Spring Lettuce Transition

Our first outdoor lettuce bed in May.
Photo Wren Vile

We grow lettuce to harvest year round, here in central Virginia. From the end of April into November, we harvest lettuce heads outdoors, from our raised bed area. From October to early March we harvest outer leaves from leaf lettuces and romaines in our solar greenhouse, and in our solar-heated double-layer hoophouse from October to April. From mid-November we harvest salad mixes containing lettuce from our hoophouse. From 4 December to late May we have baby lettuce mix from the hoophouse. Note that we have overlaps at both spring and fall transitions. We’re approaching the spring transition, and that is what I am going to focus on in this post.

 Our Winter Hardiness Zone in central Virginia is 7a, which means our annual minimum temperature averages 0°F to 5°F (-18°C to -15°C).  Our average date of the last spring frost over the past 14 years is April 29 (later than 5/13 one year in 10).

Flats of lettuce transplants in our cold frame in April.
Photo Pam Dawling

More About Growing Lettuce

See my post Lettuce All Year in a Changing Climate, which includes links to my slideshow about growing lettuce year round, and our updated Lettuce Varieties list and Lettuce Log (planting schedule). It also includes keys to succeeding with year-round lettuce (dates for succession planting) and what causes bolting.

I have lots of posts about growing lettuce! Here are some of them:

Early Lettuce Production See this post for details of growing lettuce transplants in flats in our greenhouse.

Cold Tolerant Lettuce – In the 2017-2018 winter we had some extremely cold weather, with outdoor night-time temperatures of -3°F (-19°C) two nights, followed by -8°F (-22°C) 6 and -9°F (-23°C). Our guideline is that if we expect the night-time low to be 8°F (-13°C) or lower outdoors, we use rowcover in the hoophouse. It wasn’t enough to save all the lettuce. See this post for which varieties survived.

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

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

And I have a whole year of Lettuce for the Month posts. See here for the overview. These posts are mainly about our favorite varieties for each time of year.

Head Lettuce Transplanted Outdoors

From February to November/December, we grow lettuce outside from transplants. Transplanting gets a head start on weed control, which is important all the way from planting out to a couple of weeks before harvest. Don’t waste time hoeing lettuce you will be harvesting next week. I generally find that if we hoe once, a couple of weeks after transplanting, that is all the weed control we need at the fast-growing time of year.

From mid-January until mid-March we sow in flats in the greenhouse, with heating for the January-March sowings, to get the seeds germinated, then good old solar energy to grow them to transplanting size. We spot the seedlings out to give the plants more space, and harden off the flats of transplants in our cold frame for two weeks before planting them in the garden. The first few plantings will get rowcover after transplanting, to protect the young plants from cold and speed up the growth rate. March 9 is our goal for transplanting our first sowing (January 17) outdoors. January 17 to March 9 is 52 days, a very long time for the seedlings to grow to transplant size! We hope to harvest that first lettuce as heads in late April.

During April we put the seed flats in the greenhouse without extra heating, as temperatures in the greenhouse are warm enough to germinate the seeds. Growth speeds up, and in warm weather we transplant three weeks after sowing. The intervals between one transplanting date and the next decrease from 9 days in spring to 5 or 6 days in summer. We transplant 120 lettuce from each sowing – about one week’s worth for 100 people.

Swordleaf lettuce, and an unnamed romaine with radishes. Photo Bridget Aleshire

Soil Temperatures for Lettuce Germination

The soil temperature range for germination of lettuce seeds is 35-85°F (2-29°C), with 40-80°F (4-27°C) being the optimum range and 75°F (24°C) the ideal. At 41°F (5°C) lettuce takes 15 days to germinate; at 50°F (10°C) it takes 7 days; at 59°F (15°C) 4 days; at 68°F (20°C) only 2.5 days; at 77°F (25°C) 2.2 days. Then the time to germination increases: 2.6 days at 86°F (30°C); after that it’s too hot. A soil thermometer soon pays for itself and saves lost crops and frustration.

Summer Lettuce Nursery Seedbed with Concept, De Morges Braun, New Red Fire and Loma lettuces.
Photo Bridget Aleshire,

Bare-Root Transplanted Lettuce in Summer

From May to late September we use an outdoor nursery seedbed and do bare-root transplants (with heat-tolerant varieties). The soil temperature does not vary as much as the air temperature, and  we no longer worry about cool nights.

If it’s too hot for lettuce seed to germinate, you can find a cooler place (put a seeded flat in a plastic bag in the fridge or on the concrete floor in the basement). Or cool down a small part of the world. From June we put shade-cloth over the lettuce seedbed, and only sow in the evening. In July and August, we water the sowed seedbed with freshly drawn cold water, line up ice cubes along the seed rows, and cover with shade cloth.We make sure to keep the seedbed damp, using cold water each time.

See Using ice to germinate lettuce seed in hot weather

From July to September we sow lettuce every 5 days! See Success with summer lettuce. Of course, transplanting that lettuce in hot weather takes care too. We do that late in the day, and water as we go. We cover the transplants with hoops and shade-cloth, and water daily until they are well established. We stop sowing for outdoors on August 29.

If using a nursery seed bed, you can put ice cubes on top of rows of seeds in hot weather to help cool the soil.
Photo Bell Oaks

Lettuce After Summer Ends

From September 11-17 we sow lettuce in a nursery seedbed to transplant in our greenhouse, and on September 15 and 24 to transplant in our hoophouse. This is our fall transition and I’ll write about that when the time comes.

Preparing for sweet corn

Our first sweet corn of the season. Bodacious
Photo Pam Dawling

Preparing for sweet corn

It’s too early for us to be planting sweet corn, but not too soon to be planning, preparing and thinking about it!

Crop Rotations and Cover Crops

Rotation Pinwheel Sus Mark Farm

If you don’t already have a crop rotation plan, this is the time to put one into place, especially if a lot of your ground is taken up with sweet corn every year! Our sweet corn occupies a lot of our space, so we pay attention to crop rotation. Corn is the only crop in the grass family that we grow, so this is not hard. We keep two or three years without corn between the corn years. Here’s the crop and cover crop sequence for each of our six sowings:

Sowings 1 & 2: The winter before the corn, we have a winter-killed cover crop of oats, (or sometimes a clover patch which has been growing all the previous year). Half the patch of this early corn is followed by oats in August and then garlic in early November. The other half gets oats and soy in August, to be winter-killed. This area will be easy to work up in early spring for our broccoli and cabbage.

Sowings 3, 4, & 5: The previous winter cover crop is winter rye or wheat with crimson clover (if we sow before 10/14) or winter rye or wheat with Austrian winter peas if after 10/15. The corn is followed by more rye or wheat and crimson clover in October. The following year we will plant potatoes here in June. The clover will have plenty of time to reaching flowering and therefore have plenty of nitrogen nodules on the roots.

Cover crop of winter rye, hairy vetch and crimson clover.
Photo Kathryn Simmons

Sowing 6: The previous winter cover crop is winter rye and Austrian winter peas. We undersow this corn with oats and soy. We mow high after harvest, and leave the oats and soy to grow until winter-killed. This patch is easy to prepare for our potatoes in March.

Late sweet corn undersown with oats and soy beans for a winter-killed cover crop. Photo Kathryn Simmons

For the later sowings of sweet corn, a good stand of a preceding winter cover crop mix including legumes can provide all the nitrogen the corn needs (100-125 lbs/acre; 112-142 kg/ha). The nitrogen nodules on the roots contain the maximum nitrogen when the legume reaches its flowering point, so this method doesn’t work for early sowings.

 No-till planting into strips tilled in a white clover living mulch sounds good but has been found tricky. Jeanine Davis addresses this in NCSU’s Organic Sweet Corn Production. The clover can out-compete the corn, become invasive and hard to get rid of. Soil temperatures will be lower (a disadvantage in spring) and slugs and rodents may increase. Trials of sowing corn into rolled and crimped hairy vetch are underway.

Undersowing (interseeding) cover crops such as white or crimson clover into the corn at the V5 or V6 stage is more successful. Ensure good seed-to-soil contact. The clover grows after the corn dies.

Some growers undersow with forage brassicas at last cultivation. Research shows this does not reduce corn yields. The forage can be harvested after the sweet corn harvest finishes.

Caring for Sweet Corn

Young sweet corn plants after imperfect hoeing.
Photo Pam Dawling

Never allow soil in corn plantings to dry out, especially with close planting. You might need more than 1” (2.5cm) per week for maximum productivity, although corn is more drought-tolerant than some crops. The most important times for watering are silking (when the silks first become visible) and while the ears are filling out. We use overhead irrigation for corn, which works well to also water undersown cover crops.

Corn plants closer than 8” will compete with each other, so be sure to thin. People used to recommend removing the suckers that came from the base of the plant, thinking it led to higher yields. This has been tested, and in fact it can damage plants and possibly even reduce yields. (Reports from Clemson and Colorado State).

Sweet corn needs cultivating at least twice, at two weeks and four weeks after sowing. Even better are four rounds: at 7, 14, 21 days and finally one around 35 days when plants are 18-20” (45-50cm) high. Corn is shallow rooted so avoid deep cultivation. We use a walk-behind BCS tiller, followed by hoeing (and thinning at the first cultivation).

Young sweet corn plants. To the right are ropes to mark rows for the next corn sowing.
Photo Bridget Aleshire

Each time we sow sweet corn, we wheel hoe or till between the rows of the previous planting, hoe and thin the plants to 8-12” (20-30 cm). We also till between the rows of the corn planting before that, hoe, and sow soybeans. Although they don’t supply the highest amount of nitrogen compared to other legumes, they are cheap, quick, somewhat shade tolerant, hinder weeds, and withstand foot traffic during harvesting.

While harvesting the corn we pull out any pigweed that has somehow survived our earlier efforts. Pigweed puts out its seeds in one big burst, so pulling up enormous pigweed is worthwhile, if it hasn’t yet seeded. Our soil has improved over the years, so it is now possible to uproot the 5ft (1.5 m) pigweeds. Sometimes we have to hold the corn plant down with our feet, but we do almost always succeed in getting the weeds out.

Silver Queen sweet corn with wilting pulled pigweed amaranth. Photo Kathryn Simmons

Flame-weeding can be used after sowing before the corn emerges, or after the crop is 2” (5cm) tall, using a carefully directed flame. See ATTRA Flame Weeding for Vegetable Crops

Sweet Corn Growth Stages

It is helpful to understand corn growth stages so that you know when the plant is most susceptible to damage, and when to take action. Corn growth stages are divided into vegetative (V) and reproductive (R). Stages are determined when at least 50% of the plants have reached or are beyond a particular stage.

Vegetative stages begin at emergence (VE), and each leaf with a fully developed collar is a new stage. Leaves within the whorl, not fully expanded and with no visible leaf collar, are not counted. Most sweet corn hybrids produce 18-21 leaves. Vegetative growth takes about 55-60 days after emergence. V3 (three leaf collars) begins 2-4 weeks after VE, and plants switch from using kernel reserves to photosynthesis and roots for nutrients.

Around V4, broadleaf weeds will stunt yields and should be removed. By V5, the numbers of potential leaves and ears are determined. Plants are 8-12” (20-30 cm) tall and the growing point may still be underground. Tillers (suckers, branches that grow from the lower five to seven nodes) appear.

V6-V8 – Beginning 4 to 6 weeks after VE, the growing point emerges above the surface, making the crop susceptible to frost, hail and winds. Beginning at about V6, the lower leaves may fall off naturally. At V7, rapid growth begins, and the number of kernel rows is determined. The number of potential kernels per row begins is set between V7-V16. By V8, the plant reaches 24” (60 cm) tall.

V9-V11 – At V9, tassels (not yet visible) and ear shoots are developing. New leaves appear every 2-3 days

V12 – The plant is 4ft (1.2 m) tall or more. Nutrients and water are important from this stage until the start of the R stages. The leaves are full-sized and about half are exposed to sunlight. “Brace roots” develop and the number of kernels per ear and size of the ear are set. Kernels can be damaged by insects and hail.

V15 – The plant is two weeks away from silking. Tassels are almost full-sized, but still hidden. Moisture and nutrient shortages now result in shorter ears and lower yields.

VT – Beginning 9-10 weeks after emergence, good pollination is essential to develop the kernels. Tassels are fully visible and silks emerge in 2-3 more days. Pollen shed begins, continuing for 1-2 weeks. Hail can be very damaging at this stage. Vegetative stages end when the corn develops a tassel (male flower). It takes about 20 days from tasseling to ripe.

Sweet corn growth stages. University of Illinois Extension

R1 – The plant has silks outside of the husks and is at its most vulnerable. Environmental conditions can greatly affect pollination. The worst is drought, which dries the silk out, reducing its ability to collect pollen falling from the tassels.

R2 (“Blister”) stage – The kernels are filled with clear liquid. About 12 days after silking, the silks darken and dry out. Stress (especially drought) can cause kernels to abort.

R3 – Milk stage – About 20 days after silking, kernel fluid turns milky, as starch accumulates. The effects of stress are not as severe after this stage, but can still lead to shallow kernels.

R4 – Dough stage – About 26 days after silking, the kernels have a dough-like consistency. Stress can produce scrawny kernels.

The dent stage (R5) and full maturity (R6) will only happen if you leave the plant to produce seed.

Corn growth stages can be estimated using corn growing degree days (GDD), accumulated daily from the date of planting. GDD are calculated by averaging the max and min temperatures in a 24-hour period. 50°F (10°C) is subtracted from that average temperature to give the GDD for the day. A Corn GDD Tool is available at the High Plains Research Climate Center. Stress, especially drought, can affect growth and GDD alone may not provide an accurate estimate of growth stage.

Workhorse Crops for April

 

Garlic beds in April. Cabbage under rowcover on the left, strawberry beds on the right. Photo Kathryn Simmons

This is the last month in my 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 weather conditions.

Here are links to the other 11 months:

Spring is here. April is a busy month for sowing and transplanting! First the rest of the cool weather crops, then the first of the warm weather crops. Our average last frost (over the past 14 years) here in central Virginia is April 29. We reached 12 hours of daylight on the March 20 Equinox, and the days lengthen until the summer solstice.

Gentry yellow squash newly transplanted into our hoophouse, with a friendly wood sorrel!
Photo Pam Dawling

In our hoophouse we are transplanting squash, cucumbers, and peppers in April. Those crops will occupy the centers of the beds, before taking over the whole width. By that time, we will have harvested any remaining winter salad crops, and the spinach we transplanted in early March. Our greenhouse and coldframe are packed with transplants.

Workhorse Crops to Plant in April

Newly emerged beans (in rather dry soil).
Photo Pam Dawling

Beans

We sow our first green beans April 24, around our last frost date. We choose two reliable varieties, Provider and Bush Blue Lake. Or Contender. There are varieties that are more delectable and tender, like Jade, but those are less cold-tolerant, and so not good for the first planting. We soak the bean seed overnight before planting.

We sow 2 rows in a 4ft (1.2 m) wide bed, with the rows about 16” (40 cm) apart. Seeds about 3” (7 cm) apart, closer if they are leftover from last year. Bean seed does not germinate well if older than that.

We use inoculant to help the nitrogen-fixing bacteria get started. We probably have plenty in the soil by now, but early in the year, everyone is a bit slower to get moving!  We cover the beds with rowcover until the weather has settled warm.

We make 6 sowings of beans. Our sowing dates are 4/24, 5/8, 5/24, 6/8, 6/24 and 7/8. The intervals between plantings are 14, 16, 15, 16 and 14 days. This schedule has got a bit off-course and has a much earlier end date than necessary. A better set of dates would be 4/20, 5/11, 6/1, 6/22, 7/13 and 8/3, at intervals of 21 days. The rate of maturity of beans does not vary much with temperature.

Cabbage

We are not growing any storage cabbage this spring, due to those infamous staff shortages everyone is struggling with. If we had sown some in early February, we would be transplanting them April 1, and covering the bed with ProtekNet for as long as possible to keep the bugs off. If we used rowcover when we first transplanted them, we remove it in April to use elsewhere (broccoli). Cabbage to store for the summer can be a great way to have greens other than chard during hot weather.

A tidy bed of young carrots. Photo Kathryn Simmons

Carrots

From April we switch to sowing one bed per month until August. We sow our fifth carrots April 10, and our sixth in May. The April sowing takes about 11 days to germinate, depending in on the soil temperature. Our standard practice is to flame weed carrots before the seedlings emerge. In April we have lots of weeding and thinning of carrots sown earlier.

Chard

We sow chard (and leaf beet, the type of chard closest to spinach) on March 24, and transplant on April 22, with two rows in a bed, close together down the middle, to leave the paths free for us. Chard will be our main summer leafy green after the brassicas have all bolted. We usually do a mix of a multicolor type for beauty, Fordhook Giant for reliability and productivity, and Perennial Spinach leaf beet as insurance. The leaves are smaller, making it slower to pick, but it does taste more like spinach than any of the other chards, and it is very resilient.

Young sweet corn plants.;
Photo Bridget Aleshire

Sweet Corn

We sow our first sweet corn on April 26, being sure to choose varieties such ads Bodacious, with good cold-soil emergence. We also sow some Speedling flats on the same day, and float them in a n outdoor tank, as a care-free way of having some backups to transplant as replacements for casualties if a late frost strikes. Our harvest goal with our fist sowing is July 4-18. Our 6 sowings of sweet corn are scheduled to give us an even continuous supply, with a new planting coming on-stream every 15 days. We harvest three times a week

Potatoes

Potatoes can be planted here in April, but we prefer to divide our planting in two, half in march, half in June. Click the link for more about every stage of potato growing .

A row of squash plants with ProtekNet to keep bugs off until flowering.
Photo Pam Dawling

Summer Squash/Zucchini

We transplant our first outdoor summer squash and zucchini (as well as the ones we grow earlier in the hoophouse). We start them in the greenhouse March 27, in 6×12 Speedling flats. Those cells are bigger than the Winstrip 50 cells. We like Tender Gray 42d zucchini, a light-colored Middle Eastern variety, and Zephyr 54d yellow squash with distinctive green tips. We transplant them 4/21 with rowcover or ProtekNet to keep the striped cucumber beetles away. Other squash pests (Squash bugs, Squash Borers) are not such a problem for us. From the second sowing onwards, we direct sow outdoors, as the soil has warmed up by then. We often transplant or sow nasturtiums in among the squash (or the cucumbers) to deter cucumber beetles. We also enjoy the flowers.

Greenhouse sowings for later transplanting outside, and other greenhouse work

In April in the greenhouse, we sow our watermelons, and paste tomatoes if we’re growing those, and some non-workhorse crops, of course.

Watermelon transplants in a Winstrip plug flat. Watermelons give earlier harvests from transplants, and plants in plug flats transplant easier then from open flats.
Photo Pam Dawling

Watermelon

Watermelons need warm soil. We’re not growing any this year. Our method has been to sow them in Winstrip 50-cell trays in the greenhouse April 26, and transplant them into biodegradable plastic mulch (with drop tape under it) May 11. (We use 3’ (1 m) spacing with rows 66” (1.7 m) apart. We rowcover the transplants for 3 weeks, until flowering, and then remove the covers to allow pollination to happen.)

Winter Squash.

Winter squash is normally such a lovely, easy crop! Direct sow, water, thin, hoe, till between the rows until the vines run, then ignore them (apart from watering) until September. We have mostly grown Moschata types as they have the best resistance to squash bugs, and they store really well. Our favorites include Waltham butternut, Cha-cha Kabocha, Cheese Pumpkins, Jarrahdale squash and the giant Tahitian Butternut. We direct sow May 26, but if there are particular challenges with constant rain preventing us preparing the soil, we have transplanted, from cells sown in late April.

Potting Up

Pepper transplants in our greenhouse. Photo Kathryn Simmons

We pot up the peppers and eggplant for transplanting outdoors in May. Eggplant needs to be kept above 55°F (13°C), peppers above 50°F (10°C) and tomatoes above 45°F (7°C).

Sweet Potato Slips

Also, we continue cutting sweet potato slips. I covered growing sweet potato slips last week.

Workhorse Crops to Plant in the Hoophouse in April: Squash, Cucumbers, Peppers

North edge bed in our hoophouse flagged up for digging holes to plant peppers.
Photo Pam Dawling

We plant one bed each of these crops, measuring and digging holes 2’ (60 cm) apart down the center of the bed, and adding a shovelful of compost to each hole. We do not clear the winter crops from the beds before transplanting the new crops. We value the extra month of greens we can harvest this way. When the new crops are small, they don’t need the whole space, and I’ve even thought that the slight shade from the greens helps the new transplants settle in.

We grow a bush (non-vining) cucumber Spacemaster, and two early squashes, sometimes Golden Glory zucchini and Zephyr. The bell peppers are Lady Bell, Gilboa (orange) and Revolution, all fairly early, big, thick-fleshed  and tasty.

Hoophouse Tomatoes

In April we install the posts for tomatoes (hopefully we won’t need to use rowcover at nights any more, and start string-weaving. We use the Florida string-weaving (or basket-weaving) technique to support our plants. More about that task in future.

Workhorse Crops to Harvest in April

Asparagus

Asparagus photo Kathryn Simmons

The asparagus harvest season usually begins for us in early April. Well prior to that date we root out early weeds.  Then we fertilize with fish meal and greensand or a complete fertilizer, or add a thick layer of rich compost (if we did not do this in the fall), spread over the whole bed.  Next, mulch to a depth of at least 4” (10 cm) for weed control, with wood chips, wood chip horse bedding, sawdust, straw or old hay (although hay may include weed seeds).

I recommend snapping asparagus spears at ground level – cutting them below the soil surface risks damaging emerging spears. Harvest in the early morning, as the spears are easier to snap before they warm up. Snapped asparagus is almost all tender and usable – the tough lower ends remain in the soil. If you expect a frosty night, harvest all spears, regardless of size, as they will otherwise freeze and be wasted. We have sometimes done a second (afternoon) harvest, if we’ve noticed a cold forecast. During the harvest season, ensure the asparagus gets 2” (5 cm) water each week.

At the beginning of the season, when the weather is cooler, spears can grow to 9-10” (22-25 cm) before ferning out, but in warmer weather, they will open out at a shorter height.  So, expect to harvest shorter spears in warmer weather. To keep life simple, we tell our crew to pick any spears 7” (17 cm) or taller. You may prefer to change the required length according to the temperature. Harvest anything of the right length, regardless of thickness. For pest management, we pick and later discard skinny, tough spears, and any that are ferning out. (Slender stems are not more tender than large ones, quite the contrary.) We harvest the entire patch every single day as a way of controlling asparagus beetles – no spears are left long enough to leaf out, and beetle eggs are removed (on the spears) and cannot hatch. The eggs are harmless, and can be washed off after harvest by spraying with water, or tub-washing.

We harvest into short buckets so that the spears will be standing on end when the bucket is upright. We add a small amount of water, to keep the spears fresh, and hurry the buckets to a cooler at 34-40°F (1-5°C).

Asparagus photo by Kathryn Simmons

First year after the planting year

Trials now show that asparagus yields more long-term if it is lightly harvested for 2-4 weeks in the first year after the planting year, in contrast to previous directions to wait 3 or 4 years. Stop harvesting after 4 weeks at the most, as soon as the thickness of most of the spears is less than the size of a pencil.

After the first (short) harvest season, let the spears grow tall and fern out. The photosynthesis of the ferns feeds the crowns and strengthens them for next year’s growth. Established asparagus is fairly drought-tolerant, but immature plantings need 1” (2.5 cm) of water each week. By the fall ferns will be 4-5’ (1.2-1.5 m) tall. Apply compost every year in the fall or winter.

Second year culture

In late February or March, we weed, spread compost (if we didn’t do it in the fall) and mulch to a depth of at least 3” (7.5 cm). We harvest for perhaps 5 or 6 weeks in the second year after the planting year. Stop picking when the thickness of most stems is less than a pencil. By the end of this second season the asparagus ferns will likely reach a height 6-8’ (1.8-2.4 m).

Third year and future years

Weed, spread compost, mulch, harvest and irrigate, weed, mulch. Pick asparagus for perhaps 6 weeks in the third production year, stopping when the spears are thin. By the fifth year you should reach a maximum harvest season of 8-9 weeks.

Chard – our hoophouse chard is growing at a good rate. This winter we started late, and so we have only been able to harvest the chard small, for salad mixes. In April we will get leaves large enough to cook.

Bright Lights chard.
Photo Pam Dawling

Collards and Kale can be harvested all month (over-wintered plants) until they start bolting. The spring-planted ones outdoors are ready from mid-April.

Overwintered Carrots and Cabbage are a possibility some years, but not this one!

Garlic scallions are still available to harvest here. We dig the plants once the leaves have reached at least 7” (18 cm). Wash and trim, cook and enjoy! Some years we have made a big planting, and it has provided for us into May (when they will start to bulb).

Hoophouse Workhorse Harvests in April

Our Red and White Russian kales are now producing well. These are Siberian-type kales, that keep growing (a bit!) in cold weather. We harvest the outer leaves and stand them on end in a bucket in a little water. The wilt very easily, so we try to keep them in the shade and get them to the cooler promptly.

Workhorse Crops from Storage in April

In April we can eat cabbage carrots, garlic, potatoes, sweet potatoes, and winter squash from storage, while they last. We do still have potatoes, sweet potatoes and butternut squash. Also we have frozen summer goodies, and pickled things, sauerkraut, pickled beans, and canned goods like salsa.

Workhorse Crops Special Topic for April: Rowcover

A rowcovered bed of turnips.
Photo Bridget Aleshire

Use rowcover to keep new transplants outdoors protected from cold until they are acclimated and /or the weather warms up. In the hoophouse in April we use rowcover on possible frosty nights, to protect our new tender crops.

Rowcover is lightweight, easy to use, and easy to store. Its biggest challenge is that you need to hold down the edges with bags of rocks or sand, plastic jugs of water, or metal or wooden stakes rolled in the edges, to stop it blowing open or even blowing away!

To protect against cold, you need thick rowcover. We think polypropylene rowcover lasts longer and is tougher than polyester (Reemay). We like Dupont Xavan 5131 (aka 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.

Thinner types are made to protect from insects – if you already have thin rowcover You can double it up for cold weather use. Thinner types are very fragile and are easily torn by inexperienced helpers.

Double hoop system for winter rowcover.
Pam Dawling

Hoops keep rowcover from sticking to frozen leaves and reduce abrasion. For winter we made double wire hoops. 9- or 10-gauge wire inner hoops, 22 gauge outer hoops, every 6ft (2 m) down the length of the row.

See Workhorse Crops for March for info on Predicting Frost

Blueberries.
Photo Marilyn Rayne Squier

For my next series of crops for the month, I’m planning to write about small fruits (berries and melons)

Book Review: The Ecological Gardener by Matt Rees-Warren

Book Review: The Ecological Gardener: How to create Beauty and Biodiversity from the Soil Up, by Matt Rees-Warren, published by Chelsea Green. 200 pages, paperback, $24.95

This is a lovely book for those wanting to make their backyard or homestead into an area more aligned with nature. It includes fruit trees and vegetables but these are minor themes in the book. It’s a guidebook to understanding your land, and working with the features of the space – slope, water, soil, light and shade. It includes constructing rainwater catchments, making compost, encouraging wildlife, and including more native plants. The author, Matt Rees-Warren, lives in southwest England, a country noted for artfully gardening every corner of tiny spaces.

The fact that almost all vegetables grown in the UK are non-native (changing the way wildlife and ecosystems interact with food production) can make a dividing line between those focused on encouraging biodiversity and those prioritizing food production. The author seeks to rebalance these approaches, to preserve wildlife, restore clean water and soil health.

The opening chapter, on design, suggests observing and studying our land, letting go of previously-formed plans and following nature. Observe your garden within the framework of the four elements Earth, Air, Fire and Water, using a page of questions about the prevailing conditions. There are tips on testing the structure of the soil and its ability to drain (or hold) water. If you notice an area prone to flooding, think about making a pond, a rain garden, or a bog garden. Or think about planting short trees to suck up some of the water without overshadowing other ideas for nearby. Give forethought to plants that colonize and grow rapidly. Imagine making the garden interesting and attractive (and perhaps productive) in winter as well as summer.

You can draw up your garden plans, but expect to be flexible about what happens. Work with the contours of the land, rather than plan for lots of earth-moving (unless you want a really big pond!) Note which elements of your dream will need the best light, and look at where to put those. Observe the microclimates as well as the prevailing elements of the weather.

As far as possible, design a garden that takes care of itself, providing for its needs from its natural resources. Make a cyclical design with no waste. Consider adding chickens or ducks. Make each area as rich in species as you can, for resilience and abundance of resources. The fittest will survive, even if they are not the species you expected to thrive there!

The second section, on the soil, encourages us to take care of the mycorrhizae, which extend the “reach” of plants’ roots, getting them more water and nutrients in exchange for carbohydrates for the fungi. Aeration of the soil can be a useful project for very compacted soils, but it will destroy the mycorrhizae. Reducing tillage will conserve the fungi. I like the author’s description of soil as “the basket that holds the roots of the mightiest organisms” (trees) as well as the roots of tiny seedlings.

The soil has an important role in holding carbon, and reducing tillage is one way of conserving the carbon already in the soil. When bare, soil emits much more carbon dioxide to the atmosphere, and supports fewer life-forms that might capture and store more carbon. In the natural world, the top 3 cm (1.2”) of the soil can take up to a thousand years to grow. Let’s not degrade that treasure! Building a successful compost system is a way to work in harmony with nature. Aerobic composting is what happens on the forest floor, open to air and water, heat from the sun, and animal activity. Cold aerobic composting happens if you never turn the pile: hot compost requires introduction of new air. Anaerobic composting corresponds to bog conditions, where the organic materials are deprived of air, and may have an overabundance of water. All composting is valuable. Hot aerobic composting adds the advantage of cooking weed seeds and pathogens. Anaerobic composting, where the ingredients are sealed underground, underwater or in a container, ensures that vermin have no access. There are tips on building compost bins, making leafmould and loam, bokashi compost, bokashi bins, compost teas and biochar. Vermicomposting (a good, cold-aerobic method for those with only a small space), animal manures and compost toilets (followed by hot-composting the product) are also given space. The issue for the ecological gardener, of how organic the animal manures are, including the humanure, is discussed. Medications, non-organic foods, are not the best ingredients. We work with what we have.

The third section is about plants. The native plants mentioned are, like the author, British. These plants are the European non-natives in the USA. Sometimes they are a problem. In helping you choose what to grow, consider plants that grow best in the open, in shade, in deep shade, in dry areas, in grassland, in marshes and bogs. You can substitute plants native to your region. There are tips on turning a lawn into a wildflower meadow. You need to start in the fall, cutting the grass very short and scarifying it to pull out 80% of the roots. The flower seed needs bare soil to germinate in, so roll or in some other way, press the seed firmly into the soil. Native plants generally shed seed in the fall, and some need a period of cold to break dormancy.

There are tips on scything, on planting a mixed species hedgerow (and for turning a hedge into a hedgerow of mixed species); on laying (pleaching or plashing) a hedge to keep livestock on one side of it, and on collecting seeds from wild plants. There is a table of which species need seed stratification, and which need scarification, and details on how to do each of those, and on taking and rooting cuttings.

Chapter 4 is about water, starting with rainwater “harvesting” or catchment. How we source, use and reuse water is of vital importance. Some past civilizations showed great mastery in water management: Minoans, Romans, Turks, and more. I’ve seen impressive English Victorian stonework reservoir management systems in Yorkshire and Derbyshire. One plastic rain barrel holding 150 l (40 US gallons) doesn’t go far enough to address a garden’s needs.  Your garden might need 5000 liters/1250 US gallons. Assuming barrels would refill 8 times during the year, one barrel only provides half enough.

The author avoids plastics whenever possible, and advocates for finding old wood whisky barrels. Most of the construction projects in this book use recycled lumber, typically from dismantled pallets. For rainwater collection, used metal drums and tanks are next best to wood. Aesthetics is important too. There are tips for creating a vista. There are tips on creating “Tranquil Effects” with rain chains for roof runoff, and channels, rills and gullies to move water through your landscape. Remember to make swales and ditches to catch overflow water from all the water features, to avoid erosion, slow the water down and let it soak usefully into the soil.

Matt Rees-Warren in his element

Rain gardens are easier to make than ponds. These are areas of dedicated plantings that can absorb larger amounts of water. There is a page on how to make one. There are instructions for constructing a bathtub reed bed in your garden. Grey-water use is another way to reduce the amount of fresh water you need for your garden. Water from showers, laundry, and sinks can add up to quite a lot of potentially useful water. One way to make use of grey-water is a keyhole bed with a central funnel or basket into which grey-water is poured onto compost full of micro-organisms, with a lower level of rocks and gravel.

The next chapter covers wildlife, everything from microbes to mammals. The author says: “By adding organic matter into the soil on a regular basis in the form of compost, you will do infinitely more to aid the food web than anything else.” The decomposition of organic matter sparks many life forms. Ideally, your garden will not be closed off from the rest of the world, but will have permeable boundaries. Opening your land to wild mammals will also mean the neighbor’s cat can come and go, which can cause problems for birds and small mammals. Ponds with a natural continuous water source can become part of a water-flow through your garden. Some ponds may sometimes need the addition of fresh water to prevent complete drying out. See the section on Creating a Natural Clay-Lined Pond. Find a good site, and a source of clay (try construction sites, where there is a pile of excavated clay). After digging the hole, spread a layer of cleaned, puddled clay over the inside, smoothing it with a plastering float. Sit back and wait for the pond to fill. Once plants start to grow, wildlife will soon follow. Seed the berm around the pond with fast-growing annuals to hold the soil in place, and add perennial plants later. Water-loving plants are not happy up on the relatively dry berms. Avoid plants with big roots that will destroy the integrity of the clay liner.

Pollination is important for most plants, so be sure to encourage pollinators: chiefly butterflies, moths and bees.

The chapter on materials includes growing your own plant stakes by coppicing and pollarding, as well as repurposing found and sought-out materials. Avoid new materials if possible, and when shopping, choose biodegradable materials and sustainable sources. Matt makes suggestions for repurposing many discarded items in creative ways. Plant your own coppice with a mix of whips of native trees such as willow, hazel, alder, ash and lime. After five to ten years, start harvesting rods by cutting the stems right down at the base. This kind of pruning can extend the life of the tree, which is perhaps counter-intuitive, but history and tradition bears it out. You can plan for a rotation of pruning each of the trees, some each winter. There are pictures and tips on coppicing a hazel.

We know it’s a poor worker who blames their tools. Here is information on maintaining and sharpening tools. I learned that waterstones should be soaked in water before use until no more bubbles come from the stone. I’d been in the habit of just dotting some water on the surface of the stone! Now I know better.

Mud mortars are explained as an alternative to cement. Matt also addresses the issue of agricultural plastics. He advocates for committing to a closed system, whereby you never send plastics to the landfill. Hard to do, but it does wonderfully focus the mind. And we can all do better at conserving and reusing plastic items.

The Ecological Gardener is a handbook for all who seek to be more ecological while working and playing outdoors on our land. It’s an earnest attempt to move the needle on the environmental impacts of our actions towards living more lightly. It’s not a soapbox, but a toolkit.

Why I don’t use Peat Moss

 

Walking on the Yorkshire Moors. Credit Daniel Wildey Photography/North York Moors National Park

When I was a new gardener at Twin Oaks Community in central Virginia, I was a bit surprised to find the crew using peat moss in the potting mix. I come from the UK, where gardeners’ use of peat has long been challenged as unsustainable and ecologically destructive. I lived in Yorkshire and frequently took walks up on the “tops” (moors). I admit it did take me a while to come to appreciate the treeless stark beauty there. The moors are wild, wet and windy. You get wide views (if the mist or rain is not too thick). You get space and isolation, and tons of very fresh air. There are ancient trackways where salt and coffins were carried, and standing stones, and abandoned industrial workings such as millstone carving sites and mines. If you go alone, you need good navigation skills in the less-traveled parts. If you are unwary, you can find yourself thigh-deep in a bog, and the water is never warm.

Cutting peat turfs for heating. Photo Wikimedia Commons

In previous times, various efforts were made to drain the water and make the land arable or forested. Meanwhile, local people (or at least the “hearth-holders,” and I feel sorry for the others) had Rights of Turbary, meaning that each summer they could cut out slices of peat (turfs or turves) from the section of common or private land they had rights to, dry them and haul them home as winter fuel. More recently, interest rose in preserving the unique moorland ecosystems. The rich had their pheasant shoots, and they still do. The gamekeepers conducted controlled burns of the heather and bracken to make sure the plants grew tender new shoots at the time of year the young pheasants needed them. Sheep had some access. People enjoyed the birdlife, the heather flowers, the carnivorous sundew plants, the cottongrass, the mosses and other bog plants.

Roundleaf sundew, a carnivorous plant. Photo iNaturalist

There are many types of peat moss, including 160 species of sphagnum moss. It grows slowly, and needs acidic water and cool-to-cold temperatures. It could be a renewable resource in places with very large amounts of untouched peat bogs, like Canada. That is, if we only harvest small amounts. But, oil and coal could theoretically be renewable if we wait long enough! The Canadian horticulture industry does have some guidelines and best management practices and a certification program for Responsibly Managed Peatlands. You can read about them in Jennifer Zurko’s article I describe later. There are some restoration projects, including the Moss Layer Transfer Technique, a kind of grafting or transplant process. The suppliers do have some “enlightened self-interest” in preserving their goose that lays the golden eggs. In 2021 in the UK, a phased-in ban on peat-based growing media will reach a complete ban in 2024. The rate of progress with phasing out sales was seriously set back when lots of new gardeners wanted peat during the Covid pandemic! Most retailers did not start phasing it out! The UK supply of peat is much smaller than in Canada, and the situation there is critical.

Relatively recently, many people have realized the enormous value of peat bogs as a big carbon sink. Keeping carbon in the ground is one way to strive to reduce the impact of climate change. The wet, anaerobic conditions hold the carbon in the dead plant matter. If we burn it, obviously the carbon is released. This is also true if we use peat in our gardens, mixing it with other ingredients and exposing it to the air. Peat is not coal, it’s not yet a fossil fuel, but it’s on its way. If you use peat, you may have noticed the old heather twigs, and leafy and mossy bits.

In a small country like the UK, it’s more obvious that the rate of use of peat exceeds the rate at which it is laid down. The UK is committed to limit or to completely stop peat use in the home garden market in 2024, and in the professional market by 2030. In the US, we import most of our peat moss from Canada, a large country with a relatively small population clustered close to the US border. Who sees the peat bogs? But the environmental impact is the same. Using peat moss contributes to global heating.

Screening compost for seed compost and potting compost.
Photo Wren Vile

We reduced our use of peat moss at Twin Oaks by first discovering that our homemade compost could be screened (sieved) and used alone for potting transplants and sowing seeds in flats. Our remaining use of peat was for soil blocks. Soil blocks are cubes of potting media that can stand alone and grow seedlings. No plastic pots! To work in a soil blocker, the mixture must be quite wet and sticky. We experimented to find a recipe with as much homemade compost and as little peat moss as possible.

Lettuce transplants in soil blocks.
Photo Pam Dawling

Next, we switched to replacing the peat with coir, the fibrous stuff from coconut shells. It is sold in compressed bricks that need soaking in water and crumbling before use. The material has been shredded, and is easy to use. This is a by-product of growing coconuts. No coconuts are harvested just for the coir. It seems like a freebie, a “waste” product. Maybe our purchase helps people in poorer countries to get more money for their agricultural efforts. Of course, getting the coir from the tropical coconut-growing regions does involve some shipping. It’s shelf-stable, so can come by ship, using less fuel than air transportation. However, maybe the coconut groves would benefit from the coir being returned to the soil below the coconut palms. There are no “wastes” in agriculture.

Soil Blocker (currently on sale) at Johnny’s Selected Seeds

We still use coir for soil blocks, but we reduced our use of soil blocks, and last year made none at all. Now we use Winstrip trays instead of soil blocks. These are heavy-duty plastic with many years (decades?) of use ahead. They have square cells with vertical slits in the sidewalls and a staggered arrangement allowing air to prune the roots of the seedlings, one of the values of soil blocks. With Winstrip trays, we can use 100% home-made compost, not bought-in imports at all. Filling the Winstrips is very quick, much quicker than getting a good block mix and ejecting each set of four soil blocks.

Transplanting from Winstrips is almost as easy as transplanting soil blocks. With soil blocks, you open a hole in the soil (I used to like a right-angled trowel for this job; Eliot Coleman advocates a cut-off bricklaying trowel). Drop the block in the hole and firm the soil back in place. With Winstrips, you poke the plug up through the hole in the bottom, then lift it out, and it’s just like planting a soil block.

Okra seedlings in a Winstrip tray in the greenhouse.
Photo Kathryn Simmons

Margaret Roach addressed this issue with Brian Jackson, an expert in soil-less growing media on her website A Way to Garden: Can we Replace Peat Moss? You can read the interview or listen to the podcast.

The January 2022 issue of GrowerTalks magazine has an article from an industry perspective: Is Peat Sustainable by Jennifer Zurko. There is an archived version of an earlier webinar, linked from the article, if you prefer that format.

Suppliers of other potting media are selling ground composted bark and rice hulls. The same questions remain. In the case of rice hulls, the additional question is, do we want to aid and abet the eating of hulled white rice? And another is whether the potting mix has any nutrients for the growing plants. If you can make and use your own compost, you can be confident your plants will get nutrients. Commercial potting mixes have nutrients added. Making a change will involve assessing your options and the results you get. Using a different medium will require other changes, like how much you need to water. It will involve paying more attention than you needed for doing the familiar.

So, we are back to using (very durable) plastics and no longer buy any peat moss. Probably we won’t buy coir again either, once we have used what we have in stock. This is one of those agricultural dilemmas everyone gets to find their own solution to. Peat bogs can perhaps be restored eventually, but we need to then leave them be, and leave peat in the ground, as with coal and oil.

Three Methods of Growing Sweet Potato Slips

Growing sweet potato slips in an old fridge used as a warm insulated cabinet.
Photo Kathryn Simmons

Sweet potatoes are grown from “slips,” (pieces of stem with a few leaves), grown from a mother root, not from seeds or replanted roots. We used to buy bare-root slips for transplanting, because we didn’t know how to grow our own, and had heard it wasn’t easy. We have been growing our own for many years now, and prefer the flexibility and reliability it gives us. We did make several mistakes initially, so I can warn you about what not to do. We have a system that we really like, and I have learned a few other methods that I will also tell you about, including one I helped out with the past two years, growing them in a hoophouse.

Disadvantages of buying sweet potato slips

  1. You need to specify a shipping date months ahead, then hope for good weather and no shipping delays.
  2. You might have late frosts, spring droughts, or El Niño wet springs, and climate change is only adding to the uncertainty, but slips that arrive in the mail need immediate attention.
  3. You have to get them all in the ground promptly, and do your best to keep them alive (because they arrive wilting).
  4. Some amount of drooping (transplant shock) is normal.
Cut sweet potato slips in water.
Photo Kathryn Simmons

Advantages of growing your own sweet potato slips

  1. You can delay planting if the weather is all wrong (frost, drenching rain, heatwave)
  2. You can grow them big and plant 3-5 nodes underground, giving more chance of survival if there is a late frost, or an early drought.
  3. You can plant them in stages rather than all on one day.
  4. You can grow extra and keep them on hand to replace casualties.
  5. The sturdy plants get off to a strong start – the transplants don’t wilt – a big advantage where the warm season is on the short side for a 90- to 120-day plant.
  6. You have more self-reliance and less money going out.

 How not to grow sweet potato slips

I made several mistakes learning to grow slips. You don’t have to repeat my mistakes! My first error – following directions written for much further south (in pre-internet days), was to try growing slips in mid-January in central Virginia. Dismal fight against nature! Likewise, I was puzzled by talk of using cold frames. Ours were freezing cold at that time of year.

Next, I set up a soil warming cable in a cinder-block-enclosed bed on the concrete floor of our greenhouse. This is how I discovered most soil warming cables have thermostats that switch off the heat at 70°F (21°C). I just couldn’t get the soil warm enough.

Sweet potatoes on a plate.
Photo Brittany Lewis

Three Successful Methods of Growing Sweet Potato Slips

  1. Twin Oaks slips-in-flats method
  2. Boutard single node cutting method
  3. Hoophouse or caterpillar tunnel bedding method (Twin Oaks)
Flat of home-grown sweet potato slips.
Credit Kathryn Simmons
  1. Twin Oaks Slips-in-Flats Method

I’ve written about this before, so I’ll just give you a link to open another page.

Starting Sweet Potato Slips discusses pros and cons of growing your own slips, and describes our “slips in flats” method, which I learned from Hiu Newcomb of Potomac Vegetable Farms. Here is our Worksheet we use to stay on track with that task.

Sweet Potato Plan 2022

 

Single-node sweet potato slip at 16 days.
Photo Anthony Boutard
  1. The Boutard single node cutting method

Anthony Boutard and Caroline Boutard Hunt wrote an article about single node sweet potato propagation (which they learned from John Hart of Cornell) in Growing for Market in March 2015. They farm in Oregon and New York respectively.

Both the slips-in-flats method and this one start at the same time, planting roots in damp compost in a warm greenhouse. I corresponded with Anthony Boutard about our respective methods. He pointed out that the slips-in-flats method needs a lot of warm space to grow the slips, at a time when warm space is at a premium. Our method does take us from early March to mid-May.

The single node cutting method uses only 10-20% of the number of mother roots compared to the slips-in-flats method. It uses tiny plants in plug flats, saving on greenhouse space, and only needs 18 days between cutting the slips and planting in the field. The smaller plants can experience less transplanting shock than larger plants. On the other hand, I do not think they have the resilience that multi-node plants have, for example if a late frost strikes.

When these plants grow in the field, their root production is from the single node. This can lead to fewer, but very large tubers, an advantage or a disadvantage, depending on your goals. Better in climates with a short warm season than in hot places, although digging after a shorter growing period would be possible in warm climates.

This method can be used to grow more plants from purchased cut slips, which is very helpful if you are growing a rare heirloom with limited propagation material available. Plant the bought slips in the greenhouse and grow them on until you can make cuttings.

Like the slips-in-flats method, this one buys time if the weather turns bad and you need to back pedal on your planting out date.

Single-node sweet potato slip showing roots three days after striking the cutting.
Photo Anthony Boutard.

To prepare single node cuttings, cut a slip from the mother tuber and cut off about ¼” (6mm)  above a leaf node (the swollen point where the leaf emerges). In the leaf axil is a bud which will grow a shoot, and just below the bud is a ring of cells that can grow roots. You can trim back the leaf stem, or leave the leaf on. Make the second, lower, cut just above the next node down. You can make several cuttings from one regular slip.

50-cell plug flats work well to grow the cuttings. Push the lower end of the shoot cutting at an angle into the cell, creating an even V with the leaf stem. If a cutting is too tall to fit your cell plugs, you can cut more off the lower end. The new shoot will then grow upwards easily from the bud in the leaf axil.

Keep the trays warm and moist, and plant out after only 18 days, into well-prepared damp soil, with drip tape in place. Delaying planting for 10 days or so is not a problem.

This post includes a discussion of the Single Node Method, in an article in Growing for Market magazine by Andrew Schwerin from NW Arkansas. In warm climates, only use this method if you want really big tubers!

Hoophouse beds of sweet potato mother roots in early May
Photo Pam Dawling
  1. The Hoophouse Bedding Method

I learned this method from my friend and colleague River Oneida, who grew slips for Southern Exposure Seed Exchange. He planted up 4 beds 45’ (14 m) long with three rows/bed in a single-layer hoophouse and grew an average of 4000 slips/week, for a 6 week sales season (24,000 slips), with a peak and bell-curve ends of the season. Caterpillar tunnels could also work.

Store your saved roots at room temperature. From March 1 onward: start the sweet potatoes sprouting indoors in stages, as heated space permits, at 85°F (29°C), and high humidity. Remove any rotting potatoes. When each potato grows ¼” (6 mm) sprouts, take it out of the heated space and replace with new ones. Put the ¼” (6 mm) sprouted ones at room temperature to slow them down for batching with later ones.

In March:  Cover the bed area in the hoophouse with a single layer of clear plastic, and kill any weeds that pop up. Four weeks before shipping starts (on April 1 in central Virginia), prepare the beds in the hoophouse. Dig out a flat-bottomed bed 1” (2.5 cm) deep, and set the sprouted sweet potatoes an inch (2.5 cm) apart in rows. One or two sprouts are enough. If possible, don’t bed unsprouted roots

Spread some compost, not lots. Replace the soil you dug out, on top of the sweet potatoes. Add soil from the aisles, putting 1”-3” (2.5-7.5 cm) of soil on top of the potatoes. Not more. Set out drip tape and irrigate regularly.

After bedding, stab holes in the plastic every 4” (10 cm) for respiration. Check regularly, opening the plastic on warm days once slips are visible. In mid-April or whenever you see slips emerging, remove the plastic in the daytime, but put it back for frosty nights Add more soil later to cover exposed tubers if needed. Regulate temperature if you want a faster or slower rate of production.

Fresh sweet potato slips for sale from Southern Exposure Seed Exchange.
Photo Pam Dawling

Some slips will be ready from the 3rd or 4th week of April onwards. If too many slips are ready at any point, pull and heel them in outdoors. Remember to water.

I first wrote this up for an article for Growing for Market magazine, and have included it in my updated slideshow, at the end of this post. It’s a great method for people growing lots of slips (for instance, for sale). It could also be used for smaller amounts, by occupying a corner of a hoophouse growing other crops at the same time.

More Posts on Sweet Potatoes

I have written a lot on sweet potatoes at all stages from propagating our own slips, growing them all summer, and harvesting. My posts include:

Sweet Potato Propagation and Yields

Transplanting Sweet Potatoes (biodegradable plastic; deterring deer)

Planting Sweet Potatoes, includes stages of growth, and links to many other sweet potato posts, including most listed here.

Growing High Yielding Sweet Potatoes

 Sweet potato harvests over the years (2020) summarizes my writing about harvesting, including Harvesting Sweet Potatoes (2016); Sweet Potato Harvest (2015) and again (2015) and earlier (2014) and in 2013, 2012

What Makes Sweet Potatoes Sprout (during storage)

I also have a blog post for Mother Earth News Organic Gardening blog, about growing sweet potatoes. And I have several articles in Growing for Market, which you can access online if you have a Full Subscription.

More information

For more info, see

ATTRA Sweet Potato: Organic production

North Carolina State University, Pests of Sweetpotato
North Carolina State University Diseases of Sweetpotatoes.

I have an updated Sweet Potato Slideshow  

Growing Sweet Potatoes from Start to Finish 2021

Workhorse Crops for March

 

Flats of transplants in our cold frame ready for transplanting.
Pam Dawling

We’ve just got a few months left in my monthly series of 14 Workhorse Crops (asparagus, beans, cabbage, carrots, chard, collards/kale, garlic, potatoes, sweet corn, sweet potatoes, tomatoes, watermelons, winter squash, zucchini/summer squash). These crops are reliable and productive under a range of weather conditions. You can use the search box to find other posts in the series, such as February.

Spring is on the way! Many more crops to plant this month! Our average last frost (over the past 14 years) here in central Virginia is April 29. We reach 11 hours of daylight on February 20, and we and everyone else will reach 12 hours on the March 20 Equinox. It’s all go!

In our hoophouse we are clearing bolting crops and transplanting spinach (the “Racehorse” of this series) wherever we have space along the edges of the beds. The tomatoes go in in March and squash, cucumbers, and peppers in April. Those crops will occupy the centers of the beds, before taking over the whole width. Our greenhouse is filling up with transplants.

Workhorse Crops to Plant in March

Young spring cabbage with a hay mulch. Wren VIle
Cabbage

We transplant our early cabbage around March 6. We had trouble with mice in the greenhouse in early February and lost quite a few seedlings. We also made the mistake of using seed that was too old. So we will have only one bed of early cabbage this year, not two. We did try to make up for the losses by resowing fast-maturing varieties, but we still ended up short. We like Farao (60d) and Early Jersey Wakefield (63d). Both numbers are seed to harvest. Subtract 20 days if counting from transplanting to maturity. We will cover the bed with thick rowcover for the first few weeks after transplanting.

Carrots
Newly emerged carrots with indicator beets.
Photo Kathryn Simmons

We sow carrots in mid-March, and again at the end of March. The mid-March sowing takes from 9-19 days to germinate, depending in on the soil temperature. The end of March sowing takes 9-12 days. We sow a few Indicator Beets at the beginning of the bed. Beets germinate one day sooner than carrots at almost any temperature. When we see the red loops of the beet stems emerging, we know it’s the day to flame weed the carrots.

Chard

We sow chard (and leaf beet, the type of chard closest to spinach) on March 24, but you can start earlier if you want earlier harvests. Chard seed will germinate from 41°F (5°C) to 95°F (35°C), and the best temperature is 86°F (30°C), when it needs only 4 days. Our goal is to use chard as our main summer leafy green after the kale, collards, broccoli and Asian greens have all bolted. In spring we usually have lots of cabbage, broccoli, collards and kale. Maybe we should do some earlier chard this year to make up for lack of broccoli and troubles with cabbage and over wintered kale?

Collards and kale
Young collard plant (Morris Heading, I think) Pam Dawling

In mid-March we will be transplanting Vates kale and Champion or Georgia Green collards directly from the soil in our hoophouse out into the garden. We usually grow Morris Heading collards but this year we are trying something different. We’ll use rowcover for the first few weeks. I have written before about bare-root transplants. This method saves us a lot of time, and saves greenhouse space. See Workhorse Crops in February for details about sowing these crops in the hoophouse.

Potatoes

Another mid-March task for us is potato planting. I wrote a whole series about every stage of potato growing last year. So I won’t say more here.

Hoophouse beans
Tomatoes, green beans and cucumbers in June.
Photo Alexis Yamashita

We don’t grow green bush beans in our hoophouse every year, but this year we will. As with other late winter/early spring hoophouse crops, we sow beans in our hoophouse a month earlier than we can sow outside. We aim to sow in the hoophouse on March 20. Of course, if it is particularly cold then, we will wait. We’ve found that beans sprawl more in our hoophouse, so we buy an upright fast-maturing variety, such as Strike.  We’ve also found that the edge beds are too cold for beans in late March, so if the crop rotation would have us use an edge bed, we sow beets or some other crop instead. We will use thick rowcover on nights that are forecast to be frosty outdoors. See mention of hoophouse beans in January.

Hoophouse tomatoes
March hoophouse bed prepared for tomato transplants – holes dug, compost added.
Photo Wren Vile

Mid-March is our target transplanting time for tomatoes in the hoophouse. We grow two beds, one of earlies (less than 71 days) and one bed of reliable favorites (Tropic, Jubilee) along with two plants each of other varieties we like or are trying out. Each 96ft (29 m) bed has two cherry or grape tomato varieties, with two plants of each. We plant the shortest varieties at the east end and the tallest (the cherries) at the west end, so that all the plants get the best possible light. (Our hoophouse has the long walls on the south and north.) We update our Tomato Rampancy Rating list each year.

This year in the early bed, we are growing Five Star Grape 62d, Sun Gold 57d, Garden Peach 71d, Mountain Magic 66d, Stupice 62d and Glacier 56d. Mountain Magic is a new favorite (it doesn’t suffer from green/yellow shoulders) and we have increased the number of those plants, reducing numbers of Stupice and Glacier.

Hoophouse tomatoes with yellow shoulders. Glacier or Stupice.
Photo Pam Dawling

In the other bed we are growing Cherry Bomb 64d, Black Cherry 64-75d, Geronimo78d, Striped German 78d, Amy’s Sugar Gem 75d, Green Zebra 72-86d, Cherokee Purple 72-85d, Tropic 80d, Jubilee 80d, Estiva 70d, Pink Boar 75d, and Mountain Fresh Plus 75d.

We use the Florida string-weaving (or basket-weaving) technique to support our plants. More about that task in future.

Indoor sowings for later transplanting outside or in the hoophouse

In March we will sow our hoophouse cucumbers and squash, and our outdoor peppers, eggplant, maincrop tomatoes, and our first outdoor zucchini and summer squash. And some non-workhorse crops. Also, we start our sweet potato slips. I covered growing sweet potato slips in another post. On March 24 we start our chard, as already mentioned.

Workhorse Crops to Harvest in March

Collards and Kale can be harvested outdoors here in March, from overwintered plants. This past fall, we were late getting our kale established and the combination of a mild December and a cold January has damaged them badly. We had 3 nights in January down to 10°F (-12°C). Normally we can harvest those beds once a week each in March. 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.

Overwintered Carrots and Cabbage are a possibility some years, but not this one!

Garlic scallions prepared for sale. Typepad.com

Garlic scallions are ready to harvest here from mid-March. These baby garlic plants offer a welcome change form leafy greens and root vegetables. We start to dig the plants once the leaves have reached 7” (18 cm). Wash and trim, cook and enjoy! Yes, you can eat them raw if you like! Some years we have made a big planting, and it has provided for us into May (when they are starting to bulb).

Hoophouse Workhorse Harvests in March

Our Red and White Russian kales are now producing well. These are Siberian-type kales, that keep growing (a bit!) in cold weather. We harvest the outer leaves and stand them on end in a bucket in a little water. The wilt very easily, so we try to keep them in the shade and get them to the cooler promptly.

White Russian kale ready for harvest in our hoophouse. Photo Pam Dawling

Bulls blood beet greens, chard, and some greens not in our Workhorse group, (turnip greens, and spinach) are still going strong. Our experimental carrots are still doing OK, although I’m not a fan of giving them hoophouse space for such a long time with no harvests. I think we would have done better to harvest them in December. The foliage is getting bedraggled, and I fear the roots are getting woody and less sweet. This is all an experiment by one of the others on the crew, who will be studying the results.

Workhorse Crops from Storage in March

In March we can eat carrots, garlic, potatoes, sweet potatoes, winter squash and cabbage from storage, while they last. We do still have potatoes, sweet potatoes and butternut squash. Also we have frozen summer goodies, and pickled things, sauerkraut, pickled beans, and canned goods like salsa.

Garlic beds next to rowcovered broccoli beds, under a stormy sky.
Photo Wren Vile

Workhorse Crops Special Topics for March: DIY Weather Forecasting

Learn your local weather patterns by keeping records of daily max and min temperatures and rainfall, and watching what happens.

Our mid-Atlantic climate is controlled by three weather systems, mainly by moisture from the Gulf of Mexico, the Bermuda High Pressure area in summer, and recurrent waves of cold Canadian air in winter.

Rain (statistically fairly evenly distributed throughout the year in our county) has slight peaks in January, February and March and again in early June and August.

Some parts of our area can experience long periods of drought: September-November is the drier season but it’s also the hurricane season, so the net result is very variable.

We use Wunderground forecasts, but subtract 5F° (2.5C°) from their forecast night lows for our nearest town, and mentally downgrade the chance of rain by 10%, as rain often passes us by as it scoots along the river valley north of us. 3/30 pm in winter is a good time to look at the night forecast.

WeatherSpark is a great resource. You can enter your zipcode or town and discover a large range of charts and graphs about weather in your area. It will help you learn what to expect.

Immature frosty cabbage. Photo Lori Katz

As for predicting frost, here are some of the factors to consider, that make frost more likely here:

  • If the date is after 10/14 or before 4/30 (ie within the average range for frosts here)
  • If the Wunderground forecast low for Louisa Northside is 37°F (3°C) or less.
  • If the daytime high temperature was less than 70°F (21°C).
  • If the temperature at sunset is less than 50°F (10°C).
  • If the sky is clear.
  • If the soil is dry and cool.
  • If the moon is full or new.
  • If there is little or no breeze, although if temperatures are falling fast, the wind is from NW and the sky is clear, then polar air may be moving in, and we’ll get a hard freeze.
  • If the dew point forecast is low, close to freezing, a frost is more likely. Frost is unlikely if the dew point is 43°F (6°C) or more.

More on Insectary Flowers; Vegetable Crop Resources, Especially Weeds

 

Borage flowers attract many beneficial insects. Spot the honeybee! Photo Raddysh Acorn

More on Insectary Flowers (to attract beneficial insects)

A reader responded to my post Growing flowers to attract aphid predators in early spring

“Isn’t too cold for the predators to be around, Pam? unless they hibernated in the greenhouse. but even so, it’s still cold in there at night. We have some aphids too in the tatsoi and some of the lettuce, so thank you for all the tips, and the life cycle. I had not quite realized that the cycle was so short. I grow borage in the hoophouse but in the ground – the plants get large and gorgeous with clouds of blue flowers in March and April – much bigger and healthier than anything I try to grow outside. The honeybees absolutely love it and they attract are a lot of other insects too.”

Yes, it has been still too cold for predatory insects to be around, until this week, when ladybugs greet us around every corner. Our idea with the flowering plants was that by starting the plants in the fall, we’d have actual flowers earlier than if we started in “spring”, and that perhaps the extra stresses would even cause the plants to flower earlier. Apart from the borage, none of the others have flowered yet (Feb 23). We likely need to fine tune our sowing dates. We sowed at the very beginning of September and the very end of October. That two-month gap probably has better sowing dates! We noticed that some of our plants were not very cold-hardy. Some died and some had to be pruned of dead bits. Since then, we started more flowers in our greenhouse on February 1. Another thing we’re noticing since early February is that the plants in pots dry out very fast. It’s probably better to get the flowers in the ground in the hoophouse and greenhouse as soon as they are big enough, as suggested by the results of my reader quoted above, with borage.We had thought that having them in pots would enable us to move them into trouble spots.

Vegetable Crop Resources, Especially Weeds

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

A newly released handbook from Sustainable Agriculture Research and Education (SARE), Manage Weeds On Your Farm: A Guide to Ecological Strategies by Charles L. Mohler, John R. Teasdale and Antonio DiTommaso, is set to help us all. I haven’t read it yet (although I am looking forward to that!), so this is not a review, But these are three big names in weed science, and SARE is well-known for providing solid information on sustainable farming.

Silver Queen sweet corn with a wilting pulled amaranth plant in the center
Photo Kathryn Simmons

I had the great good fortune to attend a workshop by Chuck Mohler years ago, and got some realizations that forever changed my approach to weeds. Top of the list is that some weeds, such as pigweed (amaranth species), don’t distribute any seeds until they have grown very big. Until that point they are not threatening next year’s farming efforts. We used to get huge pigweed plants in our sweet corn, and fatalistically did nothing once we were in there harvesting, somehow believing it was “too late”. No, it’s not! They hadn’t seeded. We started to make a practice of pulling the huge pigweed every two days while harvesting corn. Often it was necessary to stand on the base of the corn plant to hold it in place, while pulling the weed. Then all we had to do was drop the pigweed between the rows. Sweet corn ripens in hot weather and the weeds soon died, rather than re-rooting. All those big leaves sucked the moisture right out of the plants. Be extra careful if you have spiny amaranth. We have twice eliminated this weed form our gardens, by diligent hand-pulling, only to have it reappear a few years later!

Galinsoga – a fast growing, fast-seeding weed of cultivated soil.
Photo Wren Vile

Conversely, galinsoga forms seeds very soon after germinating, while still small. This weed is one to strike early and repeatedly. It readily re-roots in damp soil. Our strategy when we are too late to hoe and have to hand-pull them, is to shake off as much soil as possible, then to either twist and break the stem (if there are not many), or “shingle” the weeds, laying them down with the roots of one on top of the leaves of the previously pulled plant, providing a surface of roots all exposed to the air, and none touching the soil. This works quite well. Timely hoeing is much better, of course!

Manage Weeds has chapters on How to Think About Weeds, Cultural Weed Management, Mechanical and Other Physical Weed Management Methods, Profiles of successful managers,  and then the alphabetical rogues gallery of grass weeds and broadleaf weeds.

This book and all the online information from SARE is free of charge. You can buy print copies if that suits you better. Other good resources from SARE, while you’re at their website, include several other books:

Building Soils for Better Crops

Managing Cover Crops Profitably For many of us, this is the “Cover Crops Bible”

Systems Research for Agriculture

Crop Rotation on Organic Farms 

There are also podcasts, bulletins, videos, Topic Rooms and interactive pages to explore.

Winter Vegetable Production Methods

For those who missed the Pasa Sustainable Agriculture conference, here is my slideshow Winter Vegetable Production Methods, From the Field to the Hoophouse

Winter Vegetable Production Methods, From the Field to the Hoophouse Dawling 60 mins 2022 2.11 9am

Some Highlights of the PASA Conference

I enjoyed attending the in-person conference of Pasa Sustainable Agriculture. This is the first conference I’ve been to in person in two whole years. PASA did a lot to ensure the conference was as Covid-safe as possible. They limited the number of attendees (there were still plenty to ensure lots of chances to exchange information). Everyone had to test on their day of travel to the conference, and speakers had to test every day of speaking. For me that was all three days. Everyone was masked, nearly all with KN95 “real” masks. The hotel housekeeping staff only came in after we left. (We could have requested the service, but, heck, I can make my own bed!) In the workshop rooms, the chairs were spaced 6 ft apart. The trade show had wide aisles, and meals could be taken out of the dining room to a quiet spot. Just getting to be there was a big highlight for me! I left feeling energized and enthused, and very grateful to the PASA team for preparing such a successful event.

There were four sessions of workshops each day, with one-hour breaks between, allowing time to visit uncrowded trade booths, catch up with old friends, and make new ones. We were well-supplied with snacks and beverages during the breaks. There were socials with more snacks at the end of the day.

I did have trouble with the conference app, but then, my phone is limited in what it can do. Likewise I failed to upload my slideshows to the platform, so I ran them off my flashdrive. My pdf handouts did make it onto the app, so if you wanted one of my handouts, you can find it there and here:

Young Yukina Savoy plants.
Photo Ethan Hirsh
Optimize your Asian Greens Production Dawling PASA handout 2022 2.10 9am
Young spinach seedlings.
Photo Pam Dawling
Winter Vegetable Production Methods From the Field to the Hoophouse Dawling 2022 2.11 9am 6 page handout
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
Growing Sweet Potatoes from Start to Finish Dawling 4 pg handout 2022 2.12 11am.docx

Each of the ten workshop sessions had a choice of eight or nine workshops. I had thought I might hunker down in my hotel room when I wasn’t speaking, to minimize my chance of catching Covid, but as permaculture author Darrell Frey said “This feels safer than going to the grocery store!”

I enjoyed several workshops presented by others, including:

On-Farm Experience with Organic No-Till

Sam Malriat from Rodale

No-Till sequesters carbon in the soil, but simply never tilling does not improve the soil. Chemical no-till uses lots of herbicide. Don’t be obsessive about no-till. Shallow tillage can be a responsible choice, as incorporation of organic matter is valuable. Adding cover crops, compost or manure, grazing, and a good crop rotation, can increase the OM, and thus increase the soil water capacity enormously.

Crimson clover cover crop
Photo by Bridget Aleshire

To overcome the challenges of no-till, you need a very good cover crop stand that will provide a thick mulch when terminated; a competitive cash crop; a way to plant into the residue, and a back-up plan in case one of the requirements doesn’t pan out.

Sowing corn into rolled and crimped hairy vetch does not work well, because corn is a heavy feeder and not very competitive. Better is to undersow the corn at V5 or V6 (stages of vegetative growth) with white clover or crimson clover in September. It’s important to get good seed to soil contact. The clover grows when the corn dies. This is in Rodale Country in PA. If the clover can be left growing until the second year, cabbage can be transplanted into it. His slides showed the success of this system after an unpromising start.

Pumpkins can be direct seeded in crimped and rolled (or mowed) winter rye. There is a lot of difference in thickness of the mulch between rye sown in August and October.

Organic Solutions: Pest Management

Drew Smith and Emily Gantz from Rodale

There was a big drop in pesticide use in the mid 1990’s as GMO crops came in. But then a big uptick as resistance to the GMO crops developed. Currently, almost all non-Organic seeds contain neo-nicotinoids, even though they provide no economic benefits.

Crop rotation is the single most important thing you can do to manage pests. Drew showed us the IPM triangle, and we worked our way up. To succeed in preventing pest infestations, planning of all aspects of growing the crop is vital. As is regular scouting of each crop. Cultural controls include the physical aspects of the planting. Other physical controls include mechanical aspects of growing the crop. Biological controls include encourage beneficials, releasing biological agents. Greater biodiversity provides greater stability. See Cornell Entomology https://biocontrol.entomolgy.cornell.edu/index.php

Native Pollinators: Identification, Habitat Needs and Resources

Sarah Koenig and Ryan Stauffer from the Audubon Society

A bee pollinating squash.
Photo Pam Dawling

There are 4000 species of bees in the US (20,000 globally). 70% of food crop species rely on honeybee pollination to some extent. Native bees mostly nest in the ground. Don’t kill them by compaction (or weedkillers!). Use native flowers to attract native pollinators.

Using Tarps to Reduce Tillage on Small Vegetable Farms

Ryan Maher, Cornell Small Farms & Bob Tuori, Nook and Cranny Farm

More growers are trying tarping for weed control, killing cover crops, maintaining a good soil temperature, avoiding crusting and compaction, keeping beds dry enough for planting and reducing dependence on single-use plastics. Challenges include the heavy weight, the aggravation of using sand bags, especially in windy places, ponding of rainwater runoff, and the frustration of providing perfect vole habitat.

After 28 days in summer, you gain 200 GDDs. Plant-available soil N increases by 2 or 3 times from the plant residues. How soon does it dissipate after removing the tarp? Tarping for 3 weeks after shallow tilling kills the living weeds, improves crop establishment and reduces weed emergence by up to 83%. Think of tarps as a tillage tool! Do plan for weed management after removing the tarp. Pigweed and amaranth can become worse!

We haven’t tried tarps yet. Early September photo of hay mulched June-planted potatoes.
Photo Kathryn Simmons

Bob Tuori spoke about a SARE trial of tarping in the Northeast. He compared potatoes grown with and without prior tarping, both patches with and without hay mulch after planting. The tarped area needed sandbags every 10-15 ft. The tarp was removed June 4, weeds were counted June 24, then the patches were mulched. (I hope I got that right). I did not write down all the results, but the only-mulch area grew 17.4 lbs per hour of work, and the tarp-only area grew 13 lbs per hour of work. See the SARE report for the details.

Harvesting Techniques for Small- to Mid-Scale Vegetable Farms

Julie Henninger of Good Keeper Farm and Matthew Lowe

We saw good tool and equipment storage, and learned the benefits of growing head lettuce on landscape fabric (no rotten bottom leaves, no weeds). Muir is their favorite lettuce for spring, summer and fall. At $3/head, a 95ft row planted at 9” spacing earns them $1300, if they have a 15% loss.

Beautiful baby lettuce mix in our hoophouse.
Photo Wren Vile

We learned the importance of sharp knives or scissors for cutting baby greens with minimal cell damage and browning. Theirs sells at $12/pound. They grow Salanova, which brings in $1140/bed at each cutting. If they cut whole heads, these bring in $1476 per bed.

For loose carrots, they sow rows in pairs 2” apart, with 6 rows on a 30” bed, using a stale seed bed and flaming. They sell 1000 lbs per week. Julie Henninger emphasized not wasting time by setting the carrots down in piles. Minimize the number of times each crop is touched. They have modified a cement mixer to wash 25-45 lbs at a time.

Training and communication are also very important. New workers must master the task first, before chatting. Minimize distractions. Send crews out with a strong role model each, to keep the crew working at a sustainable pace. If working with a crew with diverse abilities (eg children), provide a clear short task with a beginning and an end, to give a good sense of achievement.

I also attended the Plenary, Why Is Farming So Hard & What Can We Do About It?  on Friday with Brennan Washington, Sarah Mock and Dr Jessica Gordon Nembhard, who were livestreamed and recorded.

I participated in the book swap, setting out some spare handouts I had in exchange for a couple of magazines. I enjoyed the Farm Innovations poster display of tools and techniques to improve production or save resources (or both). I liked that previous years’ posters were available as pages in several ring binders.

In the Trade Show there were 60-odd vendors. I checked in with Nifty Hoops, a company who will deliver a hoophouse and put it up for you in one day, or help you put it up, teaching as you build. We put ours up ourselves, in 2003, and we were inexperienced and slow, and had to work on it in the (hot) afternoons, after spending the mornings farming. At events when I talk about hoophouse growing, I’ve sometimes been asked if there are companies who will erect hoophouses (high tunnels), so it’s good to be able to pass on this contact. Nifty Hoops also sell interesting components such as DC-powered inflation blowers. (734) 845-0079.  They have videos on their Facebook page

I picked up some publications from ATTRA, who have supplied me with great vegetable growing info since before the internet. (We used to call them up and ask for publications to be sent in the mail).

The Mini-Treffler manual harrow

I also was fascinated by the Mini-Treffler, from OrganicMachinery.net, a manual rolling tine harrow for crops in beds.

  • The TINY Treffler is a hand drawn harrow with the working width of 80cm (2 ft 7 in), 100 (3 ft 4 in) and 130cm (4 ft 3 in)
  • Shares the same principle with the big Treffler harrows: in the row harrowing, adjustable tension and the patented tine suspension
  • Each tine follows the contour of the field and the downward pressure remains constant
  • The TINY is effective throughout the growing season in greenhouses or for small enterprises in vegetable production or seed propagation
  • Wheels extendable from one or both sides to straddle a bed

I gathered literature for our garden crew as well as our dairy, orchard and poultry people, and an assortment of free pens, notebooks, stickers.

PASA also had a virtual conference, spread out over a couple of weeks in January. I’m sure there was great information there too, but our rural internet is not up to the task of virtual conferencing, so I’m in the dark. Pasa intends to keep a virtual conference next year as part of the mix – it works better for farmers who cannot easily leave the farm, it reduces the carbon footprint of travel, and saves on travel and hotel or BnB costs. Maybe next year I’ll have better internet. Maybe Covid will have receded. This year’s conference was great! I look forward to next year’s!

 

Growing flowers to attract aphid predators in early spring

Borage flowering in our hoophouse in January, among the lettuces. Photo Pam Dawling

Last July, when sheltering indoors from the heat, planning next winter and spring’s hoophouse crops, I researched and wrote up Controlling Aphids in Early Spring

I also have a post (another July information-gathering project!) about Insectary Flowers to Attract Beneficial Insects outdoors and in, at various times of year. At the end of April we sow several plug flats of different flowers to plant out in Insectary Circles at the ends of our outdoor raised beds. We hope to find a similar approach that will work earlier in the year for hoophouse and greenhouse aphids.

Ladybugs of Maine
Poster from the Lost Ladybug Project

Aphid predatory insects such as ladybugs, lacewings, aphid  parasites, damsel bugs, braconid wasps, rove beetles, syrphid flies, and spined soldier beetles are attracted to plants with small flat open flowers, like alyssum, dill, yarrow, buckwheat, sunflowers, and cosmos. This is a rather loose and general statement. On a big scale this is known as Farmscaping, and you can read about it in a publication from ATTRA; Farmscaping to Enhance Biological Control . You can use this publication to make a specific plan to tackle particular pests. Ladybugs are a good general help because they eat the eggs of many different pest species. Organic Integrated Pest Management from ATTRA gives wider information about managing pests organically.

 

Ladybugs of South Dakota
Lost Ladybug Project

eOrganic has many articles on Insect Management in Organic Farming Systems, that explain ways to tackle pest problems with ecologically-based practices, starting with actions chosen to reduce the chances of the pest ever getting a grip on your crops.

Aphids can get out of control in early spring in our greenhouse and hoophouse, as they become active before their native predators, such as ladybugs, emerge from hibernation. We have a particular problem in our hoophouse and in our greenhouse on the eggplant, pepper and tomato transplants from mid-April to mid- to late-May depending when we manage to get them under control. We are implementing our plan that we made in the summer.

Insectary flowers against aphids

Meanwhile in January we got bad aphids on the lettuce and, of our flowers to attract beneficials, borage was the only one flowering. It was not enough. We did three sprays of soapy water at 5 day intervals to kill the aphids.

Pepper plant with aphids. Photo Pam Dawling

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

This week, I want to give a progress report on the flowers we are growing. The chart gives details of the ones we chose, where we found the seed, and which months we decided to plant them in.

September-sown Borage flowering in our hoophouse in January. Photo Pam Dawling

The first planting, in September, was of borage and shungiku (Chrysanthemum greens) only. We hoped these would give us early flowers to start the program. Those plants became big enough to transplant in the ground and in 8” (20 cm) pots. We thought having some in large pots would enable us to move them to the trouble spots.

September-sown shungiku (chrysanthemum greens) in January.
Photo Pam Dawling

What I have noticed is that plants in pots dry out very quickly in both the hoophouse and greenhouse! The shungiku have looked close to flowering several times, and the accidentally dry conditions should have helped them to panic and bloom, but they haven’t. The borage flowered with pompom-like clusters, much more compact than spring outdoor borage does.

October-sown Meadowfoam plants in our hoophouse in January. Photo Pam Dawling

The second planting, in late October, consisted of Meadowfoam, Tidy Tips, Phacelia and Yarrow. Those plants are still small, as I write this at the beginning of February.

October-sown Phacelia in January. Photo Pam Dawling

They have been potted up from cells to 4” (10 cm) pots, and some are ready for bigger pots. No flowers, no help against January lettuce aphids.

October-sown Tidy Tips(and more phacelia) in our hoophouse in January.
Photo Pam Dawling

The third sowing has just happened, on February 1, and includes borage, shungiku, Meadowfoam, Phacelia, Tidy Tips and yarrow. I forgot to sow alyssum, so that will be a little later.

Slow-growing October-sown yarrow plants in January, using space in the path between lettuce beds. Photo Pam Dawling

The September-sown borage and shungiku both had some troubles with cold temperatures during January. We had a mild December, then a January with three non-consecutive nights at 10F (-12C). In our double-poly hoophouse, we roll out rowcover at night if it threatens to be 8F (-13C) or lower outdoors. That was about 6 times so far, but 10F (-12C) has been our coldest. Some of each of the borage and shungiku got cold-damaged, and some got rowcover-damaged (hasty pulling!)

So far, no beneficials have been seen on the borage flowers, and no aphids have been killed as a result. We’re still hopeful, especially about reducing aphid numbers on the peppers. More progress reports to come!

Flowers Against Aphids! Photo Pam Dawling