Austrian winter peas cover crop – Sustainable Market Farming

Cover Crops for November: Winter Rye and Austrian Winter Peas

Cover Crops for November: Winter Rye (with Austrian Winter Peas early in November)

Winter rye headed up. Mow or turn it under very soon! Don’t let it shed seed.
Photo Pam Dawling

The first half of November is the last chance to sow winter cover crops in central Virginia

Our average first frost is October 14-20. If yours is later, see my post Cover Crops for October. It is still worthwhile to sow a few cover crops up to three weeks past your average first frost, and I’ll tell you about those, with ideas on what to do if your climate is past that point.

If the area is ready for cover crops up to 10 days past the frost date, sow winter wheat or winter rye and hairy vetch or Austrian winter peas.

See Planning Winter Cover Crops, a post that includes my Short Simple Guide to Winter Cover Crops and my slideshow Cover Crops for Vegetable Growers.

Last Chance Cover Crops in November: Rye

Rye grows impressive roots that improve the soil. Kauffman Seeds

Winter rye can still be sown in the mid-Atlantic in the first half of November. Winter rye is the cereal grain rye, not ryegrass. Ryegrass comes in annual and perennial forms, but neither is a good winter cover crop here. They don’t produce as much biomass as cereal rye, and can become weeds in our climate.

Winter rye is hardier than any other cover crop and can take later planting dates. Some people do sow winter wheat in early November rather than winter rye, so if you don’t have rye seed, use wheat. It can be tricky to have the cover crop seed you want, without risking buying more than you need. Sometimes it pays to use what you already have, as it may not give good germination if saved over to next fall.

Winter rye has an allelopathic effect (inhibition of germination) on small seeds, that lasts three weeks or more after rye is turned under. This means you will need to be fairly confident that the weather will allow you to till the rye in with three weeks to go before sowing carrots, spinach or other spring crops with small seeds. Transplants are not affected in the same way. If necessary, reconfigure your crop rotation plan over the winter. Plan for the next food crops after winter rye to be ones planted after late April, such as late corn plantings, winter squash, transplanted watermelon, sweet potatoes, tomatoes, peppers, June-planted potatoes, fall brassicas, and second plantings of summer squash, cucumbers, beans.

A field of winter rye with a strip of crimson clover in early May.
Photo Bridget Aleshire

Other key features of winter rye cover crop

Rye grows 5′-7′ (1.5-2.1 m) tall.
Mow-kills at flowering, but not earlier.
Suppresses weeds (especially lambsquarters, redroot pigweed, ragweed).
Adds lots of organic matter if grown to full size.
Improves the soil’s ability to absorb and store water.
The roots hold the soil together and greatly reduce erosion.
Can be used to scavenge nutrients left over from a previous legume crop or to hold onto nutrients applied for a crop that failed.
Sow from 14 days before to 28 days after first fall frost.
Don’t sow before September in zone 7 – it may set seed.
Rye makes little growth in mid-winter, but very good growth once spring arrives.
Rye can be sown in the spring, although when incorporated, oats break down quicker.
Can be undersown in sweet corn or in fall brassicas in early September, and left as a winter cover crop.

Cover crop of rye and winter peas with flowering crimson clover. Photo Bridget Aleshire.

Include Austrian Winter Peas if possible in the first week of November

See my September post for more about the benefits of including legumes with winter cover crops grasses. Also how to inoculate legume seeds with the nitrogen-fixing bacteria. Austrian winter peas can be sown later than other legumes. See my October post for more about those. See Working with the time you have left for options if you are in another climate zone.

A key to success with legumes is to sow early enough in fall to establish before winter halts growth, and to plan not to need that plot next year until flowering time for that legume. Austrian winter peas bloom here at the end of April (about a week later than crimson clover, and a week earlier than hairy vetch). (If you have a legume that doesn’t reach flowering, you get less nitrogen for your money, and will need to add some compost or other source for the following food crop.) Suitable crops for following Austrian winter peas are ones planted after May 1: winter squash, melons, sweet potatoes, tomatoes, peppers, middle sowings of sweet corn, June-planted potatoes. This is pretty much the same list as crops that can be planted after winter rye.

Austrian winter peas
Photo https://www.uaex.edu

October 15 (our average frost date) is our clover/peas watershed (legume-shed?). Before that date we use crimson clover; after it (until 11/8, 3 weeks after our average frost date) we sow Austrian Winter Peas, along with winter rye or winter wheat.

Austrian winter peas winter-kill in zone 6, but are hardy in zone 7. Hardy to 0°F (-18°C). Sow Austrian winter peas at least 35 days before first hard freeze (25°F/-4°C) – in zone 7, that’s a 50% chance on 11/8. See Weatherspark.com for info on your location, or Dave’s Garden.

Last Chance cover crop

In the second week of November, we sow winter rye alone as our last chance cover crop. It is too late for any legumes.

Grain seed will store OK for the next year, but peas and beans really lose viability fast. If you still have Austrian winter pea seed from last year, I’d say throw it in this November rather than keep it for a third year, even if you are past the usual date. Germination rate goes down to 50% after a couple of years, and the plants won’t be sturdy.

Barbara Pleasant tells us two other ways cover crops can improve soil: Rhizodeposition and bio-drilling.

Rhizodeposition is a process whereby plants release sugars and other substances through their roots. The root tips host colonies of helpful microorganisms that go deeper as the roots grow deeper. For rye, this depth can reach 6 feet (2 m)!

Bio-drilling is what happens when cover crop roots “drill” into compacted subsoil. Oilseed and daikon radishes are cover crops famous for this action. The roots push deep into tight subsoil. Bio-drilling also happens when deeply rooted cover crops penetrate the subsoil and then die. With winter rye this can happen when the headed-up rye is mowed close to the ground in spring, or the rye is tilled into the top soil, severing the roots below till level. The next crop can follow the root channels made by the cover crop. This gives access to nutrients (including dead roots and microbes) left behind by the cover crop.

How to protect the soil over the winter if it is too late for cover crops

Carrot harvest cart. Our Danvers carrots have plenty of sturdy leaves to protect the soil over winter. Photo Mari Korsbrekke

Sowing cover crops too late means you don’t get enough growth in the fall, and the soil is not adequately protected from erosion or from weed growth over the winter. Try really hard not to leave bare soil over the winter.

If it’s too late to sow cover crops, but you do have a healthy growth of weeds, mow them at the beginning of November and then leave everything alone until early spring. The weed roots will hold the soil together and the above-ground growth will protect the soil from heavy rain. Having live plants will provide food for the microbial life in the soil.

If you don’t have weeds, but only almost bare soil, and it’s too late to sow cover crops, find some kind of organic mulch to cover the soil. When we harvest our storage carrots in November, we return the cut tops to the soil surface. Another seasonal option is tree leaves (sometimes conveniently left in bags by the curb). Best to ask the “owners” before lifting them. Other ideas include straw or hay. Woodchips or sawdust will work for winter protection, but don’t till them in when spring arrives. Rake them off and compost them nearby. If turned under, they use up a lot of nitrogen decomposing, and your crops will be starved.

More resources on cover crops

My book Sustainable Market Farming has a chapter on cover crops and many pages of charts about particular options.

Cover of Managing Cover Crops Profitably book from SARE

The book Managing Cover Crops Profitably (third edition) from the Sustainable Agriculture Research & Education Program (SARE), is the best book I know on the subject. You buy the book for $19 or download it as a free PDF from SARE.

Cover Crops for October: Winter Wheat and Austrian Winter Peas

Focus Cover Crops for October: Winter Wheat and Austrian Winter Peas

In August I wrote about cover crops such as millets, southern peas, buckwheat which are frost-killed. For most of us in the mid-Atlantic, it’s too late for those.

October is too late to sow winter-killed cover crops in central Virginia

Our average first frost is October 14-20. If yours is later, and you still have 40-60 days to your average first frost, you can still sow oats to winter-kill. If possible add a legume (soy and spring peas are easy, and will be killed by the frost, so they won’t complicate food crops next year). For us, the cut-off date for oats is September 15 if we really push it. Sowing too late means you don’t get enough growth in the fall, and the soil is not adequately protected from erosion or from weed growth.

Oats winterkill completely at 6°F (-17°C) or three nights at 20°F (-7°C. Fall-sown barley (Hordeum vulgare), grows even faster than oats, and dies at 17°F (-8°C).

There are still three weeks here when it is worthwhile to sow cover crops (up to a month past first frost), and I’m going to write about those here.

See Planning Winter Cover Crops, a post that includes my Short Simple Guide to Winter Cover Crops and my slideshow Cover Crops for Vegetable Growers. Oats, barley, wheat and rye sown too early can head up and seed before you get to winter, making them less useful, and more of a weed problem. Once we’ve reached mid-October, this is no longer an issue here.

Winter rye cover crop headed up in early May.
Photo Pam Dawling

Winter-hardy grass cover crops to sow in October

Winter rye and winter wheat can be sown in the mid-Atlantic in October. Wheat has less of an allelopathic effect on small seeds, the inhibition of germination that lasts three weeks after rye is turned under. Wheat doesn’t produce as much biomass as rye, so there’s the tradeoff. We sow wheat if the area is ready for cover crops 20-40 days before frost, allowing us to make faster use of those plots in the spring, compared to plots sown to rye.

Winter wheat prevents erosion, suppresses weeds, scavenges excess nutrients, adds organic matter, encourages helpful soil microorganisms, and the fine root system improves the tilth. It is less likely than barley or rye to become a weed; easier to kill than barley or rye; cheaper than rye; easier to manage in spring than rye (less bulk, slower to go to seed); tolerates poorly drained, heavier soils better than barley or oats.

The challenges of wheat are that it does not have good tolerance of flooding, and is a little more susceptible than rye or oats to insects and disease.

For us wheat is a good, trouble-free winter cover crop. The later it gets towards our cover crop cutoff date of November 15, the more likely we are to choose rye. Also, of course, if we have already used all our wheat seed! Winter rye is hardier than any other cover crop and can take later planting dates. More about Last Chance Cover Crop next month. Then I will also write about how to protect the soil over the winter if it is bare.

Austrian Winter Peas graphic

Secondary cover crops in October: Include legumes where possible

See my September post for more about the benefits of including legumes with winter cover crops grasses. Also how to inoculate legume seeds with the nitrogen-fixing bacteria. See Working with the time you have left for options if you are in another climate zone.

Another key to success with fall sown legumes is to sow early enough to establish before winter halts growth, and to plan not to need that plot next year until flowering time for that legume. If you have a legume that doesn’t reach flowering, it’s not the end of the world, you just get less nitrogen for your money, and won’t be able to supply all the N needs of the following food crop. Crimson clover flowers in central Virginia 4/16-5/2, most usually around 4/20. Austrian winter peas bloom at the end of April, and hairy vetch in early May.

Austrian Winter Peas. Photo UAEX Edufarm Ranch Resource Library

More about Austrian winter peas

Austrian winter peas can be sown later than other legumes.

Hardy type of Field Pea. (Black peas)
Winter-kill in zone 6, hardy in zone 7. Hardy to 0°F (-18°C). (Canadian/spring field peas are hardy to 10-20°F (-12° to -7°C))
Can sow several weeks later than clovers
Sow at least 35 days before first hard freeze (25°F/-4°C). In zone 7a, 8/10–11/8
Optimum temperature for germination is 75°F (24°C), minimum germination temperature 41°F (5°C)
Good at emerging through crusted soil
Tolerate a wide range of soil types
Make rapid spring growth in cool weather
Suppress weeds, prevent erosion
High N-fixers – a good stand can provide enough N for the following food crop when incorporated
They fix as much, or more, nitrogen than crimson clover
More dry matter than hairy vetch (which produces more than crimson clover) in the SE
Can be mixed with grasses for vertical support, more biomass and better weed suppression
Suppresses Septoria leaf spot in tomato crops the next year
Blooms late April at Twin Oaks, before hairy vetch
Flowers attract beneficial insects (especially honeybees) and reduce aphids
The tendrils and shoot tips make a nice addition to salads or stir-fries in early spring

Winter rye with Austrian Winter Peas. Photo Cindy Conner

Cautions with Austrian winter peas

Pea seed cannot be stored long. The germination rate could be only 50% after 2 years. Run a germination test if you have seed you are unsure about.
Seeds are large and heavy – high sowing rates (compared to clovers). Cost/area is fairly high, a little higher than vetches
If you haven’t grown peas or beans on that plot for some years, inoculate the seed.
Winter-killed in zone 6, at 0°F (-18°C). For the best chance of winter survival in cold areas, choose your sowing date to get plants 6-8″ (15-20 cm) tall before the soil freezes. (Hairy vetch is more cold-tolerant than AWP.)
Sowing in a mix with a winter grain will improve cold weather survival by reducing soil freezing and heaving.
May not do well if sown in spring – require a cold dormant spell.
Not tolerant of flooding, drought, high traffic, salinity, heavy shade, long cold spring weather below 18°F (-8°C) with no snow cover, or hot (or even warm) weather.
Do not regrow after mowing or grazing once blooming starts.
Peas on their own do not add much organic matter to the soil – the vines break down quickly.
May increase 39 species of pest nematodes, so if you are already having trouble with those, this is not a good cover crop for you.
Susceptible to Sclerotinia crown rot, which can completely destroy crops during winter in the mid-Atlantic. One reason not to grow pea crops on the same land two years running.
Can also be host to Sclerotinia minor, Fusarium root rot and Ascochyta

More resources on Cover Crops

My book Sustainable Market Farming has a chapter on cover crops and many pages of charts about particular options.

The book Managing Cover Crops Profitably (third edition) from the Sustainable Agriculture Research & Education Program (SARE), is the best book I know on the subject. You buy the book for $19 or download it as a free PDF from SARE.

Planning Winter Cover Crops

A cover crop mix of winter rye, hairy vetch, Austrian winter peas and crimson clover.
Photo Bridget Aleshire

If you haven’t already made a plan for winter cover crops, this is a good time to do it. Having plants growing through the winter, or at least into the winter until they get killed by cold temperatures, will improve your soil both physically (the roots hold the soil in place, preventing erosion, and they open up channels that improve the drainage) and biologically (the soil microorganisms thrive when they have active plants to cooperate with, exchanging nutrients). Cover crops will also reduce the number of weeds you have next year, because they crowd out weed seedlings. In some cases they even inhibit weed seeds from germinating.

I have some slideshows about cover crops, and am including one at the end of this post.

Choosing the “perfect” cover crops can be confusing, but any is better than none, so I encourage you to experiment and keep records, so you can improve your choices each year. It helps to know your first frost date, and your winter-hardiness zone (the lowest temperature your garden is likely to encounter). A two-week delay in sowing can seriously reduce the effectiveness of the cover crop, so follow these guidelines if you can.

A cover crop of overwintered oats the year they didn’t die.
Photo Pam Dawling

Short Simple Guide to Winter Cover Crops

If the area has been fully harvested of food crops by 60-80 days before frost, sow a frost-killed cover crop or even a fast-growing food crop. Buckwheat, soy, cowpeas, spring peas, sunnhemp, Japanese millet, sorghum-sudangrass will frost-kill. Forage radish lab-lab bean or bell beans will die back and leave almost bare soil. Don’t sow a winter cover crop yet. If sown too early, oats head up in the fall and even drop seed.
If the area is clear of vegetable crops by 40-60 days before frost, sow oats to winter-kill. If possible add a legume (soy and spring peas are easy, and will be killed by the frost, so they won’t complicate food crops next year). For us with a first frost date of October 14, the cut-off date for oats is September 7. This would be after growing early sweet corn, spring broccoli, cabbage, spring-planted potatoes or early season spinach, lettuce, beets, carrots. Oats will winterkill completely at 6°F (-17°C) or even milder than that, leaving the plot quick to prepare for early crops next year. So plan to put your early crops where you had oats in the winter. See the slideshow for more about oats.
Crimson clover cover crop in flower.
Photo McCune Porter
If the area is ready for cover crops 20-40 days before frost, sow winter wheat. Add a legume such as crimson clover, if you won’t need to prepare the area before it flowers (in central Virginia 4/16-5/2, most usually around 4/20). You get the most nitrogen from the legumes if they reach the flowering stage before you kill them off in spring. If you have a legume that doesn’t reach flowering, it’s not the end of the world, you just get less nitrogen for your money. It is too late to usefully sow cover crops that are not frost-hardy, or even oats, which won’t make enough growth before getting killed.
Cover crop of winter rye, hairy vetch and crimson clover.
Photo Kathryn Simmons
If the area is ready for cover crops up to 10 days past the frost date, sow winter wheat or winter rye and hairy vetch or Austrian winter peas. Winter rye is hardier than any other cover crop and can take later planting dates. But it is a bit harder than wheat to incorporate in the spring. Austrian winter peas can be sown later than other legumes.
If you are up to 3-4 weeks past your average frost date, (we choose November 7 here, where our average first frost is October 14), sow winter rye alone. It’s too late for any legumes.
Cover crop of winter rye still small in March, but holding the soil together.
Photo Pam Dawling
If you are later than 3-4 weeks past your average first frost date, leave the weeds or crop remains growing. It’s too late to sow a cover crop, and you’ll do more harm than good tilling up the soil. You can mow the weeds anytime you see lots of flowers and seed heads. The weed roots will hold the soil together and help feed the soil microorganisms until early spring. Be prepared to act soon in spring, so you don’t get weed seeds.

Quick Guide to Winter Cover Crops.
Pam Dawling

More Options for Each of These Time-frames

60-80 days before frost: You could follow a frost-tender cover crop with an over-wintering cover crop, for best effect. If you leave the dead tender cover crops in place, in early spring the winter weeds will start growing in the open space, so be ready for fast action. For the very earliest spring crops, forage radish lab-lab bean or bell beans will die back and leave almost bare soil. While still growing, they suppress weeds. BUT fast-maturing spring vegetables will not do well with no-till cover crops unless you add N fertilizer, as they need nitrogen more quickly than can be got from no-till.
40-60 days before frost: Austrian winter peas, crimson clover, or red clover are other options for legumes, but they won’t die when the oats do. They are relatively easy to incorporate in spring. Frost-killed cover crops can also be combined with oats. Or for a cover crop to survive the winter, sow winter barley or winter wheat with Austrian winter peas, crimson clover, hairy vetch, red clover, fava beans. Hairy vetch takes a few weeks longer than crimson clover to reach flowering. Which you choose will depend what you want to grow there next spring and when you need to plant it. After oats or other winter-killed cover crop, we like to plant our early spring food crops, peas, cabbage, broccoli, carrots, March-planted potatoes, spinach and the first sweet corn.
Cover crop height and thickness in late April.
Photo Kathryn Simmons
20-40 days before frost: Winter rye, or winter barley are also options for the cereal grain part of the mix, if you have those seeds on hand. In central Virginia, it’s a mistake to sow rye as early as August, as it can set seed. Austrian winter peas, or red clover are other legume options if that’s what you have. Sometimes it pays to use what you already have, as it may not give good germination if saved over to next fall. Winter rye needs 3-4 weeks after tilling in, in spring, to break down and to disarm the allelopathic compounds that stop small seeds germinating. Plan for the next food crops to be ones planted after late April, such as late corn plantings, winter squash, transplanted watermelon, tomatoes, peppers, sweet potatoes, June-planted potatoes, fall brassicas, and second plantings of summer squash, cucumbers, beans.
Up to 10 days past the frost date: it’s too late for clovers. Austrian winter peas winter-kill in zone 6, but are hardy in zone 7. Hardy to 0°F (-18°C). AWP bloom in late April at Twin Oaks, before hairy vetch. Suitable crops in the year before using Austrian winter peas are the late-finishing winter squash, melons, sweet potatoes, tomatoes, peppers, middle sweet corn, June-planted potatoes. The same group of crops are suitable for following AWP, as they are planted after May 1. You can sow AWP several weeks later than clovers, but at least 35 days before first hard freeze (25°F/-4°C) – in zone 7, 8/10–10/24 (11/8 is sometimes OK)
Winter rye headed up. Mow or turn it under very soon! Don’t let it shed seed.
Photo Pam Dawling
Up to 3-4 weeks past your average frost date: no really, it’s too late for any other cover crop. If you don’t have winter rye, don’t till! Leave the weeds, see below.
Later than 3-4 weeks past your average first frost date: no, really, do not till! You could mow and tarp, to kill the weeds before spring. I’m not sure what the soil life thinks about that, though! You could mow again in early spring, or till and sow oats, if you won’t be planting a food crop in the following 8 weeks, giving the oats time to make respectable growth before turning them under.

Create a crop rotation for vegetables that includes good cover crops

If you include winter cover crops when planning a crop rotation for your vegetables, you can tweak your plan to maximize your cover crop opportunities. Here’s the steps:

Figure out how much area is needed for each major crop (the ones needing the largest amount of space).

Measure and map the space available
Divide into equal plots big enough for your major crops
Group compatible crops together to fill out each plot
Set a good sequence, maximizing cover crop opportunities
Include best possible cover crops at every opportunity
Try it for one year, then make improvements

For more details, see my slideshow Crop Rotations for Vegetables and Cover Crops on SlideShare.net

Advanced Options for Winter Cover Crops

Sweet corn with undersown soybean cover crop. Photo Kathryn Simmons

Undersowing

Sometimes you can undersow the cover crop between the rows of a growing food crop, to take over after the food crop dies of frost or mowing. We do this with our last planting of sweet corn, and with fall broccoli and cabbage.

Timing is critical: Sow the cover crop late enough to minimize competition with the food crop, but early enough so it gets enough light to grow enough to endure foot traffic when the food crop is harvested. The leaf canopy of the food crop should not yet be closed. Often the best time is at the last cultivation, often about a month after planting the food crop. With vining food crops, it’s important to sow the cover crop before the vines run.

Choose vigorous food crops, but cover crops that are only moderately vigorous. Ensure the seedbed is clean and the soil crumbs small enough. Use a high seeding rate, whether broadcasting or drilling, and irrigate sufficiently.

A no-till cover crop mix of winter rye, hairy vetch, Austrian winter peas and clover.
Photo Bridget Aleshire

No-till Winter Cover Crops

In the spring, kill the cover crop without tilling it in, and plant food crops into the dying residue. There are three ways to kill cover crops without herbicides:

Winter-killed cover crops for early spring food crops
Mow-killed cover crops.
Roll-killing (but it usually requires special equipment).

We have had one year in 10 as a no-till year. We use no-till cover crops before Roma paste tomatoes, which are transplanted in early May. We don’t need early-ripening for these, making them a good no-till food crop. The soil under no-till cover crops stays colder than tilled soil, slowing the plant growth down.

Late-spring transplanted crops such as late tomatoes, peppers, eggplant, Halloween pumpkins, or successions of cucumbers and squash can do very well after a winter-hardy legume-grass mix no-till cover crop.

To be an effective mulch, you need to get a thick sturdy stand of cover crops, which means sowing in plenty of time, and being generous with the seed. To make the timing work, you need a previous food crop that finishes before the sowing date 4-5 weeks before the average frost (that’s September 7-14 for us).

Timing is also critical in the spring. For maximum N, the legumes in the mix will be flowering right when you need to plant the food crop. Mow the cover crop mix close to the ground, and plant right into the stubble. Transplants or big seeded crops work well. The ground will be relatively hard – you probably can’t make a furrow for small seeds).

It’s not all over with the weed-prevention after that. In our humid climate the no-till mulch biodegrades after 6-10 weeks. In July we roll hay between the rows, to top up the mulch.

Cover Crops for Vegetable Growers 2019 60 mins

Article on clovers, sowing of clovers, arrival of pickleworm

The September issue of Growing for Market magazine is out, including my article about growing clovers for cover crops, which I mentioned on my blog last week. I wrote how we had ideal “transplanting weather” (rain) when we needed to top up the transplanted cabbage and broccoli, and then “ideal hoeing weather” (not a cloud in sight) when we started removing the rowcovers and hoeing the rows. We tilled between the last rows in the end, as the grassy weeds got ahead of us (all that rain the week before) and we couldn’t get done with the wheelhoes in time, while the weeds were small. We got “perfect clover broadcasting weather” yesterday (drizzle), and I managed to get the clover mix sowed after lunch. I was in my raincoat, with a bucket of seed under my arm, striding forth. I ended up happy, with lots of mud and clover seed between my toes! It feels good to have that job done. We’re having more drizzle this morning – seems perfect to get the clover seed to germinate there on the surface, without drying out. It’s saving a lot of fussing with overhead irrigation.

Crimson clover is a beautiful and useful cover crop. Credit Kathryn Simmons — Crimson clover is a beautiful and useful cover crop.
Credit Kathryn Simmons

And you can read more about undersowing clovers for all year cover crops (Green Fallow), and other uses of clovers for winter cover crops in Growing for Market magazine. For next month I’m writing about another of our favorite leguminous winter cover crops, Austrian winter peas.

The September issue also has an article generated by a competition among readers to send in ideas for easy DIY hoophouse ventilation. Ideas include high end wall windows (Tennessee), sidewalls rolled up onto pipe hangers (Louisiana), internal end-wall sliding doors (Alaska) and roll-up ridge vents (North Carolina).

Chris Blanchard writes about increasing production efficiencies and scaling up for increased production. He wisely recommends first taking a cool calm review of how your current plans have been working, and which bits haven’t been working. Don’t expand unless you have a successful grasp of what you are already doing. If you are unsure, focus first on improvements, then revisit the idea of expansion. Get better before getting bigger. Chris has a lot of wise advice and this is a good time of year to review and plan for next season. he recommends keeping a file folder labeled “Painful Things to Remember in November”. You drop a note in the folder whenever you hit a problem during the year, so that in the winter you can be reminded (helpfully!) and you can devise solutions or changes before next year. I like this. I try to do some of this, but a dedicated folder, or maybe a box, like a Suggestions Box, in the shed, for any of the crew to drop in a note. . .

There is an article on the food safety risks introduced by irrigation water and by compost, written by Meredith Melendez and Wesley Kline from Rutgers NJAES Co-operative Extension Service. We all need to be reminded to take appropriate care to make sure our food really is as healthy and good for us as we want it to be.

Gretel Adams writes about preparing for Mothers’ Day flowers – yes, now is the time to plant for that event, one of the biggest in the flower farmers’ calendar.

Large pickleworm larva. Photo University of Florida

And then – the pickleworm has arrived in our part of Virginia. This tropical insect, Diaphania nitidalis overwinters in south Florida (and maybe south Texas) and spreads up the east coast each year. It regularly reaches South and North Carolina in August or September. It reached here in the first week of September. This is the first time I’ve seen this pest on our farm. I’ve read that it can reach as far north as Michigan and Connecticut some years. We’re reassured that it can’t overwinter here, and that we could get at most 3 generations. Sort of reassured. The adult is a night-flying moth, which lays tiny eggs on buds and flowers. Despite the name, this pest likes yellow squash more than pickling cucumbers. (And winter squash, gherkin and cantaloupe can be colonized if necessary.)We first found ours on Zephyr yellow squash and initially the neighboring Noche zucchini was untouched. But yesterday some of the zucchini also had holes.

Yes, I’m getting to that. When the eggs hatch, the small multi-spotted white, brown-headed larvae/caterpillars burrow into a squash, where they eat and grow, and do what everyone does, poop. If you don’t act quickly, the inside of the squash gets tunneled out, until the fifth instar, up to an inch long, is ready to pupate. The fifth instars are the easiest to find, being biggest, although they have lost their spots and are now colored according to what they’ve been eating, somewhere in the pale yellow-green part of the spectrum. The dark copper-colored pupae (haven’t seen those yet) nest in a leaf fold or among dead plant mater, for 8-9 days, then a new adult moth emerges. What’s a busy organic (small o) farmer to do?

Soldier beetles and some carabid beetles eat them. Steinerama carpocapsae nematodes attack them. We’d have to buy those in. Bacillus thuringiensis (Bt) would kill them if we could reach them, but they are living a sheltered life inside our squash! We could cover the plants every night and uncover them every morning to let polllinators in, but oh dear, the days are so full already! We decided for this week, we’ll just harvest the squash a bit smaller than usual and see how that goes. Maybe not many moths arrived, and frequent harvesting (and slicing up of holed squash) will stop any future generations. Slicing the squash at the level of the hole does usually decapitate the larva. I wonder how long the moths live for?

The eXtension website publication Biology and Management of Pickleworm and Melonworm in Organic Curcurbit Production Systems by Geoff Zehnder of Clemson U provides the useful information that “research by Brett et al. (1961) demonstrated marked resistance to pickleworm in the following varieties: Butternut 23, Summer Crookneck, Early Prolific Straightneck, and Early Yellow Summer Crookneck. The varieties more susceptible to pickleworm are Cozini Zucchini, Black Caserta Zucchini, and Benning’s Green Tint Scallop squash.” I might add Zephyr squash. Spinosad might be effective, but as with Bt, I think it would be difficult to get the spray on the beasties as they are inside the squash.

For pictures of the damage, see Sunninglow Farms blog. They are in Florida and posted this in April. I shouldn’t complain too loudly. It is September here.

Pickleworm damage to yellow squash. Credit Sunninglow Farms — Pickleworm damage to yellow squash.
Credit Sunninglow Farms

Now I must get on with finishing preparing my powerpoints for Heritage Harvest Festival and Mother Earth News Fair in Pennsylvania. Hope to see some of you there!

Sweet potato harvest – all in!

OLYMPUS DIGITAL CAMERA — Our sweet potato harvest well underway.
Photo credit Wren Vile

Usually sweet potatoes are harvested the week the first frost typically occurs. In anticipation of frosts (that didn’t happen) on Sunday and Monday nights, we harvested this week. Contrary to myth, there is no toxin that moves from frozen leaves down into the roots. On the other hand, cold injury can ruin the crop, and roots without leaf cover are exposed to cold air temperatures, and have lost their method of pulling water up out of the soil. Cold wet soil can quickly rot sweet potatoes (I know, it’s happened here).

To harvest, we first remove the vines from the area to be harvested that day. There is usually 3 afternoons’ digging for ours, and we want to leave live vines to protect the rest of the crop overnight. We use pruners to snip the vines where they emerge from the soil, leaving stumps to show where to dig. We roll the vines into the spaces between the rows. Using digging forks, we carefully dig up the roots, which grow in the ground in a bunch-of-bananas shape. We want to select good potatoes for seed, and we grow several different kinds (Georgia Jet, Beauregard, and a couple of heritage varieties whose names we don’t know), so we make sure not to mix potatoes from different rows. As we dig, we set the potatoes out beside the spot where they’ve grown, one clump per plant, so it’s easy to identify the most productive plants.

It’s important not to bruise the roots, or to leave them exposed to temperatures higher than 90°F (32°C) for more than half an hour, or they will get sun-scald. Below 55°F (13°C), they’ll get chilling injury. We also avoid any abrasion of the skin, which is very fragile at this stage. We leave the sweet potatoes to dry on the ground for 1-2 hours, unless the weather is unsuitable. This year we had ideal weather, not too hot, not too cold; breezy enough to dry the skins, sunny.

We want to grow our own slips (baby plants) next year, so we save at least 1 root per 5 slips wanted. (1 good slip every 16″.) So to plant 800 row feet, (600 slips), we save 100 each of our two main varieties and 20 each of the two heirlooms. That should be plenty. Some will shrivel or rot, so we allow a margin. We don’t save for seed any roots that look diseased. We choose plants with a high yield and no string (rat-tail) roots. From these plants, we choose small-medium sized potatoes with typical shape and color.

When grading and crating the roots in the field, we first choose the seed potatoes, and then sort storable from “Use First” roots. Large open broken surfaces will cure and can be stored, but any roots with soft wet damaged areas or deep holes (whether from voles, bugs or fork tines) will not store, and should be graded out, for composting or immediate use. We sort into 4″ deep wood flats or 5″ plastic crates for curing, and buckets for the “Use First” category.

Immediately after harvest, we took the boxes of sweet potatoes into a warm damp basement below the dining hall, to cure. This allows the skin to thicken, cuts to heal over and some of the starches to convert to sugars. Uncured “green” sweet potatoes are not very sweet at all, and are better used in dishes where they combine with other foods. A baked uncured sweet potato is a sad disappointment.

We stack our boxes of roots on pallets, and put wooden spacer sticks between boxes in each stack, to ensure air flow. We get quite good temperatures, but keeping humidity up is difficult for us. We cover the flats with newspaper to hold in some moisture. The best result seems to come from splashing water on the concrete floor several times each day. We use box fans to improve the airflow, and the basement already has some natural ventilation.

Ideal conditions for curing are 85-90°F (29-32°C), and 80-95% humidity for 4-7 days, with some airflow and ventilation. Curing takes longer if conditions are less then perfect. The length of the curing period also varies with the dryness of the soil just prior to harvest. We usually reckon on 10-14 days. During that time, we’ll be taking turns to stoke the stove in the basement to keep the temperature up.

So – how did we do this year? Middle of the road, I’d say. Decent yields, but not a bumper crop – we still had empty boxes left over. The deer were regularly eating our vines until quite recently. Last year we had a dog to chase the deer off, but he met with a road accident. His replacement was old, and she just wanted to be a pet, so we had deer again. We used drip irrigation and biodegradable plastic mulch this year, and did a good job of weeding, so I put the lower yields down to deer damage.

Last year’s (weedier!) sweet potato field.
Photo credit Kathryn Simmons

Now the harvest is complete, we will disk the area and sow cover crops. It’s too late in the year for oats. We can sow wheat, winter rye and Austrian winter peas up till 10/31. We prefer winter wheat after the sweet potatoes, because we’ll use that area next year for spring white potatoes in mid-March, and rye takes too long to break down early in the spring.