Weeds of the Month for July: Pigweeds (Amaranth species)

 

Redroot pigweed
Photo by: D.G. Swan, WSU CAHNRS and WSU Extension

In May, I wrote about galinsoga, a warm weather annual that dribbles out seeds from an young age. In June, I wrote about docks, tap-rooted perennials that are best tackled early in life. This month is the turn of pigweeds, warm weather annuals that put out seeds in a “Big Bang” as Chuck Mohler describes in Manage Weeds on Your Farm. Pigweeds are fast-growing, tall, erect-to-bushy weeds that respond to high levels of nutrients as found in gardens and crop fields. Like corn, they use the C4 photosynthetic pathway, which means they thrive in high temperatures and high levels of light. They avoid getting shaded by growing fast, and they tolerate drought. Their vulnerability is that they do not produce seeds until they have been growing for some time and have reached a noticeable height.

Green Amaranth/Calaloo, grown for cooking greens.
Photo Baker Creek Seeds

Pigweeds are amaranths, a family that includes valuable food crops used for grains and greens, as well as dreaded weeds such as Palmer Amaranth, Waterhemp and Spiny Amaranth. Pigweeds are frost-tender, but if you have a long enough frost-free period, one plant can produce over 200,000 seeds.

Species of pigweeds

Mark Schonbeck has written a profile of pigweeds on the eOrganic site. He provides a list of eight unwelcomed pigweed species:

Silver Queen sweet corn with wilting pulled pigweed amaranth. Corn is a C4 crop, amarnath (pigweed) a C4 weed. Photo Kathryn Simmons.

Our experience with redroot pigweed in sweet corn

When I first encountered pigweed, I was told they were more-or-less impossible to deal with. Once I learned from Manage Weeds on Your Farm that, as tender annuals, they die with the frost, and as Big Bang weeds, they produce no seeds during most of their growth (unlike galinsoga!), I started a program of pulling them in our sweet corn patches. We used to grow a lot of sweet corn, and this tall crop, taking about ten weeks to mature the harvest, is a good habitat for pigweeds. We cultivate our sweet corn two weeks and four weeks after sowing, then don’t come back until the corn is ripe. This is an excellent window for pigweed to mature in! We started pulling the huge pigweeds each time we harvested corn. Inevitably, the weeds were right next to the corn plants, where our hoeing had failed to dislodge them. We found that if we put one foot against the base of the corn stalk and grasped the pigweed firmly and pulled up, we could usually tug them out. This won’t work if your soil is a tight clay, and if the pigweed breaks, the stem will branch and regrow. Most times, we harvest a patch of corn for two weeks and then disk or till it under. Usually we are turning the crop and weeds under before the regrown pigweed has had a chance to set seed.

Here is a video about Redroot Pigweed:

https://www.youtube.com/watch?v=Muqv3D-EujI

Economic weed thresholds of pigweed

Mark Schonbeck reports:

“Economic thresholds (weed levels that cause a 5% yield loss) for pigweeds emerging with corn and soybean crops have been estimated as low as 0.2–0.5 plants per 10 square feet, and 2–4 plants per 10 square feet for weeds emerging after crop seedlings have several leaves (Costea et al., 2004). In Ontario, redroot pigweed that emerged in corn at the 3–5-leaf stage at populations of 0.5–2.5 weeds per foot of row reduced yields 10–30%, whereas pigweed emerging at the 7-leaf stage had little effect (Knezvic et al., 1994)”

Our experience was that our corn yields were good, and we had found a successful method to manage the levels of pigweed over several years. We were cultivating between the rows and undersowing with soy at 4 weeks after sowing the corn, so the pigweeds growing were only those very close to the corn stalks. I do picture that an understory of pigweed would have a serious effect.

Spiny Amaranth

Spiny amaranth – a weed to exterminate by careful pulling.
Photo Pam Dawling

Spiny amaranth has been designated the world’s 15th worst agricultural weed. We have twice eliminated spiny amaranth from our gardens for a number of years, and then had it return. The seeds can remain viable in the soil and regrow when they are exposed to light. Although not as tall-growing as redroot pigweed, spiny amaranth has other ways of succeeding against those who would remove it from their crops: The nasty 0.5” (13 mm) spines (borne in opposing pairs at each leaf node) are not very visible among the branches, and are close enough together to make grasping the stem difficult.

The leaves of spiny amaranth are a darker green than redroot pigweed and have a V-shaped mark in a different color. Spiny amaranths can produce even more seeds than redroot pigweed: 235,000 each. Beware importing animal manure from other farms, and even gravel. I have seen a spiny amaranth germinate in a fairly large gravel pile brought in for road repairs.

Six methods of tackling pigweeds

Mark Schonbeck lists six methods of tackling pigweeds in organic production systems, and recommends using a combination of:

  • Cultivation, flame weeding, and manual removal 2-3 weeks after emergence
  • Stale seedbed
  • Mulching
  • Crop rotations that vary timing of tillage and other operations [our sweet corn was one year in 3 or4]
  • Cover crops and competitive cash crops
  • Measures to prevent or minimize production of viable seeds

Pigweed Flea Beetle

Disonycha glabrata – Pigweed Flea Beetle.
Photo from Bug Guide.net

Pigweeds even have their own striped flea beetle, Disonycha glabrata from the Chrysomelidae family. It is a large flea beetle. More the size of a striped cucumber beetle, but with a reddish thorax. It feeds on Redroot Pigweed (Amaranthus retroflexus) and other amaranths, so we never even try to grow salad amaranths as the leaves get riddles with holes. The first larval stage lasts 3.6 days, the second 2.6 days, and the third 2.9 days.  It spends 13.5 days in the soil.

Another Weed Management Resource

The book Steel in the Field, available as a downloadable pdf from SARE

Steel in the Field: A Farmer’s Guide to Weed-Management Tools. 1997. Edited by Greg Bowman. Sustainable Agriculture Research and Education (SARE). This book is a farmer’s guide to weed management tools using cultivation equipment.

Success with Growing Cabbage in Spring

Young Early Jersey Wakefield cabbage, a fast maturing pointed variety.
Photo Pam Dawling

Some of this material is from my book Sustainable Market Farming.

Cabbages can be reliable workhorses, providing large harvests over long periods. In colder regions, cabbages are planted only in the spring and grow all summer, into the fall and winter, until cold weather kills them. In the South, they are a spring/early summer and a fall/overwintered crop, as it’s too hot to grow them in the summer. In parts of California and the Pacific Northwest, they’ll grow year-round.

Cabbage crop requirements

Cabbages do best on fertile, well-drained soil with adequate moisture. They require a lot of potassium, so a sprinkling of wood ash, kelp meal or granite dust could be helpful. Calcium, boron, iron, manganese and molybdenum are also important for good brassica crops — healthy, biologically active soils can usually supply enough of all these. If not, amend as needed.

Young Farao cabbage, a good fast-growing round variety.
Photo Pam Dawling

Cabbage varieties

Be clear about what kind of cabbage you are looking for, especially whether it’s for fresh eating, slaw, sauerkraut or storage, and what size you want and how many days from seeding to harvest.

  • For quick-maturing cabbage, we choose Early Jersey Wakefield (63d OP), Golden Acre (62d OP) and Farao (64d F1) (All days to maturity in this list are from transplanting in spring. Add 14 days for direct sowing. Subtract 10-14 days for warm weather sowings.)
  • For large solid cabbage for making sauerkraut, we choose Gunma (110d F1), Tribute (103d F1) or Early Flat Dutch (85d OP)
  • For a green cabbage that holds well in hot weather, to extend the season as long as possible, the flat Tendersweet (71d F1) is tasty and works well for us. It is good for coleslaw and wraps, but not for storage
  • We like a red that’s fairly large and yet quick-maturing (many reds are too slow for us, taking us deep into hot weather). We used to favor Super Red 80 (73d), but gave it up after two poor years. Ruby Perfection (85d F1) stores fairly well, as does Integro (85d F1)
  • We like savoy cabbage, and find Melissa (85d F1) and Famosa (80d F1) quick and reliable
  • For storage we have liked Storage #4 (95d F1), Kaitlyn (94d F1), and Late Flat Dutch (100d OP)
  • Deadon (105d F1) is a particularly cold-hardy one to grow into the winter. It survives down to at least 10°F (-12°C)
  • High Mowing and Johnny’s Seeds have good selections of over twenty cabbage varieties, including the 77d 10-17 lb (4.5-7.7 k) Megaton, good for fresh eating and kraut.

Sowing cabbage seed

A seed flat of cabbage and several flats of spotted out seedlings in our greenhouse in February.
Photo Pam Dawling

In early spring, transplants have the advantage over direct-seeded crops — they grow faster under protected conditions and bring earlier harvests. At other times of year, you may prefer to direct seed.

Work back from your desired harvest date to calculate the sowing date. Naturally you’ll need to allow for your climate and choose a realistic transplanting date. We start our very first cabbages in our greenhouse in mid–late January, as soon as I’m mentally prepared to start a whole new year. Maincrop cabbage follows in mid-February.

Despite being a cool-weather crop, brassicas actually germinate very well at high temperatures: the ideal is 77°F–85°F (25°C–30°C), and 95°F (35°C) is still OK. Given enough water, the seedlings will emerge in four and a half days at the low end of this range, and at the top in only three days. The minimum temperature for good germination is 40°F (4.5°C), but you’ll need to wait more than two weeks for emergence if it’s that chilly.

We start our spring cabbages in home-made open wood flats, sowing 3–4 seeds per inch (5–10 mm apart). We press a plastic ruler 0.25″ (6 mm) deep into the seed compost to make a small furrow, spacing the rows 2″–3″ (5 cm) apart.

Once they have emerged, the seedlings need good light, nutrients, airflow and protection from bugs. 60°F–70°F (15°C–21°C) is a good temperature range for growing them. As soon as the seed leaves are fully open, we spot (prick) them out to 4″ (10 cm) deep flats, with 40 plants per 12″ x 24″ (30 x 60 cm) flat. The plants grow to transplanting size in these flats.

Spotting cabbage seedlings from a seed flat into a transplant flat.
Photo Wren Vile

For the last two weeks before transplanting, harden off the plants by moving them into cooler, breezier, brighter conditions.

Transplanting cabbage

We grow spring cabbage in 4′ (1.2 m) beds, at two rows per bed, with plants 18″ (50 cm) apart. Mini-cabbages can be spaced at 8″–12″ (20–30 cm) in the row, with rows 12″–18″ (30–45 cm) apart, and may give higher total yields as well as heads of a more useful size.

We aim to transplant at four true leaves (5–8 weeks after sowing in spring). This is early to mid-March for the earliest cabbage (seven weeks old), very early April for maincrop cabbage. Soil temperatures of 65°F–75°F (18°C–24°C) are ideal. Optimal air temperatures for most brassicas are 60°F–65°F (15°C–18°C).

Water the seedlings well before transplanting, and plant all the way up to the base of the first true leaves to give the stem good support. Press the soil very firmly around the plants so the roots have good soil contact and won’t die in an air pocket. I was taught to tug on a leaf after transplanting: if well planted the leaf will tear and the plant will remain in the ground. Water within half an hour of planting and again on the third and seventh days, and then once a week.

Young spring cabbage with a hay mulch. Wren VIle

For cabbage, the sixth and seventh leaf stage is the most vulnerable. If the weather deteriorates at this critical time, give your plants extra protection. High daytime temperatures can to some extent compensate for low nighttime temperatures — it’s cold days and cold nights together that do the damage. We use thick rowcover over our spring cabbages for a few weeks after transplanting, then may switch to insect netting.

Two weeks after transplanting, we check the plants and fill the gaps with transplants we have kept for this. If it is necessary to use big plants to fill gaps, we pinch off a few of the lower leaves to reduce their water needs.

Caring for  cabbage in spring and summer

About a month after transplanting maincrop cabbage (mid-May), we remove the rowcovers and the sticks we use to hold them down.

We use only overhead sprinkler irrigation (not drip tape) for spring cabbage, which helps cool the leaves and can wash off aphids. Organic mulches help keep the soil cool, as well as adding lots of organic matter to the soil. Brassica roots are relatively shallow, so long droughty spells without irrigation can cause problems. One inch (2.5 cm) of water per week is about right.

One of our impact sprinkler tripods, in a broccoli and cabbage patch.
Photo Pam Dawling

Cabbage pest control

Using rowcovers or insect netting keeps many pests off the plants while they are small. We have not had much trouble with aphids, perhaps partly because of our overhead sprinklers; insecticidal soap sprayed three times, once every five days, can usually deal with them. Our worst pest is the harlequin bug. When necessary, we handpick them. Ladybugs are reputed to eat harlequin bug eggs.

Sometimes we have had enough cabbage worms to make Bt (Bacillus thuringiensis) necessary, but usually paper wasps eat the caterpillars. The action threshold is an average of 1 cabbage looper, 1.5 imported cabbageworms, 3.3 armyworms or 5 diamondback moth larvae per 10 plants. Below this level you can do watchful waiting rather than spraying with Bt or spinosad. Apparently paper or plastic fake cabbage moths on sticks will deter more from moving in. There are templates for homemade cabbage moth decoys online. The eyespots are important!

Yarrow flowering in our hoophouse in late November, 13 months after sowing.
Photo Pam Dawling

We are also lucky enough to have the naturally occurring wasp parasite of cabbage worms, the Braconid wasp Cotesia species, which are found as small cottony white or yellowish oval cocoons in groups on brassica leaves. The Cotesia wasps like umbelliferous flowers, and overwinter on yarrow as well as brassicas. If you find Cotesia cocoons and your brassicas aren’t diseased, you can leave plants in the field over winter. Or you could collect up leaves with cocoons in late fall and store them at 32°F–34°F (0°C–1°C) until spring. Hopefully no one will clean out your fridge without asking.

To float out worms and aphids after harvest, soak the produce in warm water with a little vinegar for up to fifteen minutes, then rinse.

Harvesting cabbage

Our cabbage heads up from May 25 and some hold till July 15. For storage cabbage (a valuable crop in summers in warm climates with scarce fresh leafy greens), we set the cut heads upside down on the stump, in the “basket” of outer leaves, and come back an hour later to gather them into net bags. This allows the cut stem to dry out and seal over, improving storability.

Mature Farao early cabbage. Note the curling-back leaf on the head, a sign of maturity.
Photo Pam Dawling

Vegetable Seed Varieties for 2024

 

Preparing to sow Rainbow Chard in 2018.
Photo Pam Dawling

Vegetable Seed Varieties for 2024

Have you ordered your seeds for next year yet? The earlier you order, the best chance you have of getting the varieties you want. Later, some will sell out. It’s true that when you order very early, some seeds won’t be available yet. The seed growers are still drying and cleaning them, weighing them and running them through germination testing. Your patience will be rewarded with high quality seeds.

I love looking through catalogs to find new exciting-sounding varieties! After so many years of gardening, I’ve tried lots of different kinds, and have definitely grown attached to some reliable favorites. I recommend planting a small amount of a variety new to you that sounds good, alongside your usual well-loved variety. And what do I mean by “sounds good”?

In 2014 I wrote Reading Between the Lines in the Seed Catalogs to share what I’d learned about decoding catalog-speak, and not getting distracted by wondrous claims, failing to notice the catalog never even claimed it had good flavor. Or high yields. Or good disease-resistance. That post lists 15 features to look for.

We look for flavor, productivity, disease-resistance, an appropriate fit with our climate or latitude, general adaptability, varieties that don’t require erecting elaborate trellises, ones that don’t sprawl too widely, ones that don’t take a really long time to reach maturity.

If we’ve had a few years of poor performance from a crop, we’ll try several new varieties. We have done trials of heat-tolerant eggplants, winter spinach for the hoophouse and outdoors, storage cabbage, and now we need to start over with broccoli.

Green Magic broccoli Credit Johnnys Seeds

For many years we grew three varieties of hybrid broccoli with different number of days to maturity. That enabled us to sow them all on the same day, transplant them all on the same day (or in the same week), and get an extended harvest period. Some of our favorites dropped out of the market, we floundered with various kinds, including some Open Pollinated varieties that sounded good. This year I am advocating for Green Magic (57d F1, 6-8″ main head and sideshoots too); Belstar (65d F1, also 6-8″ main head, plus sideshoots); and Marathon (68d F1) or Fiesta (70d F1, 6-7″ head, few sideshoots, short harvest window). Marathon has done well for us in the past. In my experience, broccoli is a crop where hybrids are much more productive than OP types.

Green Machine zucchini. Photo Johnny’s Selected Seeds

Our much-loved Tendergrey zucchini, one of the flecked pale green types, isn’t easily available this year. But Green Machine (45d F1) sounds very good! Open plant habit is a phrase I like. Moderate spines is one I don’t like, but we have some pull-on plastic sleeves to deal with irritating plants. Widely adapted, excellent disease package, and high yields all appeal to me.

We rely on Provider (50d OP) and Bush Blue Lake snap beans every year, with a short row of Strike in the hoophouse a month earlier than outdoors. We found we need an upright variety to get nice beans undercover, as the bean plants grow sprawlier than they do outside, and we don’t want to be treading on them.

Washing Cylindra beets for storage.
Photo Wren Vile

We rely on Cylindra or Formanova (54d OP) beets, long-shaped tender ones that grow up out of the ground, are tender and easy to peel after cooking. Seems like the yield must be high when half the root is above ground, and half below!

Premium Late Dutch cabbage (100d OP) has done well for us. Johnny’s has a lovely-sounding storage cabbage, Promise (96d F1). 6 ½ lbs at 18″ spacing, 9-10 lbs at 24″ spacing. And two attractive purplish Chinese cabbages Red Trumpet (60d F1), a tall Michihili type, and Merlot (60d F1), said to be an improved Red Dragon Napa type. I hadn’t got round to trying Red Dragon yet, so I can’t speak to its shortcomings. Merlot admits to being more prone to tipburn than green varieties and to be somewhat susceptible to bolting. Some trials on a small-scale are called for!

Merlot purple Chinese cabbage.
Photo Johnny’s Selected Seeds

Carrots – oh why so many yellow, purple, red and black ones? None in my experience match the succulence and growth rate of orange Danvers 126.

Collards – for years I have loved Morris Heading, but the recent explosion of options brought us by the Heirloom Collard Project is leading us to try others. Some have remarkable colors, combined with high yields.

The delicious early Bodacious sweet corn is harder to find. Thanks Southern Exposure for carrying it. Our reliable favorite Kandy Korn has become hard to find.

Our favorite slicing cucumber has been renamed by Fedco as Generally, a name we’ve been using for years. This year we also tried South Wind from Common Wealth Seed Growers and were quite taken with its sweetness.

South Wind slicing cucumber.
Photo Common Wealth Seed Growers

As always, there are new frilly mustards for baby greens and salad mixes. We like Mizuna, Golden Frills, Scarlet Frills and especially Ruby Streaks. I feel drawn towards purple stemmed Ember and dark red Miz America.

For leeks, we grow King Richard and Lincoln for fall and Tadorna for overwintering in our Zone 7a climate. No complaints there. all are very good for their purpose.

I’m always on the lookout for new lettuces. This summer we tried Albachiara from High Mowing, and it did very well. We’ll get more for this coming year. It’s a Batavian heat-tolerant type. Now our climate is changing, we need to grow Batavians for more weeks of heat. Finding a new one is great! Dark red Cherokee has been my favorite.

I shouldn’t even look at the spring lettuce selection, or I’ll order more than we can use in the short spring season we have. Most spring varieties can be grown in the fall here too, but we like to switch to cold-tolerant ones.

Ezrilla, a favourite cold-hardy lettuce.
Photo Wren Vile

This winter we are growing the beautiful Rhone in our hoophouse bed of cut-and-come again leaf varieties, along with Ezrilla, Hampton, Brentwood, Tango, Revolution, Oscarde and Panisse.

For scallions we like Evergreen Hardy White (65d OP) every time, and feel no need to try another.

We have been growing Sugar Ann early dwarf snap peas in our hoophouse (sown Feb 1), but next year we are trying Oregon Giant snow peas instead. We think snap peas are best raw, and used to cut them into our salad mixes. But over the past few years, by the time the snap peas are ready to harvest, our winter salad mix days are coming to a close, and our outdoor lettuce head harvest is starting. We don’t grow enough snap peas to serve them on their own in big bowlfuls. We think we’ll be able to pick enough snow peas for stirfry mixes instead! In March we sow Sugar Ann outdoors and get plenty.

For sweet peppers our keywords are prolific, thick-walled, tasty, and 90 days or less from transplant to ripe harvest (76d to green). We like fairly large peppers too, and avoid small pointy ones that could get confused with hot peppers in the fridge.

Tomatoes are a whole topic on their own. We love Sun Gold and Black Cherry, Mountain Magic and Garden Peach. Others come and go. Next year we are trying Damsel  (73d F1). Damsel is in the new tomato category called “Hylooms” – hybrids resembling heirlooms in color and flavor, with added disease resistance.

Damsel (71d F1) Hyloom tomato.
Photo High Mowing Seeds

Success with Spinach for Fall, Winter and Spring

January spinach from our second hoophouse sowing.
Photo Pam Dawling

Success with Spinach for Fall, Winter and Spring

Spinach is a much-loved crop for us. We sow outdoors and in the hoophouse in early September for harvesting from fall through to spring (April). We sow outdoors in late September for a crop to overwinter as small plants and be harvested in the spring. We also sow in our coldframes in mid-September. These are more sheltered than the beds outdoors, and the spinach makes faster growth. We sow more spinach in the hoophouse in October and November. We sow in the hoophouse in January to transplant outdoors and in the hoophouse in February for spring harvests. We are able to keep harvesting spinach (leaves, not whole plants) from October 15 to May 25, all the way through the winter. Central Virginia is too hot to have spinach during the summer (we switch to chard).

Spinach over-wintered in our cold frame
Photo wren Vile

Unsurprisingly, I have written about spinach several times.

Spinach Variety Trials Conclusion in May 2019. Our top general favorite is Acadia, although Reflect does better outdoors overwinter. This post includes links to earlier posts about spinach varieties, including Spinach Trials Update, April 2018.

What causes spinach leaves to turn yellow, in May 2019

yellowed spinach in May. We had transplanted too soon after tilling under some big weeds.
Photo Pam Dawling
A bed of healthy green Reflect spinach on May 3
Photo Pam Dawling

What makes vegetable crops bolt and how can I stop it? March 2021

Spinach Varieties

Choose varieties that do well in climates similar to yours, in the conditions you have when you plant and harvest. We used to grow Tyee for all plantings, and were very happy with it. But it has been pulled from the market because it had disease problems in the Pacific North West, where spinach seed is grown. We have tried and not continued Chevelle, Corvair, Renegade (grows fast, but has thin leaves and bolts early in spring), Avon (Downy Mildew in winter).

Also see the 2015 Greenbank Farm Spinach Variety Trial. The farm is in Washington State. They evaluated 10 varieties of savoyed and semi-­‐savoyed spinach with two side-­‐by-­‐side replication in spring. Abundant Bloomsdale, Bloomsdale Long Standing, Butterflay, Giant Winter, Dolce Vita, Longstanding Bloomsdale, Lyra, Solstizio, Tyee, Winter Bloomsdale. The overall star of their trial was Solstizio from Nash’s Organic Produce.

Spinach plants on February 5. left to right: Avon, Renegade, Escalade, Acadia.
Photo Pam Dawling

Paul and Sandy Arnold in Argyle, New York, made a great slide show reviewing Spinach Varieties in High Tunnels.  I think it’s no longer available online, but I did learn that in 2019, their top Winter Spinach Varieties were Escalade, Carmel, Whale, Space, Reflect; top Summer Spinach Varieties: Banjo, Seaside, Woodpecker.

In 2011-2012, High Mowing Seeds in northern Vermont did a spinach variety trial with 24 varieties. Three farmers in Iowa conducted a 2021 trial of spinach varieties and seedling methods. They compared yield, bolting and yellowing among three spinach seeding methods: seeder (1x rate), seeder (2x rate), hand-seed (2x rate); and between two varieties (Kolibri, Kookaburra). Two of them found no statistically significant difference of seeding method on yield; one found no difference in yields between the two varieties, but using a seeder at a double rate produced significantly higher yields than the other two methods.

When to sow fall spinach

Spinach does not germinate in hot soil! Use a soil thermometer and wait for the soil to cool to 68F (20C), or see the next section about sprouting spinach seed in a cold place. If you have no soil thermometer, see my post chickweed, hen-bit and dead-nettle, and use the info that was originally written with lettuce in mind, for spinach! There are photos there of these three plants at seedling stage. These are winter annual weeds here, that don’t grow in summer. Once we see their seedlings emerging in late August (a cool summer year like 2023) or September (most years) we know the soil has cooled enough to sow lettuce and spinach directly in the ground.

A trick for getting good timely germination of spinach seed is to put it (in sturdy resealable plastic bags or jars) in the freezer for about two weeks. Take the seeds out of the freezer the day before you want to sow (or start sprouting them), but – important – do not open the bag or jar. Leave it to warm to ambient temperature before opening. Otherwise the warm humid air will rush in and coat the cold seeds with condensation, reducing the shelf life of whatever seed you have left over for another time.

See our Spinach Variety Trials and Planting Plan, in February 2018:

  • September 6 is our first sowing (sprouted seeds) in the hoophouse for winter harvest 10/30-2/15, or later if it doesn’t bolt.
  • We sow outdoors on September 7 (sprouted seeds) for growing under rowcover and harvesting in fall and winter.
  • September 18-20 we sow in our coldframes and outdoors for harvest in early spring, until late May.
  • October 24 we make our second hoophouse sowing, to feed us November 25 to May 7.
  • On November 9,we make a third hoophouse sowing, intending to use these plants to fill gaps in our hoophouse as other winter crops come to an end.
  • January 16 we make more sowings in the hoophouse, some to continue to fill gaps there along the edges of the beds where they won’t fight with the tomatoes and so on, which we transplant starting March 15. Most of the spinach sown on this date is for transplanting outdoors on February 21.
  • January 29 we sow in flats in the greenhouse if we see we haven’t got enough bare-root transplants in the hoophouse.
  • February 10 If we don’t have enough transplants, then on this date we sow outdoors with rowcover, for spring harvests until May 25 if we’re lucky. We have backup plans on backup plans for this!
  • In the hoophouse we continue transplanting spinach to fill gaps until March 31.

 

Sprouting seeds before sowing is a way to success in hot or very cold weather.
Photo Pam Dawling

Sprouting Spinach Seed

This very easy work-around involves soaking the spinach seed in water overnight, draining it, and putting the jar on its side in the fridge for a week. If you remember, give the jar a quarter-turn each day to even out the moisture. You are not growing bean sprouts! A little neglect will not cause harm. The ideal is to have short sprouts, not long ones, as those break off more easily.  Sow the seed in the furrows gently, by hand. If the sprouts have got tangled, add some water to float them apart, drain them, spread them on a tray, or a layer of rowcover, to dry a bit, then mix with some inert dry soil-friendly material like uncooked corn grits or bran, which will help them not stick together.

Sowing Spinach in Speedling Flats and Floating them in Water

Another option is to start the spinach in flats and transplant it all. That’s a lot of work, but we found we could save on the daily attention time and the transplant time by using 120-cell Styrofoam Speedling flats. Sow one or two seeds per cell, then float the flats all day in water. Depending on your scale, this could be a baby bath or a stock tank. Remove the flats each evening and let them drain all night (while it is hopefully cooler). With just twice a day visits and no hand-watering, this is a big time saver, and we have got good germination rates.

Transplanting spinach from a Speedling flat. Butter knives are the tool of choice for easing the little wedges out of the tapered cells.
Photo Denny Ray McElya

When it comes time to transplant, the tool of choice is a butter knife. Use the knife to wiggle a wedge-shaped hole in the bed. Slide the knife down the sloping side of the cell, and, holding the base of the plant with one hand, use the knife hand to lift and flick the plug out. If all goes well, the plug will be then be resting on the now-horizontal knife, and you can slide it into the pre-made hole and firm it in.

Growing Spinach

Spinach makes growth whenever the air temperature is 40F (4.4C) or more. So any winter protection you can provide, in the way of cozy microclimates, rowcover, coldframes, or a hoophouse, will increase your yield. Spinach is more cold-hardy than many people realize. It dies at 0°F (-18°C) unprotected outdoors. Savoyed varieties tend to be a little hardier than smooth-leaved types. Large-leaved savoyed spinach outdoors with no protection can get seriously damaged at 10F (-12C). Small-leaved plants are OK down to 5F (-15C).

Weeding rowcovered spinach in winter.
Photo Wren Vile

Our outdoor spinach gets hoops and thick rowcover (Typar, 1.25 oz/sq yd spunbonded polypropylene, with 75% light transmission, and about 6 F (3.3 C) degrees of frost protection). It can last for 6 years or more. When we got 0F (-18C) the spinach leaves that touched the rowcover got big patches of beige/tan dead cells, but the plants recovered to produce more leaves.

Ben Hartman (author of The Lean Farm) wrote Testing the Limits of Cold Tolerance in Growing for Market magazine in February 2014. He reported that his young hoophouse spinach in Goshen, Indiana, with mid-weight rowcover survived -16F (XXX). Ben points out that spinach less than 1″ (2.5 cm) tall is very cold-tolerant. Bigger plants need more protection if it’s going to get that cold.

 You can read more about growing spinach in my Cooking Greens monthly series.

Growing bare root spinach transplants

Small spinach seedlings for bare root transplants. Photo Pam Dawling

We grow our spring spinach transplants (as well as kale and collards) in the soil in our hoophouse, sowing them in late January. See bare root transplants . You can find more links and info in that post. Growing bare root transplants saves a lot of work and a lot of greenhouse space.

Harvesting Spinach

Our goal is sustainable long-season harvesting. This is important for winter crops, as making a new sowing during cold dark days will not produce much food until spring comes around. It’s like the goose that lays the golden eggs – keep the leafy “golden eggs” coming

We harvest spinach by cutting individual leaves and leaving the plant to continue to produce more.

Our rule is “Leave 8 for later” – cut off large outer leaves close to the base of the plant, being sure to keep at least 8 of the inner leaves growing on each plant. Over-harvesting leads to decline.

When we finally pull up the bolting plants in spring, I’m always amazed to see how many leaf-scars there are on each plant, showing just how much we’ve harvested.

Hoophouse spinach. Far row: bolting Renegade; Near row: Escalade.
Photo Pam Dawling

For those relatively new to this blog but living in a similar climate zone, I want to point you to The Complete Twin Oaks Garden Task List Month-by-Month. It includes a link for each month’s task list. I notice from the site stats that some of you are finding your way there, but now there are so many years’ worth of posts it’s perhaps harder to find. Happy browsing!

Year-Round Hoophouse Vegetables slideshow, VABF Handouts

Tatsoi in the mist, November.
Photo Wren Vile

Busy Conference Season is here!

I just got back from the Virginia Association for Biological Farming conference in Roanoke. There I gave a half-day presentation on Year-Round Hoophouse Vegetables, which you can watch here:

Year-Round Hoophouse Vegetables 240m

The conference was very well-attended, and not everyone at my workshop on Friday, or the Alliums Year-Round 90 minute workshop on Sunday morning got a handout. I promised to post them here, and now I’m making good. I’m also posting the handout for the third workshop I gave, Asian Greens in the Winter Hoophouse. This rounds out the set, and gives a chance to those who went to a different workshop at that time to get a look in.

Year-Round Hoophouse Vegetables 8 pg handout 2023 Alliums Year-Round Asian Greens in the Winter Hoophouse 2023

This coming weekend I will be venturing north to NOFA-Mass and giving a presentation on Crop Planning for Sustainable Vegetable Production.

To those who are wondering what happened to my monthly post Fruit for the Month, I postponed it. There isn’t so much fruit in January, is there?

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.

Planning and Growing Winter Hoophouse Vegetables

 

Hoophouse winter greens.
Photo Kathleen Slattery

If you have a hoophouse, you may now be planning or planting crops for fall, winter and spring. If you don’t have a hoophouse, this is a good time of year to consider getting one. See Twenty Benefits of Having a Hoophouse at the end of that post. There are grants available from NRCS, including reparation levels of funding from traditionally underserved groups of people. There are now companies that will construct your hoophouse for you, if you don’t want to do it yourself, or can’t. If you do want to build your own, there are detailed instructions in my book The Year-Round Hoophouse. You can buy the book here on my Books page direct from me, or from my publisher New Society, or you can buy it wherever books are sold.

The Year-Round Hoophouse cover

I have many posts about winter hoophouse vegetables, so rather than try to write something completely new on the topic, I am going to give you a guide to find your way around the information already here.

General Hoophouse Info

Winter hoophouse growing

Hoophouse video interview

Year-Round Hoophouse Vegetables slide show

Hoophouse Cool Season Crops slideshow

Hoophouse Many Crops slideshow

Hoophouse Bright Lights chard in winter.
Photo Wren Vile

Hoophouse Crop Planning

Planning winter hoophouse crops

Hoophouse Crop Rotations

Preparing for spring, sowing seeds, planning

Hoophouse Greens Clearance, Warm Weather Crops Established

Hoophouse Crops Winter 2022-2023

Hoophouse Bed Prep

Hoophouse fall bed prep

Fall hoophouse bed prep

Hoophouse bed broadforked to loosen up slumped soil. I’m happy to say our soil structure has improved in the 18 years since this photo was taken!
Photo Pam Dawling

Choosing Hoophouse Winter Crops

(see also my post categories on the right side of the computer screen, for special posts on Asian Greens, Cooking greens, lettuce and root crops)

How to decide which vegetable crops to grow

Winter-Kill Temperatures of Cold-Hardy Vegetables 2021

Spinach variety trial conclusions

September in the hoophouse: sowing spinach

Young spinach seedlings.
Photo Pam Dawling

Sow onions in a hoophouse

Frilly Mustards in our Winter Hoophouse

Three cheers for Ruby Streaks!

Yukina Savoy in the Hoophouse

Cooking Greens in December

Cooking Greens in February

Cooking Greens in March

Yukina Savoy in the early morning mist.
Photo Wren Vile

Asian Greens in October: Yukina Savoy, Tatsoi

Asian Greens for December: Pak Choy

Asian Greens for January: Chinese Cabbage

 

Green Panisse and red Revolution lettuce in our hoophouse in November.
Photo Pam Dawling

Lettuce All Year in a Changing Climate

Year Round Lettuce

Lettuce growing in October

Lettuce in December

Lettuce varieties for January

Early Lettuce Production

Cold-tolerant lettuce and the rest

Tango lettuce from our September 24 sowing on January 10.
Photo Pam Dawling

Planting in the Hoophouse (Both Transplanting and Direct Sowing)

The decision between transplanting and direct sowing

Sowing hoophouse winter crops

Seedling winter crops

Starting Seedlings

Bare Root Transplants

September sown White Russian kale (transplanted in October).
Photo Wren Vile

Keeping Every Hoophouse Bed Fully Planted and Productive

Using all the space in the winter hoophouse

Fast Growing Vegetables

Sequential Planting slideshow

Young Tokyo bekana transplant in our hoophouse .
Photo Pam Dawling

Caring for Hoophouse Crops

What makes vegetable crops bolt and how can I stop it?

You don’t want this! Bolting lettuce outdoors in July
Photo Alexis Yamashita

What to Do If Something Goes Wrong with Your Hoophouse Crops

Back-up plans for winter hoophouse crops

Plans A-D

Emergency back-up seedlings for the hoophouse.
Photo Pam Dawling

Harvesting in the Winter Hoophouse

Winter hoophouse harvests

Mid-winter hoophouse harvests

This winter week in the hoophouse

Young greens in the hoophouse

Winter Harvests

Making baby salad mix

Beautiful baby lettuce mix in our hoophouse.
Photo Wren Vile

Time to Sow More Fall Brassica Crops

 

Young tatsoi plants.
Photo Bridget Aleshire

See my recent post for info about fall broccoli and cabbage. Here I provide some more information and discuss other brassicas you could grow in the fall.

Temperature and Timing for Fall Brassicas

  1. Germination: Brassica seeds will germinate at soil temperatures from 41°F (5°C) to 95°F (35°C). 41°F (5°C) can take 45 days for some brassicas, but in summer and fall, this isn’t the end of the thermometer we worry about! In summer and fall, soil temperatures are enough to germinate brassicas in 3-10 days. Optimum soil temperatures for germination are
  • 77°F (25°C) for most Asian greens, broccoli, Brussels sprouts, cauliflower, collards, kohlrabi, pak choy;
  • 86°F (30°C) for cabbage, including Napa cabbage, kale, turnips and rutabagas;
  • 68°F (20°C) for mustard greens, and perhaps arugula (which might do better even cooler)
Vates kale seedlings for bare-root transplanting outdoors.
Photo Pam Dawling
  1. Cold-Hardiness: Consult this list of winter kill (air) temperatures for brassicas, for the crops you are growing.
  • 32°F (0°C):  some cauliflower curds, some pak choy
  • 27°F (-3°C): many cabbage varieties
  • 22°F (-6°C): some varieties of arugula
  • 20°F (-7°C): 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, some collards (Georgia Cabbage Collards, variegated collards), some mustards/Asian greens (Tendergreen), radishes (Cherry Belle), most turnips (Noir d’Hiver is the most cold-tolerant variety).
  • 15°F (-9.5°C): some broccoli and cauliflower leaves, some cabbage (Kaitlin, Tribute), Red Russian and White Russian kales, kohlrabi, rutabagas (American Purple Top Yellow, Laurentian), most covered turnips, winter cress.
  • 12°F (-11°C): some broccoli perhaps, some Brussels sprouts, some cabbage (January King, Savoy types), most collards, Koji greens, covered rutabagas
  • 10°F (-12°C): Purple Sprouting broccoli for spring harvest, a few cabbages (Deadon), some collards (Morris Heading can survive at least one night), Belle Isle upland cress, probably Komatsuna, Chinese Thick-Stem Mustard may survive down to 6°F (-14°C), covered winter radish (Daikon, China Rose, Shunkyo Semi-Long survive), Senposai leaves (the core of the plant may survive 8°F/-13°C), Tatsoi, Yukina Savoy.
  • 5°F (-15°C): some kale (Winterbor, Westland Winter), many of the Even’ Star Ice Bred greens varieties and the Ice-Bred White Egg turnip are hardy down to 6°F (-14°C)
  • 0°F (-18°C): some collards (Blue Max, Winner, McCormack’s Green Glaze), Even’ Star Ice-Bred Smooth Leaf kale
  • -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.
Frosty daikon leaves.
Photo Bridget Aleshire
  1. Your Climate: Consult WeatherSpark. com to see when it begins to get too cold in your area. At our farm, the average daily low temperature on November 30 is 36°F (2°C). Decide your ideal harvest date for each crop. Although kohlrabi can take 15°F (-9.5°C), I’d want to get it all harvested by November 30.
  2. Days to Maturity: Next factor in the number of days a crop takes to reach maturity. Work back from your desired harvest date, subtracting the number of days from sowing to maturity (or from sowing to transplant, plus from transplant to maturity). Work back another two weeks for the slowing rate of growth in fall. And perhaps work back another two weeks in case in gets colder earlier than usual. This provides your sowing date.
  3. Mid-Winter Harvests: For crops that survive your winter, are you sowing to harvest in the fall, during the winter, or only in early spring? Brassicas for early spring harvest only can be sown in September or October in our climate. For those to be harvested during the winter, you need to have big enough plants going into the winter, to provide sustainable harvests (once a week in November and February and more in spring, plus maybe once a month in December and January)
Overwintered Vates kale.
Photo credit Twin Oaks Community

Various Fall Brassica Crops

In the summer we try to have a No Visible Brassicas Month to break the lifecycle of the harlequin bugs. Once our spring kale is finished, the spring cabbage gathered in, and the spring broccoli mowed down, the only brassicas are seedlings hidden under insect netting. Our hope is to starve out the harlequin bugs or at least deter them from making too many more.

We sow other fall outdoor brassicas a bit later than cabbage and broccoli. These get transplanted from our netting-covered nursery seedbeds, to our raised bed area which is more accessible for winter harvesting and more suited to small quantities.

Asian Greens

Outdoors we grow Senposai, Napa Chinese cabbage and Yukina Savoy. We have also sometimes grown tatsoi and komatsuna. Note that senposai grows quite large – give it similar spacing to collards.

We sow Asian greens for outdoors in the last week of June and first week of July, aiming to eat them before we start harvesting the ones in the hoophouse, which feed us all winter. We use Asian greens outdoors as quick-growing greens to fill the gap before our main fall greens (spinach, kale, collards, cabbage, broccoli) are ready to harvest. We don’t grow a lot outdoors.

If you don’t have a hoophouse, you can sow for outdoors later into the fall than we do, to get a longer harvest season than you otherwise would. And you certainly can direct seed them.

Yukina Savoy outdoors in December, after several nights at 16-17°F (-8 to -9°C)
Photo Kathryn Simmons

Collards

We sow collards in the first two weeks of July and transplant the bare-root transplants from the nursery bed when they are 3-4 weeks old. We plant at 18” (46 cm) in the row, with rows 12” (30 cm) apart. (if you grow a large kale, you might want similar spacing. Our Vates kale is small)

Morris Heading collards.
Photo Kathryn Simmons

Brussels sprouts

are rather a challenge in our climate, and not worthwhile. We have worked on finding the best variety (Oliver) and timing for our situation. Harvest timing is critical, as Brussels sprouts will not overwinter here.

Cauliflowers

are a tricky crop for us too. Be sure to check the “days to harvest” for each variety (they vary widely) and sow at a realistic date to get a crop before too many frosts endanger the curds. The number of days quoted for fall varieties of cauliflower already allows for the expected rate of growth at that time of year, so the 14 days for slower growth isn’t a factor. However, cauliflower is more tender, so allow for the possibility of a fall frost earlier than average.

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

Kohlrabi

We sow Vienna kohlrabi mid-July and transplant early August at 8” (20 cm) apart in the row, with 9-10” (23-25 cm) between rows. Later sowings (up till early September) would also work for the fast maturing varieties. Superschmelz Kohlrabi (60 days from transplanting) can also be summer sown for fall harvest. It produces 8-10” (20-25 cm) bulbs, which remain tender and an attractive globe shape.

Kale

We direct-sow two neighboring beds of kale on each of 8/4, 8/10, 8/16 and then carefully thin them, leaving one plant every 12” (30 cm). These plants grow quicker than transplants, as they have no transplant shock. Meanwhile, if we have gaps, we use the carefully dug thinnings from those beds to fill them. We want a lot of kale, and there isn’t time to transplant it all. Dividing up the sowings lets us focus on watering just one pair of beds at a time. Vates kale is the hardiest variety we have found, although I’d love to find a taller Scotch curled variety that could survive our winters (Winterbor does not survive as well as Vates).

An outdoor bed of young Vates kale Photo Kathryn Simmons

Rooty Brassicas

Radishes, rutabagas and turnips are also brassicas, but I won’t say more here. look in the further resources.

Brassica Aftercare

Brassicas started in hot conditions do not usually bolt if they have enough water.

 

Brassica seedlings under ProtekNet in August.
Photo Pam Dawling
  • Protect seedlings and the new transplants with insect netting if you have brassica leaf pests (most of do!) You can remove the netting when the transplants are well established, or leave it on.
  • Use shadecloth to keep greens cool in hot weather, or plant them in the shade of other plants.
  • To keep crops in good condition later into the winter, use rowcover. I recommend thick Typar 1.25oz rowcover, which provides 6F degrees of cold protection. I wouldn’t spend the money on anything thinner, it’s too frustrating! We do not normally use rowcover in the winter for kale and collards, as they will survive without. In harsh winters we lose the collards.

Cultivation is a simple matter of hoeing, weeding, watering as needed, and watching for pests.

Further Fall Brassica Information

Time to sow fall broccoli and cabbage

Broccoli head after rain
Photo Wren Vile

We are almost at a big turning point of the growing season, the Summer Solstice, the longest day. We know that day-length influences plant growth, and that after the Solstice, some crops will gradually take longer and longer to reach maturity (others will bolt). Crops more influenced by temperature (like sweet corn) will continue to mature faster while the summer temperatures rise.

Here in central Virginia, most brassicas are planted in spring and again in fall. Unless your broccoli keeps going all summer, consider sowing a new crop for fall. Although it can be hard to think about sowing seeds in mid-summer, it’s very worthwhile to grow fall brassicas because as they mature in the cooler fall days they develop delicious flavor, while weeds and pests slow down. These crops need little care once established. The most challenging part is getting the seedlings growing well while the weather is hot. However, unlike some cool weather vegetables such as spinach and lettuce, brassica seeds actually germinate very well at high temperatures. The ideal is 77-85°F (25-29°C), but up to 95°F (35°C) works. Given enough water, summer seedlings will emerge in only 3 days. Once they have emerged, the challenge begins. As well as temperature and moisture in the right ranges, the seedlings need light (very plentiful in mid-summer!), nutrients, good airflow, and protection from bugs. We deal organically with flea beetles, Harlequin bugs, and sometimes cabbage worms. Our main defenses are farmscaping, and netting (and previously, rowcover).

My book Sustainable Market Farming, has a chapter devoted to Broccoli, Cabbage, Kale and Collards in Fall.

Fall broccoli patch.
Photo Kati Falger

Timing sowing of fall broccoli and cabbage

The number of days to harvest given in seed catalogs is usually that needed in spring – plants grow faster in warmer temperatures. To determine when to sow for fall plantings, start with your average first frost date (as an indicator of cooling temperatures), then subtract the number of days from seeding to transplant (21-28), the number of days from transplanting to harvest for that variety (given in the catalog description), the length of harvest period (we harvest broccoli for 35 days minimum), and another 14 days for the slowing rate of plant growth in fall compared to spring. For us, the average first frost is 10/14-10/20, and we sow 53-day broccoli 21+53+35+14 days before 10/14, which is 6/13-6/19.  The last date for sowing broccoli and cabbage is about 3 months before the first fall frost date. In our case that means July 14–20.

Planning and crop rotations for fall brassicas

Our rotation plan shows us a long way ahead how many row feet of fall broccoli and cabbage we can fit in. By the time we order our seeds in the New Year, we know roughly what we expect to grow. In February we draw up a spreadsheet of how much of what to sow when.

Because fall brassicas are transplanted in summer, it’s possible to grow another vegetable crop, or some good cover crops, earlier in the year. An over-wintered cover crop mix of winter rye and crimson clover or hairy vetch could be turned under at flowering, and be followed by a short-term warm weather cover such as buckwheat, soy or cowpeas. Brassicas are heavy nitrogen consumers. To minimize pests and diseases, don’t use brassica cover crops.

Systems for growing fall broccoli and cabbage transplants

The same systems you use for growing transplants in spring can also work well for fall. It can help to have your plants outside on benches, above the 3’ (1m) height of flea beetles. A shade-house might be ideal too. Direct sowing, in “stations” (groups of several seeds sown at the final crop spacing), works for small areas.

We use an outdoor nursery seedbed and bare root transplants, which suits us best. The nursery bed is near our daily work area, so we’ll pass by and water it. Having the seedlings directly in the soil “drought-proofs” them to some extent. They can form deep roots, and do not dry out so fast.

For the seedbeds we use ProtekNet on wire hoops. Choose the mesh size carefully. One with small holes is needed to keep flea beetles away – 25 gm or 47 gm. Overly thick rowcover can make the seedlings more likely to die of fungal diseases in hot weather – good airflow is vital.

Sowing fall broccoli and cabbage

Brassica seedlings growing outdoors under insect netting.
Photo Pam Dawling

 Our rough formula for all transplanted fall brassicas is to sow around a foot (30 cm) of seed row for every 12-15’ (3.6-4.6 m) of transplanted crop row. We aim for 3 seeds per inch (about 1 cm apart). This means sowing 36 seeds for 10 plants transplanted on 18” (46 cm) spacing. And we do that twice (72 seeds for 10 plants!), in two sowings a week apart, to ensure we have enough plants of the right size.

Fall Brassica Schedule

Our seedbeds have an 8-week program – see the spreadsheet above for examples of our timing, quantities and varieties. I like to have a regular afternoon every week to grow the transplants. If you’re growing for fewer than 100 people, you won’t need a whole afternoon! Each week after the first week, we also weed the previously sown plants, and thin to 1” (2.5 cm) apart. Then we check the germination, record it, and resow if needed to make up the numbers.

 

Bare root brassica transplants under Proteknet.
Photo by Bridget Aleshire

Transplanting fall broccoli and cabbage

We transplant most brassicas at 4 true leaves (3-4 weeks after sowing at this time of year). It is best to transplant crops at a younger age in hot weather than you would in spring, because larger plants can wilt from high transpiration losses. If we find ourselves transplanting older plants, we remove a couple of the older leaves to reduce these losses.

We transplant 6 days a week for an hour and a half or two hours in late afternoon or early evening, for 2-3 weeks. We water the soil in the plot an hour before starting to transplant. It is very important at this time of year to get adequate water to the plants undergoing the stress of being transplanted. Likewise, good transplanting technique is vital. Water a lot more than you do in spring. If you have drip irrigation, you can easily give a little water in the middle of each day too, which will help cool the roots.

One of our impact sprinkler tripods, in a broccoli patch.
Photo Pam Dawling

We transplant broccoli and cabbage in 34” (86 cm) or 36” (91 cm) rows, which is wider than necessary. Beds or paired rows can fit more plants in the same space, while still allowing room to walk. We hammer in stakes along the row, and attach ropes between them. These both mark the rows for transplanting, and support the netting that we use after transplanting to keep the bugs off. An 84” (2.1 m) width netting can form a square tunnel over two crop rows, giving good airflow. Wire hoops are an alternative. Watering the soil before planting, as well as afterwards, helps survival during the hot summer days.

Aftercare of fall brassicas

About a month after transplanting the broccoli and cabbage (late August-early September), we remove the netting, stakes, ropes and the sticks we use to hold down the netting edges, then hoe and till between the rows. Next we broadcast a mix of mammoth red clover, Ladino white clover and crimson clover. We use overhead sprinkler irrigation to get the clover germinated, and it also helps cool the brassicas. The ideal is to keep the soil surface damp for the few days it takes the clover to germinate. Usually watering every two days is enough. We may replace the netting if pest pressure seems bad.

 

Fall broccoli undersown with a mixed clover winter cover crop.
Photo Nina Gentle.

If all goes well, we keep the clover growing for the whole of the next year, mowing several times to control annual weeds. You could, instead, till in the clover in late spring or early summer to plant a food crop then.

Harvesting fall broccoli and cabbage

We harvest all our brassicas three times each week, and take the produce directly to our cooler.

Broccoli side shoots.
Photo Nina Gentle

Our main broccoli harvest period is 9/10-10/15, with smaller amounts being picked either side of those dates We like our broccoli heads to get as large as possible (without opening up) before we harvest. We test by pressing down on the head with our fingertips and spreading our fingers. We harvest as soon as the beads start to “spring” apart. This may be a little late for other growers. We also look at the individual beads and aim to harvest before the beads even think about opening. We cut the stem diagonally to reduce the chance of dew and rain puddling, which can cause rotting of the stem. Later we harvest the side shoots, until they are too small to bother with.

A storage cabbage, with curled-back leaf on the head, showing maturity.
Photo Bridget Aleshire

Cabbage heads up from 9/25 and holds in the field till late November. Cabbage is mature when the outer leaf on the head (not the outer plant leaves which are left in the field) is curling back on itself. For storage cabbage, we set the cut heads upside down on the stump, in the “basket” of outer leaves, and come back an hour later to gather them into net bags. This allows the cut stem to dry out and seal over, improving storability.

If you are already looking ahead to the fall, see my post Fall and Winter Vegetable Growing, Harvest and Storage, for lots of links to more info on season extension into cold weather; fall and winter vegetable harvests; and fall and winter vegetable storage. I will write more about other fall brassicas in the near future.

Big frosty fall cabbage.
photo Lori Katz

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.