there while you triage your crops into “OK with these temperatures, can be left alone”/”might die, need help”/”will definitely die, no point in trying to save them”.

Q and A

Next a couple of questions that people left on the contact form, that I thought others might be interested in.

Q1. Is there an easy way to figure out what vegetables I can plant to maximize my space and yield. I am not sure if its my soil or sunlight availability in my backyard garden.

A. Most vegetables do need at least 6 hours a day of sunlight, so as we get closer to spring, assess various spots in your backyard. Maximizing use of the space includes careful choice of plant spacing, but also following one crop with another, or squeezing crops in between others. There’s no quick answer. Search my site for Succession Planting, Crop Spacing, Choosing Crops.

Q2. I am currently looking for Onion seeds or seedlings to purchase for approximately 1hector to plant. We based in the Free State Area.

A. South Africa? Sorry, I have no idea what is available where you are. 1 hectare is a huge area for onions, especially if you have never grown them before. Use transplants, not direct-seeded onions. Choose varieties adapted to your latitude, or else they may never grow big, or may not dry down and store well.

Flaming can be used for weed control, pest control, or crop termination.

Flame weeding can be used for carrots and beets before emergence.
Photo Brittany Lewis

Our introduction to flame-weeding was via the first article I ever read in Growing for Market magazine. It was about flaming for pre-emergence weed control in carrots. It sounded like such an effective method that we bought a Red Dragon flamer and never looked back! I remember saying and writing that it worked so well it felt like cheating!

Our flamer

We use a handheld flamer attached to a propane cylinder that is in a wheelbarrow pushed by a second person behind the first. This person also acts as a “fire warden.” Some growers mount the propane on a backpack frame. Walking along the aisle between beds and wafting the wand diagonally back and forth across the bed takes about ten minutes for a 100′ (30 m) bed. Flame-weeding alone can reduce hand-weeding to one hour/100′ (30 m). Hand-weeding can be reduced to 6 minutes/100′ (30 m) by flame-weeding after using stale beds which have been hoed three or four times.

Stale seedbed flaming for weed control

In the stale seedbed technique, the bed is prepared and watered ahead of planting time and one or more flushes of weeds are germinated and flamed or hoed off. Flaming avoids bringing any new weed seeds to the surface. To sow large crop seeds into a seedbed that has already had the weeds removed (by flaming or other stale seedbed technique), you can use a stick seeder or easy-plant jab planter. Making furrows for small seeds will inevitably activate a few weed seeds along the rows.

Flame weeding, pre-emergence

Flame weeding a carrot bed.
Photo Kati Falger

Carrots, beets and parsnips are ideal crops for pre-emergence flame-weeding. They do very poorly with competition, and grow more slowly than weeds, consuming lots of time hoeing, cultivating and hand weeding to get good yields. Flame weeding can change all that, with pre-emergence either as part of a stale seedbed technique, or post-sowing.

The latter method is to prepare the bed, sow the seeds, water, and then monitor carefully. The day before you expect the carrots to emerge, flame across the whole surface of the bed. Use a soil thermometer and the table here to figure out which day to flame.

Table of vegetable seed germination as a function of soil temperature

 

Days to Germinate 50F (10C) 59F (15C) 68F (20C) 77F (25C) 86F (30C) 95F (35C)
Carrots 17.3 10.1 6.9 6.2 6.0 8.6
Beets 16.7 9.7 6.2 5.0 4.5 4.6
We sow “indicator beets” with our carrots so that we know when to flame-weed them
Photo Kathryn Simmons

People who use pre-emergence flame-weeding for carrots can use a few “indicator beet” seeds sown at one end of the bed to show when to flame. As soon as you see the red loops of the beet seedlings breaking the surface, flame the carrots. (But look for carrots too, just in case!) Beets are always a bit quicker than carrots in germinating. Note that beets are about half a day ahead of carrots at 50°F–68°F (10°C–20°C), but more than a day at 77°F–95°F (25°C–35°C). The challenge with carrots is to keep the soil surface damp until they come through. As an indicator for beet seeds, you can use a few radish seeds.

Another way to get an alarm call is to put a piece of glass over part of a row. The theory is that the soil under the glass will be warmer and the crop there will come up sooner than the rest. I tried this once, but the soil under the glass dried out, and those carrots came up later than the rest! Nowadays we have a “no glass in the garden” rule, for safety, so I use beets, the thermometer and the chart.

See the useful resource Flame Weeding for Vegetable Crops  from ATTRA

Flame-weeding growing crops

Potatoes can get impossible to hill when you’d like to if you have wet weather, and this is where flaming can save the day. Potatoes may be flamed at 6″–12″ (15–30 cm) tall, to kill weeds without damaging the potato plants. After that, flaming is not recommended.

Sweet corn can be flame-weeded after planting, either pre-emergence or, with care, after the crop is two inches (5 cm) tall, using a directed flame.

Onion and garlic crops can be flame-weeded when relatively mature. Flame-weeding can achieve as good results as hand-weeding using one-third of the labor. Flame-weeding can damage young plants (four or fewer leaves), so bide your time. Direct the flame at the base of the plants, in the morning, when the plants are turgid. This technique is for unmulched crops. Naturally, if you have used straw or hay mulch, flame-weeding is not such a smart idea!

Peanut seedlings can be slow to emerge, so pre-emergence flame-weeding may be helpful. The seedlings look somewhat like peas or clover. Because they grow slowly for the first 40 days, they will not thrive if you lose them in weeds (guess how I know?!).

Flaming for ending potato growth

Potato plants come to a natural end when the leaves die, after which no further growth can be induced in them. Once the tops die, the potato skins start to toughen up. If you are growing storage potatoes and are impatient for the end to come, you can mow off the tops or flame them, to start the skin-thickening process, which takes around two weeks. The potatoes are ready when you can rub two together without any obvious damage to the skins.

Flaming for pest control

Pest habitat includes all those half-wild edges and odd corners. You can reduce the pest count in these havens by mowing, hand weeding, or flaming. Be sure not to remove all the habitat for beneficial insects while you do this.

Colorado Potato beetle late stage larva
Photo Pam Dawling

Colorado potato beetles can be tackled by flaming while the potatoes are less than eight inches (20 cm) tall, as an effective pest control measure. It won’t kill the potato plants. Choose a warm sunny day when the pests are at the top of the plants. Flaming can kill 90 percent of the adults and 30 percent of the egg masses, according to ATTRA.

Harvesting from bean plants with bad bean beetle damage.
Photo Wren Vile

Mexican bean beetles can be killed by flaming after harvest for that planting is finished. Flaming will kill the plants too. We used to plant six or seven successions of beans, every two weeks, then flame the old plants when the pest count got too high, and move on to a newer planting. Nowadays we buy the Pediobius parasitic wasp to deal with the MBB, and we can sow beans less often and harvest them for longer.

Flaming trap crops

Young turnips (with flea beetles!) in need of thinning for cooking greens.
Photo Pam Dawling

Flea beetles can be lured by a row of mustard greens. They like the pungent compounds in brassicas. Once you have lured the flea beetles you need to deal with them before you create a flea beetle breeding ground. Flaming the mustard plants is one possibility.

Striped cucumber beetle in squash flower. Photo Pam Dawling

Cucumber beetles  have a preference for some particular squash varieties, which may be grown as a trap crop: Cocozelle summer squash, Seneca and Dark Green zucchini are all “cucumber beetle preferred”! When beetles accumulate in the trap crop, flame it or till it in.

Stink bugs: Russ Mizell has published a paper on trap cropping for native stink bugs in the South. He recommends buckwheat, triticale, sunflower, millet, field pea and sorghum. A succession of trap crops including these and others such as pumpkins, cowpeas and other small grains (which are most attractive in the milk or soft dough stage) could help. Flame the trap crops when the stink bug numbers in the trap crop build up.

Excerpted and adapted from Sustainable Market Farming

Repurposed stroller makes a fine flame weeder.
Photo Sustainable Harvest Farm Kentucky

Root Crops in February

 

Large Smooth Prague celeriac. (Currently sold out Feb 2021)
Photo Southern Exposure Seed Exchange

Root Crops to Plant in Central Virginia in February

We sow no root crops in our hoophouse in February. It’s too late for radishes or turnips. If you are in a place colder or darker than winter-hardiness subzone Zone 7a, with an average minimum temperature of 0° to 5° F (-18°C to -15°C), see Root Crops in January.

If the soil outdoors is dry enough and not frozen, we spread compost on the raised beds we plan to plant in February and March, and till in the compost. Root crops that we sow outdoors here in February include carrots #1 and turnips in mid-February, and carrots #2 and radishes in late February. It’s true not much growing happens in February, but it helps us if we are able to get some crops planted early, leaving us more capacity for other crops once those are in the ground. And if the soil isn’t dry enough, we just do those jobs as soon as we can. We would hate to miss an opportunity!

Carrot Bed Prep

One of our many carrot beds, looking good.
Photo Kathryn Simmons

Carrots do very poorly with competition from weeds or too many other carrots. You can make use of the Stale Seedbed Technique, preparing the bed ahead of time, and flaming or hoeing one or more flushes of weeds as they germinate. I’ll do a separate blogpost on flame-weeding soon, as I have too much info to squeeze in here. It works so well, it feels like cheating!

Carrots are small seeds, needing a fine tilth (small soil particle size and good texture – not likely to crust or blow away).  Good information on crop spacing for maximum yields, or biggest vegetables is in an out of print book, The Complete Know and Grow Vegetables by JKA Bleasdale, PJ Salter, and others. For maximum total yield of carrots, they recommend 1.5” x 6” (4 x 15cm). You get medium sized carrots. For early carrots go with 4 x 6” (10 x 15cm) to minimize competition and get rapid growth. If you want to have rows more than 6” (15cm) apart, calculate the area of these optimum spacings, then divide by your chosen row space. For example, if your rows are 12” (30cm) apart, the carrots can be as close as 0.75’ (2cm) if total yield is more important than individual size, or 2” (5cm) for fast early carrots. We do five rows in a 4 ft (1.2m) bed, so the rows are about 10” apart, with the outer rows 4” (10cm) from the bed edge.

Young Carrot Plants After Thinning. Photo Kathryn Simmons

Carrot Thinning and Weeding

Remember to thin carrots as soon as you can see them well enough to do so. We usually hoe between the rows first, then crawl along thinning and weeding. It does take time! But you won’t get good carrots without thinning, unless you either have a precision-seeder that drops one seed per inch, or pelleted seed which you can sow at one per inch. Precision seeders like the Jang are expensive, but worthwhile if you need to use it every week. Pelleted seed costs more than raw seed, and its big advantage is traded off for two other disadvantages: The soil has to be kept well-watered until germination or else the clay coating will imprison the seed forever, and the seed does not store for long – don’t keep any over for next year.

Greenhouse Root Crop Sowings for Transplants

The only root crops we ever transplant are celeriac and kohlrabi (a stem vegetable really, not a root). I have transplanted many things and I am skeptical of books saying this or that can’t be transplanted, but not beets or rutabagas, which I hear people transplant as soil blocks or plugs. So try it if you think it will help.

Celeriac

Flats of celeriac seedlings.
Photo Kathryn Simmons

We have grown both Diamante (100 days from transplanting) and Large Smooth Prague (110d), and strongly prefer Diamante, as it seems to us to be more tolerant of warm weather, less prone to rot, and easier to clean. Several growers say that Diamante and Brilliant are virtually indistinguishable.

This crop likes rich soil with lots of organic matter, some shade from mid-day and afternoon sun, and ample water without sitting in waterlogged soil. We make sure to choose beds in a shadier part of the garden. Celeriac can rot if too damp, so keep it weeded and remove some of the lower leaves to improve airflow. A pH 5.8-6.7 is ideal. Celeriac can benefit from seaweed as a foliar spray, or side-dressing with compost during the long growing season.

Celeriac requires long steady growth, and the challenge is to prevent checks to growth. The Virginia climate is on the warm side for celeriac, it prefers cooler areas, but we have good success if we pay attention at a few critical times. Celeriac can tolerate frost quite well, so there is no hurry to harvest in the fall.

Sow seeds 1/8″(3mm) deep, and keep the soil surface moist. The minimum germination temperature is 40°F/5°C, and the optimal range 59–70°F/15-21°C. Germination is slow, typically 14 to 21 days, and it takes 10-12 weeks to grow to transplant size, so start in plenty of time. We sow in open flats, then spot out (prick out) into deeper flats. We sow February 10, which is about 10 weeks before our last frost date. Celeriac can be sown from 67 days before the last frost date to 184 days before the first fall frost date, but you don’t get large roots unless you have plenty of growing time.. If your climate includes long chilly springs, I’d suggest starting 12 weeks before the last frost date.

Emergence takes at least 12 days at 59°F/15°C and 7 days at 68°F/20°C. The ideal temperature is 68°F/20°C day, and 59°F/15°C at night. The fluctuating temperatures, with nights cooler than days by 9°F/5°C, help speed germination. Another factor when choosing germination temperature to aim for, is that at 59°F/15°C, only 40% of the seeds produce seedlings, compared to 97% at 68°F/20°C.

Celeriac should not be hardened off by reducing temperatures, as that can cause them to bolt. More than about 9 night temperatures below 55°F/12°C will cause bolting. Plants can have their watering reduced to help them get ready for the big outdoors. Use rowcovers if a cold spell arrives after you have planted them out, or if you know cold weather is likely to return. Falling apple blossom is a phenology sign that conditions are suitable.

See Root Crops in May for transplant info

See SESE’s Celery & Celeriac Growing Guide for growing information.

Kohlrabi

Harvested kohlrabi, Early White Vienna and Early Purple Vienna.
Photo McCune Porter

Kohlrabi is very easy to grow, treat it just like cabbage or kale.

It can be direct-seeded, but for an early crop, especially if you live in a climate like ours where spring turns into summer very quickly, use transplants. We don’t grow a lot, only 180 feet (55m) in total for 100 people. We also grow kohlrabi in the fall, transplanting bare root transplants from nursery seedbeds around August 3. We grow twice as much in fall as spring, because we can store them for winter.

We have grown both Early White Vienna and Early Purple Vienna. Growing both provides for pretty harvests. We sow February 8 at 4 seeds/inch (0.5 cm apart) in open seed flats, aiming to have the plants spotted out, hardened off and transplanted outdoors with rowcover on March 13. Fast work!

Root Crops to Harvest in Central Virginia in February

Hakurei turnips harvested late January.
Photo Pam Dawling

As for January, in central Virginia, there are normally no roots that we could be harvesting outdoors in February except parsnips, Jerusalem artichokes and horseradish.  We do have horseradish, but not the others. Of course, you can only dig up root crops if the ground is not frozen!

We have had outdoor night temperatures of 16°F/-9°C and 12°F/-11°C. This winter we have some carrots “growing” in the fresh air and some late-sown beets under rowcover. I don’t think we’ll get roots from the beets, but the leaves might make a nice change from brassicas as cooking greens.

In the hoophouse our radishes #3 (sown October 30) will come to an end by 2/1. Our #4 radishes will get harvested this month. Our #5 radishes, sown 12/23, will feed us from then until around April 7

We still have some of our first turnips (sown around October 13) until mid-February, and they have reached a really good size, thanks to early thinning. This month we can harvest the second sowing (October 25). We thinned turnips #2 in early January. They are looking good too.

Red Round turnips in our hoophouse in late January.
Photo Pam Dawling

We have not yet needed to unroll our inner rowcovers in the hoophouse. We wait until we expect it to get down to 8°F (-13°C) outdoors, as we like to avoid extra work!

Other Root Crop Tasks in Central Virginia in February

Potatoes stored in crates in our root cellar.
Photo Nina Gentle

Check stored vegetables

Stored crops need to be checked for decay at least once a month, preferably once a week now the days are getting longer and the temperatures will get warmer. From storage, we can eat beets, carrots, celeriac, kohlrabi, parsnips, potatoes, rutabagas, sweet potatoes, and turnips, if we grew them.

Special Root Crop Topic for February in Central Virginia

Wrap up the winter planning

Our garden planning wraps up by mid-February, with all the budgets, crew selection and shift decisions (afternoons in cold weather, mornings in hot weather –  we’re mostly half-day gardeners, with one or two stalwart all-day workers)

Order summer cover crop seeds

Buckwheat cover crop in flower.
Photo Pam Dawling

For early spring, if we find an area without a winter cover crop and we realize we won’t plant it with a vegetable crop for at least 8 weeks, we sow oats. They will smother weeds and add organic matter to the soil when you till them in.

If you have not already ordered summer cover crop seeds, this would be a good time to do so. Cover crops suppress weeds, add organic matter, feed the organisms in the soil and attract beneficial insects, birds and amphibians to feed and reproduce. Biodiversity encourages ecological balance that can help reduce plant diseases and pest attacks. Have a goal of No Bare Soil. Seek out odd spaces to fill with cover crops.

Once frosts are past, buckwheat is an easy cover crop. Its flowers attract beneficial insects, and it is a very manageable (not too tall) fast-growing crop. Buckwheat can be in and under in a month.

Just as fast is mustard, but we don’t grow that because it’s a brassica and we grow a lot of brassica food crops. Keeping a good crop rotation is important to us. Also we have harlequin bugs and we don’t want to feed them year round.

Sorghum-sudangrass hybrid is a fantastic, huge warm weather grass type cover crop, but don’t grow it if you have only a lawnmower, a scythe or a nylon line weed whip to cut it down! For smaller scale gardens, choose Japanese millet.

Soybeans, southern peas and sunn hemp are easy legume cover crops for warm weather, providing nitrogen for the next crop.

Cover cropping is a big topic. See my book Sustainable Market Farming for more. Here I’m just pointing you in the right direction enough to order seeds soon. You can read up more later.

Root Crops in January

No Root Crops to Plant in Central Virginia in January!

Closing rowcovers after a winter spinach harvest.
Photo Wren Vile

There is nothing, absolutely nothing, in the way of root crops that we sow outdoors here in January. Nor are there any root crops to sow in the greenhouse. Most root crops do not transplant well, as the replanting does too much damage to the taproot. Some exceptions are celeriac and kohlrabi (a stem vegetable more than a root, although I do tend to lump it in with root crops.) I have heard beets can be transplanted, especially if in soil blocks or plugs, and I’ve even heard of people up north transplanting plugs of rutabagas. I tend to be skeptical of books saying this or that can’t be transplanted, as I have transplanted many things. But not yet rutabagas or beets. I did roll my eyes when I heard someone propose transplanting mini-soil-blocks of carrots, using a pair of tongs made with popsicle sticks!

We are in winter-hardiness sub-zone Zone 7a, with an average minimum temperature of 0° to 5° F (-18°C to -15°C).

An Easter Egg radish in the hoophouse in January.
Photo Pam Dawling

Around January 26, we sow our last hoophouse radishes (sowing #6), Easter Egg, and White Icicle. This is our absolute last worthwhile sowing date. They will be ready for harvest from mid-March to mid-April, but if the weather is warm, or we fail to open the doors when we should, they will bolt before we get roots.

Our hoophouse radish sowing dates are 9/7, 9/30, 10/28, 11/22, 12/20, 1/27. Note that the sowing intervals are 23, 28, 25, 28, 38 days. The interval is much longer in December-January, as the rate of growth is so slow. There really is no point in sowing closer to the #5 sowing date, as the #6 will catch up in the warming days of late February and early March. The daylength is also increasing a lot by then, too.

If your hoophouse planting plans exceed the space you have, simply tweaking to a less frequent new harvest start could free up space to grow something else. Also consider a gap in radish supply, if other crops could make better use of the space. See Root Crops in September for more about our succession of hoophouse radish sowing dates.

In our double-layer hoophouse, turnips (and many cooking greens) can survive a hoophouse air temperature of 10.4°F (-12°C) without rowcover, -2.2°F (-19°C) with thick rowcover (1.25oz Typar/Xavan).

January photo of radishes sown in our hoophouse at the end of November.
Photo Pam Dawling

Root Crops to Harvest in Central Virginia in January

In central Virginia, there are normally no roots that we could be harvesting outdoors in January except parsnips, Jerusalem artichokes and horseradish. The months with R in them are the horseradish harvest months. September to April have R in them, and the summer months do not!

We have already had outdoor night temperatures of 16°F/-9°C and 18°F/-8°C. Until temperatures drop to 12°F/-11°C, we could dig Danvers carrots, Cylindra beets, and any rowcovered rutabagas (swedes). Albina Verduna, and Lutz Winterkeeper beets are hardy down to 15°F (-9.5°C), as are most kohlrabi, rutabagas and rowcovered turnips. Covered beets, covered winter radish are OK down to 10°F (-12°C). This is too chancy for us! We like to gather our root crops in and have them safely stored.

We store our root crops washed, in perforated plastic bags, in a walk-in cooler. Root cellars and cool basements are also possible storage sites, and in the past, I stored root crops in boxes of damp sand or woodash.

In the hoophouse we can normally harvest radishes #3 (sown October 30) all through January, from 12/15 to 2/1. This winter I notice we have already harvested most of them (1/6). We harvest our first turnips (sown around October 13) by pulling out the biggest from January 5 (or even late December), until mid-February, by which time we can have made a start on the second sowing (October 25). We thin the second sowing in early January or late December.

Young midwinter turnips in our hoophouse.
photo Pam Dawling

See my list of Winter-Kill Temperatures of Cold-Hardy Winter Vegetables 2020 for a more complete picture of “Harvesting in Time”

Other Root Crop Tasks in Central Virginia in January

Check stored vegetables

From storage, we can eat beets, carrots, celeriac, kohlrabi, parsnips, potatoes, rutabagas, sweet potatoes, and turnips, if we grew them. Stored crops need to be checked for decay at least once a month.

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

Inner tunnels in the hoophouse for cold nights

As noted above, inner rowcovers can make a big improvement to nighttime air temperatures in a hoophouse. We are fortunate to have a climate in central Virginia that means we don’t need inner covers most of the time. We watch the forecast and if we think it will drop to 8°F (-13°C) outdoors, we pull over the rowcovers. For winter crops we don’t use hoops. We have separate lengths of rowcover for each bed. Some people prefer a single large sheet. We find we can set the roll of rowcover at one end of the bed and simply walk with the free end down to the far end of the bed, leaving only a little bit of tweaking to get everything covered.

In the morning, if we feel pretty sure we’ll need the rowcovers again, we just pull the covers into the aisles, leaving every other path free to walk in. If we think we won’t need the rowcovers the next night we roll them up, giving us more space to work, and lengthening the lifespan of the rowcover by not exposing it to much sunlight.

Special Root Crop Topic for January in Central Virginia

Garden Plans Part Two

This garden planning task is not just about root crops. We had our Crop Review in November, and then inventoried our leftover seeds, planned what to grow for next year, and ordered our seeds. See Preparing to order seeds, if you haven’t sent in your orders yet.

We have made our garden maps, and specific plans for important crops with either lots of varieties (tomatoes), lots of sowings (sweet corn) or some combination (lettuce, broccoli and cabbage).

One task we need to complete by mid-January is to prepare our greenhouse seedlings schedule, because here we start sowings in mid-late January. We also tidy up the greenhouse (currently growing lettuce) and test, repair or replace vital equipment (like a seedling heating mat) and supplies like Bt and cover crops seeds.

Tomato seedlings (for our hoophouse) on a heat mat in our greenhouse in February.
Photo Pam Dawling

Another January task is to prepare a new Field Planting Schedule, or Outdoor Planting Schedule, as we call it here to distinguish it from our hoophouse schedule and our seedlings schedule. This is a list in date order of what to sow or transplant, how long the rows are, the space between rows, the space between plants (for transplants) and where to plant.

We also plan crops that will go in our raised beds from January to July. We plan the second part of the year in June, giving ourselves more flexibility.

See my Mother Earth News  Garden Planning online course for details

The map of our raised bed area, showing several years of crops using colored pens.
Photo Pam Dawling

We also revise and update our Garden Calendar (monthly task list). For those who want to think more widely about the coming year, here’s a link to The Complete Twin Oaks Garden Task List Month-by-Month

Our garden planning wraps up by mid-February, with all the budgets, crew selection and shift decisions (afternoons in cold weather, mornings in hot weather –  we’re mostly half-day gardeners, with one or two stalwart all-day workers)