Hoophouse Sliding Doors, Vegetable Weevil Larvae – Seasonal Challenges!

September 6 sowing of tatsoi and our August 28 sown catch crop of Tokyo bekana. We harvested the last of this catch crop October 14 and sowed turnips, Photo Pam Dawling

October is the busiest month in our hoophouse! The bed prep, sowing and transplanting keeps us busy for 3 or 4 hours a day. Add in harvesting (peppers, radishes, salad crops) and hand-watering of new plants, and we’re there for a good half of each day. And then there are extra challenges. Yesterday, in tightening one of the strings that mark the bed edges, I managed to hammer a 6” sod staple right through the irrigation main line tubing, which was below soil level. I can hardly believe I did that! I even thought “Be careful not to stab the water pipe!” So I had to dig it up, find a coupler and fix it right away. Because at this time of year, we rely on the irrigation for all the new plants.

And the nights are getting colder. We intend to close the doors every night when the temperature will be below 50F (10C), and the windows if the temperatures will be below 45F (7C). We have been converting the doors at one end from hinged to sliding doors. They’re hanging on their tracks, but one door is jamming in the track, and we need more than a cursory look to fix the problem. So meanwhile, only 3 of the 4 doors close!

One of the new sliding doors on our hoophouse.
Photo Pam Dawling

Hoophouse Doors

My book The Year Round Hoophouse, has a chapter on making end walls, including doors and windows. Writing that helped me decide to change our east doors. Here’s an excerpt from that chapter:

 “For our 30′ (9.1 m) wide gothic hoophouse, we have a pair of hinged double 4′ x 8′ (1.2 x 2.4 m) doors at each end. Our doors open out and have to drag over the grass outside. We have found “rising butt” hinges to be helpful here. As the door opens, it rises on the curved base of the hinge, giving a little extra clearance above the ground. Each door fastens with a hook and eye to the wall when open (it will get windy!).  I recommend considering sliding doors, with the track and hardware on the inside, if the tunnel is wide enough for the track needed to carry the size of doors wanted. This avoids problems in many weathers: rampant grass-growing season, snow season, strong winds. Some people purchase storm doors and use those, but they are not very big. Anyone with basic carpentry skills can make simple door and window frames, as they will be covered both sides in lightweight plastic and not need to be extremely strong.”

View through the old hinged hoophouse doors in a previous December.
Photo Kathleen Slattery
Close up of a roller bracket attaching our hoophouse door to the track.
Photo Pam Dawling
  •  Matt Kleinhenz of the Ohio State University Vegetable Production Systems Laboratory, has a slide show of end wall designs High tunnel end wall and door types images,
  • ·        David Laferney of The Door Garden, in Building Greenhouse Doors,, 2008 has clear photos of hinged door construction for beginner carpenters.
  • ·        Hightunnels.org has various articles on construction, including a slideshow Images of High Tunnel Doors.
  • ·        For more to read, see M D Orzolek, High Tunnel Production Manual. See Chapter 3: High Tunnel Construction

Vegetable Weevil Larvae

A new Tokyo bekana transplant attacked by vegetable weevil larvae October 10
Photo Pam Dawling

Sometimes in the cool weather we have problems with this secretive pest chewing holes in brassica leaves at night. The larvae live in the soil and stay underground or deep in the heart of the plants during the day, so if your leaves are holey, but you can’t find any culprits, you can suspect vegetable weevil larvae. They especially like turnips, pak choy and the flavorful mustardy greens. We sprayed with Spinosad last Monday, then again on Friday, and this week (Monday and Tuesday) I’m not seeing any new holes.

Debbie Roos of Growing Small Farms wrote about this pest in “The Bok Choi Problem” which has good photos and a Description and Biology of the Vegetable Weevil

Vegetable weevil larvae in action. From Growing Small Farms
Photo Debbie Roos

 

Cooking Greens in October

 

Vates kale in the fall.
Photo Bridget Aleshire

Cooking Greens to Harvest in Central Virginia in October

Beet greens, broccoli, cauliflower, cabbage, chard, Chinese cabbage, collards, kale,  komatsuna, Maruba Santoh, pak choy, senposai, spinach, tatsoi, Tokyo Bekana turnip greens and Yukina savoy can be available here all month (and perhaps longer, depending on the temperature). OP Yukina Savoy seems more cold-hardy  and bolt-resistant than the hybrid Koji.

The new outdoor greens this month are tatsoi, kale, spinach, collards, and mizuna (if we have that outdoors).

Eat-All Greens harvests can start, if you sowed some last month. When we sowed some on September 16, we got two harvests in October and several in November.

From the hoophouse we start to harvest spinach, tatsoi, and leaves of Tokyo bekana.

Cooking Greens to Sow in Central Virginia in October

This month we finish sowing spinach and kale for overwintering outdoors (10/30 is our last chance). No more outdoor sowings until spring!

“Filler Greens”

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

On October 10, we sow Brassica fillers #1. These are short rows of senposai, Tokyo bekana, Yukina Savoy, Maruba Santoh,  to use to fill gaps later during the winter as soon as they occur. We simply dig them up, replant where needed and water well. Alternatively you could keep some plug flats of these plants handy. Bare-root transplanting is much easier than many fear.

During December we use the “Filler” greens plants to replace casualties and harvested heads of Tokyo bekana, Maruba Santoh, Chinese cabbage, Pak choy, Yukina Savoy and tatsoi daily. We stop filling gaps in these early harvest crops on December 25, as they will bolt in the hoophouse conditions in January at the latest.

We continue to fill gaps elsewhere with senposai until January 25. Asian greens don’t make good growth before bolting if transplanted after January 25. From January 25 to February 20 we fill all gaps everywhere with spinach transplants

Hoophouse Bed preparation and Planting

In the hoophouse we have a lot of bed preparation (all the beds except the Early Bed which we plant in September), as well as transplanting and sowing.

On October 14, we sow turnips #1: Red Round (1 row on North), Hakurei (2 rows South). Oasis, White Egg.

On October 20, we sow Filler Greens #2.

By October 23, we clear and prepare two more beds and sow spinach #2; tatsoi #2, turnips #2, chard #2 and perhaps Frills (Frilly Mustards) #1.5.

Brassica (Mustard) Salad Mix

Interesting mustard mixes are sold for salad mixes. We often mix our own Brassica Salad Mix from leftover random brassica seeds. For a single cut, almost all brassicas are suitable – just avoid turnips and radishes with prickly leaves! We sow between October 2 and November 14 for harvests during the winter, and from December 4 to February 12 for March and early April harvests.

We could, but so far we haven’t, sow Eat-All Greens in hoophouse in October.

Catch crops

Useful if a crop fails, or you have an empty space. Don’t delay, as rates of growth slow down as the temperatures and daylight decrease. Don’t expect much from sowings during the Persephone Days (less than 10 hours daylight).

Tokyo bekana is a quick-growing Asian green, for cooking or salads.
Photo Twin oaks Community

This year we grew an early catch crop of Tokyo bekana when we realized we had space that wouldn’t be needed till mid-October (for turnips). We direct sowed it August 28, weeded and thinned to 1” (2.5 cm) on September 5; weeded and thinned to 3” (7.5 cm) on September 16, using the small plants for salad. We need to clear this crop by the middle of October to sow the turnips, and the Tokyo bekana has got to a fine size.

  • Ready in 30–35 days in fall, longer in winter: brassica salad mixes, spinach, chard, salad greens (lettuce, endives, chicories), winter purslane., kale, arugula, radishes (the fast small ones and the larger winter ones), many Asian greens: Komatsuna, Maruba Santoh, mizuna, frilly mustards, Senposai, tatsoi, Tokyo Bekana and Yukina Savoy.
  • Ready in 35–45 days in fall: corn salad, land cress, sorrel, parsley and chervil.
  • Ready in 60 days in fall: beets, collards, kohlrabi, turnips

Cooking Greens to Transplant in Central Virginia in October

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

In our hoophouse in early October, we transplant Tokyo Bekana, Chinese cabbage, Pak choy, Yukina savoy #1,  using plants which we sowed outside under insect netting.

By October 13, we transplant chard #1, Frills #1, and Red and White Russian kales, from our outdoor nursery seedbed.

By October 21, we clear and prepare another bed and transplant 1/2 bed kale, plus Yukina Savoy, and frilly mustards. (This is our favorite crop selection to suppress nematodes),

By October 23, we clear and prepare two more beds and transplant senposai and Yukina Savoy #2 from the outdoor nursery bed.

Other Cooking Greens Tasks in Central Virginia in October

October is our month to weed and thin the fall crops in the outdoor raised beds, especially spinach and kale. We thin kale to 12” (30 cm); perhaps more space would be better, although Vates is a dwarf variety.

We put rowcover over any beds of pak choy, Chinese cabbage or Tokyo bekana we have that year. Later we weed (again!) and cover the spinach for faster growth, but leave the kale uncovered after a bad experience of Vates kale with rowcover fibers mixed in. The cooks didn’t love us!

Galinsoga dies with the frost.
Photo Wren Vile

We prefer to wait to cover spinach after frosts kill the galinsoga. As well as raised beds, we plant spinach in our cold frames, making good use of the space until the frames are needed in spring for hardening off transplants.

We roll, label and store drip tape from the fall broccoli and cabbage

Special Cooking Greens Topic for October: Get Soil Tests; Be Ready for Cold Nights.

October is a good month to do soil tests, when the soil is not too wet, and the soil temperatures are still warm (the soil life is active).

Weather Forecasting

We use Wunderground, but subtract 5F° 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.

See Weatherspark.com for the typical ranges of weather in your area:

Savoy cabbage with frost.
Photo Lori Katz

Predicting Frost

Frost is more likely at Twin Oaks if:

  • The date is after 10/14 or before 4/30 (our average first and last frost dates).
  • The Wunderground forecast low for Louisa Northside is 37°F (3°C) or less.
  • The daytime high temperature was less than 70°F (21°C).
  • The temperature at sunset is less than 50°F (10°C).
  • The sky is clear.
  • The soil is dry and cool.
  • The moon is full or new (maybe to do with tides and gravity?).
  • 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.
  • The dew point forecast is low, close to freezing. Frost is unlikely if the dew point is 43°F or more.

Watch for cold night temperatures and decide which crops to harvest, which to cover, which to abandon:

In a double-layer hoophouse (8F/5C warmer than outside) plants can survive 14F/8C colder than outside, without extra rowcover; with thick rowcover (1.25 ozTypar/Xavan) plants can survive at least 21F/12C colder than outside.

The hoophouse winter crops are an important part of feeding ourselves year-round

Each winter I update my Winter-kill Temperatures of Cold-Hardy Vegetables.

Here are some early winter numbers for killing temperatures outdoors (without rowcover unless otherwise stated). Your results may vary!  Let me know!        

35°F (2°C): Basil.

32°F (0°C): Beans, cucumbers, eggplant, melons, okra, peppers, tomatoes.

27°F (–3°C): Many cabbage, Sugarloaf chicory.

25°F (–4°C): Some cabbage, chervil, chicory roots for chicons and hearts, Chinese Napa cabbage, dill, endive, some fava beans, annual fennel, some Asian greens (Maruba Santoh, mizuna, most pak choy, Tokyo Bekana), some onion scallions (many varieties are hardier), radicchio.

22°F (–6°C): Some arugula (some varieties are hardier), Bright Lights chard, large leaves of lettuce (protected hearts and small plants will survive colder temperatures), rhubarb stems.

20°F (–7°C): Some beets, broccoli heads (some may be OK to 15°F/-9°C), Brussels sprouts, some cabbages (the insides may still be good even if the outer leaves are damaged), celeriac, celtuce (stem lettuce), some head lettuce, some mustards/Asian greens, flat leaf parsley (curly parsley is hardier), radishes, most turnips.

15°F (–9.5°C): Some beets, beet greens, some broccoli, some cabbage, rowcovered celery, red chard (green chard is hardy to 12°F (-11°C)), cilantro, endive, some fava beans, Russian kales, kohlrabi, some lettuce, especially medium-sized plants with 4-10 leaves, curly parsley, rutabagas if not covered, broad leaf sorrel, turnip leaves, most covered turnips, winter cress.

Frosted daikon radish.
Photo Bridget Aleshire

Frilly Mustards in our Winter Hoophouse

 

Hoophouse frilly mustard, mizuna and lettuce mix in our hoophouse in December.
Photo by Kathleen Slattery

I have written before about our love of Ruby Streaks, a beautiful dark red frilly mustard. We also like Golden Frills and Scarlet Frills. We like Mizuna too. It was our “gateway frilly mustard”!

Green mizuna in our hoophouse in November.
Photo Pam Dawling

Mizuna – the Gateway Mustard.

Mizuna is a very mild flavored crop, with thin juicy white stems and green ferny leaves which add loft in salad mixes. (“Loft” is the word for the “puffiness” of frilled salad crops, helping them occupy space and not collapse in the bottom of the bag or bowl like wet green corn flakes.) This tolerant crop is very easy to grow, tolerates cold wet soil, and variable weather. It is fairly heat tolerant (well, warm tolerant), and cold tolerant to 25°F (-4°C).

We used to just grow just one planting, sowing it outdoors September 24, transplanting it into our hoophouse October 22. It regrows vigorously after cutting and we harvest leaves from November 27 to January 25 or even to March 7, when it becomes a mass of small yellow flowers (edible!). In the winter, once the plant gets bigger and bushier, we switch from harvesting individual leaves to a method we call the “half-buzz-cut.” We gather the leaves on one side of the plant and cut them with scissors about an inch above the soil. Then we chop them into our salad mix harvest bucket. The plants look odd with half their leaves still full-size and half shorn, but this method seems to help the plant regrow quicker. The big leaves can photosynthesize and feed the regrowing leaves.

Next we tried Purple Mizuna, but we were disappointed with the weak color and a constitution less-robust than green mizuna.

Ruby Streaks and other Frilly Mustards

After a few years of growing mizuna, we discovered Ruby Streaks. It has a much stronger color, and I admit, a much stronger flavor. Our diners don’t generally like pungent greens, but this one, cut small and mixed with other salad greens, gained wide approval. We have moved on to include Golden Frills and Scarlet Frills, and for a while Red Rain. We find the Scarlet Frills and Golden Frills bolt (go to seed) later than Ruby Streaks and Mizuna.

Ruby Streaks beside green mizuna.
Credit Ethan Hirsh

Adding a Second Sowing

We added a second sowing, this one direct-sown in the hoophouse, on October 30, and the next year shifted the date to November 9. These direct-sown mustards can be used for baby salads after only 21 days (when thinning the rows, for instance). Thin to 8″–12″ (20–30 cm) apart, to grow to maturity in 40 days. We sow mizuna and the spicier mustards at the same time, usually 6 rows to a 4’ (1.2 m) wide bed, maybe a total row length of 50’ (15 m). This sowing gives us harvests from February 26 to March 24, several weeks later than the September 24 sowing.

Golden Frills and Ruby Streaks in our hoophouse.
Photo Pam Dawling

Fighting Nematodes

When we learned our hoophouse soil had nematodes some years ago, we searched for resistant crops and were happy to learn that Brassica juncea greens were resistant. Although mizuna is not B. juncea, the more pungent frilly mustards are, so we focused on growing those, and ignored mizuna for several years.

Adding a Third Sowing

We were looking for a late winter nematode-resistant crop to follow our Koji, which I think bolts up to a month earlier than my long-time favorite Yukina Savoy. We tried the frilly mustards, sown February 1, and they were very successful. We got harvests from March 24 to April 23, a very worthwhile month of greens! I like greens that are harvestable in March and April, because this is really our Hungry Gap, the time when the stored crops are running out and the outdoor spring-planted ones haven’t really got producing much yet. I’m a bit suspicious of our record-keeping on the April 23 date – I suspect it was really over before that. It seems unlikely that this sowing lasts 30 days when the second one only lasts 26 days.

 

By trial and error, we found that our last worthwhile hoophouse sowing date for frilly mustards is February 12.

Bye bye mizuna! Bolting mizuna (our third planting) in our hoophouse in mid-April.
Photo Pam Dawling

Trying a Fourth Sowing

As part of a renewed effort to manage the nematodes, last year we added in a fourth sowing, on October 30. I haven’t got any records for that harvest to hand. I do remember though, that we had about as much “Frills” (as we now call them) as we could eat. We planted 30’ (9 m) in the first sowing, 50’ (15 m) in the new extra planting, 48” (14 m) in the November 9 sowing, and a whopping 120’ (36 m) in the February 1 sowing.

Book Review: For the Love of Pawpaws by Michael Judd

For The Love of Pawpaws: A Mini Manual for Growing and Caring for Pawpaws From Seed to Table

Michael Judd, Published August 2019 by Ecologia, Distributed by Chelsea Green Publishing, ISBN 978-0-578-48874-5.

This wonderful new book is inspiring and appetizing, practical and beautiful. About 150 pages of glorious photos, technical details, mouthwatering recipes, and anything else you might need to start growing pawpaws or to make better use of wild pawpaws on neglected trees nearby. Here you can learn the reasons to plant named cultivars that have been selected for size, flavor, and high yields.

Michael Judd, his wife Ashley and son Wyatt live at Long Creek Homestead in a round house on a homestead in the Maryland Appalachian foothills, where they grow many food trees and other fruits, and hold an annual Pawpaw Festival each September .

Pawpaws are related to custard apples and cherimoya, in the sugar apple family, and yet they grow in the temperate zone, having moved north as Ice Age glaciers receded. Flavors of mango, banana and pineapple come from this creamy fruit. But if you don’t know what you’re doing and you let them get bruised, or you pick them under-ripe, you can end up with a bitter taste in your mouth, or a bellyache. So get this book!

Learn how to spot wild pawpaws in a forest edge or along a river bank. They need full sun to develop good flavor, although the trees will grow in the shade. If you want to grow your own, you can of course grow them from wild seeds (that you keep damp and plant right after eating the fruit).

Growing Pawpaws
The four key elements of successful pawpaw production:
  1. moisture (minimum of 32” (81 cm) annual rainfall or access to continuous soil moisture);
  2. well-drained soil, preferably fertile;
  3. warm humid summers with 160 frost-free days;
  4. cold winters including some freezing temperatures and at least 400 chill hours.

USDA Winter-hardiness zones 5-9 are most-suited. If these factors are addressed, the pawpaw can be an easy-care fruit tree. We have all those factors in our area of central Virginia, and we have wild trees along the South Anna river. We also have cultivated varieties planted near our houses. Given the right conditions, pawpaw trees grow to an attractive 25 ft (7.6 m) pyramid shape, and can bear 50 lbs (23 k) of fruit each year.

It’s best to have two or more genetically different trees close together, for good cross-pollination and heavy fruit set. Individual flowers cannot pollinate themselves, and although each tree can self-pollinate, the yield might not be large. The unusual purple-brown flowers are fairly inconspicuous.

The chapters on growing the trees includes collecting seeds, germinating them, planting, grafting, choosing rootstock and the importance of soil fungi. Read about companion planting with nitrogen-fixing plants (such as lead plant, false indigo, black locust, which will need cutting back later) and soil-covering “mulch” plants (such as comfrey, yarrow, lemon balm, fuki, white clover). The tree-care chapter includes fruit thinning, and pruning (avoid climbing these brittle trees by keeping them 8 ft (2.4 m) tall).

Cultivated Varieties

If you have only eaten wild pawpaws, you’ll be amazed at the cultivated ones – much bigger, with a more balanced sweet flavor, delicious aroma and smooth texture. Michael offers advice on choosing a variety and choosing and planting potted seedlings. He introduces us to Neal Peterson, who he calls the Mahatma Pawpaw. Neal has created most of the best pawpaw cultivars. I profiled his work here.

Factors to consider include when the fruit ripens and whether all fruits ripen within a small window; whether the fruit softens quickly; whether the skin is thin (undesirable if you are selling or attempting to store the fruit); whether they tend to split in rainy weather; whether they need a lot of fruit thinning to preserve the health of the tree; how big the fruit is (4-6 oz (114-170 g)? 8oz (227 g)? 16 oz(454 g)?) ; the seed:pulp ratio (some big fruits have huge seeds – an ideal range is only 4-8% seeds). Michael offers profiles of the seven Peterson cultivars, the three Kentucky State University cultivars and Jerry Lehman’s two named cultivars. For the wannabe-grower in a hurry, there is a summary of the best cultivars for several factors, and for the person who has no time to read or experiment, Michael suggests sticking with the long-proven wild-sourced cultivars Overleese, Sunflower, PA Golden and NC-1.

Harvesting Pawpaws

Harvesting is both art and science. Under-ripe pawpaws can lead to belly-ache. Mishandling pawpaws can quickly lead to poor results. Windfalls that have lain on the ground for several days will likely be funky in smell and bitter in taste – don’t let your first experience of pawpaw be like this! The ideal is to hand-pick ripe fruit, and as the transition from rock-hard unripe pawpaws to ripe is very sudden, you’ll end up checking the same fruits more than once. Some cultivars change color, others don’t. Check daily! Ripening can finish later if they have begun ripening before you pick. The harvest period lasts 2-4 weeks (July in the Deep South, late August and early September in central Virginia, October in the Great Lakes region).

Photo Michael Judd
Post-harvest

Be very gentle in handling these delicate fruits. Eat within 72 hours of picking or refrigerate (for 1-3 weeks, with the longer period being in a large cooler with a big air volume) Pawpaws exude large quantities of ethylene when ripening. This colorless, odorless gas causes other crops in the same storage space to ripen more, or to sprout, or in the case of carrots, to taste bitter. Alternatively, pulp and freeze (or freeze and pulp). This is one of the places where you learn time- and money-saving secrets – freeze the fruits whole, remove from the freezer after 12 hours, warm them for half an hour, then peel as if they were potatoes, pry them open and pop the seeds out cleanly. Put the frozen chunks back into the freezer until you have more time. There are tips about keeping the yellow color, and which food mills and sauce-makers can pulp pawpaws.

There’s info on the nutritional content of pawpaws: 3.5 oz (100 g) provides 80 calories, including 1.2 g of protein and fat, and all of the essential amino acids.

Pawpaw Recipes

The next section of the book is recipes and mouth-watering photos. (Cheesecake! Ice-cream!) First are the recommendations on eating pawpaws fresh off the tree, and in other ways raw. Next are the cautions about baking with flour which can mask the more subtle flavors and leave something that could be mistaken for banana pie or butterscotch tart. There are vital guidelines on how to use pawpaw pulp in recipes, and what not to do (do not boil or dry the fruit). Many pawpaw recipes are high in cream, butter and sugar, which you might relish. However, here are also some recipes that are healthier, including some vegan recipes. There’s also a simple recipe for unsweetened pawpaw jam, which they cook on a rocket stove, and one for pawpaw butter that includes some sugar and some bourbon. And beer, mead and kombucha.

Pawpaws and Permaculture

The first appendix is “Pawpaws and Permaculture” – here’s one of the special things I like about this book. First we learn about this particular tree crop, and bit by bit we see practices we associate with permaculture – swales, mulches, companion plants. It all makes sense. Here is an explanation for those of us who are not filled with religious zeal at every awed utterance of the word “permaculture”. I’m not the type to believe a theory then fit my practice into that theory. I’d rather practice, observe, learn about options, choose from the most likely to succeed, evaluate, tweak, do a small experiment with a different method, and so on. Here’s “Permaculture for the Rest of Us.” In the past I have been put off by the religious zealotry of some permaculturists – the all or nothing, good or bad, I-know-better-than-you attitude, which does not lead us closer to co-operation, mutual learning or world peace. This book is refreshingly different from that branch of permaculture and I am very grateful for that.

I also got insight into what permaculturists mean when they talk of “Food Forests”. They don’t actually mean acres of food trees. They mean small clumps of trees within a lawn. Agroforestry is the name for the type of farming that includes trees as windbreaks and crops, and pawpaws are a good candidate for inclusion. Goats don’t eat pawpaw trees! In this part of the book, the place for pawpaws in Hügelkultur beds (piles of wood covered in soil); greywater berms (shallow trenches funneling sink water into the landscape; and rain gardens (areas that store rainwater in the soil to irrigate plants) is explored.

Commercial Pawpaw Farming

For those venturing into commercial pawpaw growing and marketing, there is a profile of Deep Run Pawpaw Orchard in Maryland, where trees are 8 ft (2.4 m) apart in rows 15 ft apart (4.6 m), and produce 6,000 lbs (2.7 metric tons) annually. Their best varieties are Shenandoah, Allegheny, Susquehanna and PA Golden, and grafting onto wild rootstock has given them better drought tolerance. They have tips on commercial-scale pruning, thinning and fertilizing.

Onward and Upward

I was thrilled to learn that the zebra swallowtail butterfly has a single host – the pawpaw! We have these butterflies (in small numbers) and I didn’t know much about them. The caterpillars do not do significant damage to the leaves of grown trees, and the acetogenins from the leaves make the insect unpalatable to predators.

I have one little quibble with this book, which is that it would have benefited from tighter editing in some places. It’s not at all verbose or convoluted, but sometimes a piece of info has become detached from its colleagues, and occasionally it gets repeated. But all the info here is good, and actionable. And if you don’t read the whole book at one sitting, as I did, it won’t even be a problem!

After you’ve enjoyed the book, if you are anywhere nearby, book in for one of their open days between March and June, and in September and October at Long Creek Homestead near Frederick, Maryland. The annual Pawpaw Festival is in September. No! No! don’t just show up at their home at some random time of your choosing! See their website www.ecologiadesign.com

The Judds’ round house. Long Creek Homestead 
Photo Michael Judd

 

Dragonfly Swarms, Mother Earth News, and Heritage Harvest Festival

Dragonfly photo courtesy Staunton News Leader

Swarms of dragonflies are popping up  in Virginia

Leanna Smith, in the Staunton News Leader reported that meteorologists in Ohio had spotted something unexpected on the radar on September 10 — a swarm of migrating dragonflies. The radar maps are impressive! The Common Green Darner dragonflies (Anax junius) were reported swarming in Maryland (Sep 11 evening), New Jersey (Sep 12 nighttime) and Virginia (Sep 11 and Sep 12 morning).

She reported that it is common for dragonflies, especially green darner dragonflies, to migrate south in the fall to find warmer weather, but the swarming is unusual. Ohio State University Entomology Professor Norman Johnson spoke to CNN and said that weather conditions can cause the traveling insects to swarm. In 2018, the Washington Post reported that the migration of green darner is typically unremarkable because the insects rarely travel in packs. Although much is still unknown about the migration of dragonflies, we do know that they are very sensitive to temperature. “Climate warming could really disrupt the presence of this migration,” Colin Studds, an animal ecologist at the University of Maryland Baltimore County, told the Post.

It is fairly common for radar to pick up biological movement, especially around sunrise and sunset when warmer air above us can bend the radar beam toward lower elevations where the movement is occurring, according to meteorologist Chris Michaels.

On September 10, the National Weather Service of Cleveland, Ohio tweeted about the new development.

Clouds of dragonflies.
Photo NWS Cleveland @NWSCLE

Ohio State University entomologist Norman Johnson said the dragonflies are likely Green Darners, which migrate south in the fall. “The insects don’t usually travel in flocks,” he told CNN, “but local weather conditions can cause them to bunch up.” “The big swarms have been recorded a lot over the years, but they’re not regular,” Johnson said.

Details of dragonfly migration are still unclear; researchers have found the winged creatures travel an average of 8 miles per day, but can fly as far as 86 miles.

For up to the minute sightings, see the Migratory Dragonfly Partnership Search page

TOWARD THE UNKNOWN  A common green darner can migrate hundreds of kilometers each year. A new study reveals details of the insects’ annual migration for the first time. Photo Mark Chappell

Susan Milius in Science News reports that Green Darner dragonflies migrate a bit like monarch butterflies, with each annual migratory loop taking multiple generations to complete.

Ecologist Michael Hallworth and colleagues wrote the migration of the common green darner, described December 19, 2018 in Biology Letters, using data on forms of hydrogen in the insects’ wings, plus records of first arrivals spotted by citizen scientists. Citation https://doi.org/10.6084/m9.figshare.c.4320911.v2

“A first generation of insects emerges in the southern United States, Mexico and the Caribbean from about February to May and migrates north. Some of those Green Darners reach New England and the upper Midwest as early as March, says Hallworth, of the Smithsonian Migratory Bird Center headquartered in Washington, DC.

Those spring migrant darners lay eggs in ponds and other quiet waters in the north and eventually die in the region. This second generation migrates south from about July until late October, though they have never seen where they’re heading. Some of these darners fly south in the same year their parents arrived and some the next year, after overwintering as nymphs.

A third generation emerges around November and lives entirely in the south during winter. It’s their offspring that start the cycle again by swarming northward as temperatures warm in the spring. With a wingspan as wide as a hand, they devote their whole lives to flying hundreds of kilometers to repeat a journey their great-grandparents made.

Tracking devices that let researchers record animals’ movements for more than a week or two haven’t been miniaturized enough to help. The smallest still weigh about 0.3 grams, which would just about double a darner’s weight, Hallworth says. So researchers turned to chemical clues in darner tissues. Conservation biologist and study coauthor Kent McFarland succeeded at the delicate diplomacy of persuading museums to break off a pinhead-sized wing tip fragment from specimens spanning 140 years.

Researchers checked 800 museum and live-caught specimens for the proportion of a rare heavy form of hydrogen that occurs naturally. Dragonfly wings pick up their particular mix of hydrogen forms from the water where the aquatic youngsters grow up. Scientists have noticed that a form called hydrogen-2 grows rarer along a gradient from south to north in North America. Looking at a particular wing in the analysis, “I can’t give you a zip code” for a darner, Hallworth says. But he can tell the native southerners from Yankees.

An adult darner, regardless of where it was born, is “a green piece of lightning,” says McFarland, of the Vermont Center for Ecostudies in White River Junction. Darners maneuver fast enough to snap insect prey out of the air around ponds across North America. The front of an adult’s large head is “all eye,” he says, and trying to catch samples for the study was “like hitting a knuckleball.”

Although the darners’ north-south migration story is similar to that of monarch butterflies (Danaus plexippus), there are differences, says evolutionary biologist Hugh Dingle of the University of California, Davis, who has long studied Monarchs, which move northward in the spring in successive generations, instead of one generation sweeping all the way north.

Also, Dingle says, pockets of monarchs can buck the overall scheme. Research suggests that some of the monarchs in the upper Midwest do a whole round trip migration in a single generation. As researchers discover more details about green darners, he predicts, the current basic migration scheme will turn out to have its quirky exceptions, too.”

MASS MIGRATION

At least three generations make up the annual migration of common green darner dragonflies. The first generation emerges in the southern United States, Mexico and the Caribbean starting around February and flies north. There, those insects lay eggs and die, giving rise to second generation that migrates south until late October. (Some in that second generation don’t fly south until the next year, after overwintering as nymphs.) A third generation, hatched in the south, overwinters there before laying eggs that will start the entire process over again. These maps show the emergence origins of adult insects (gray is zero; red is many) captured at sampling locations (black dots).

Diagram by Matthew Dodder, M.T. Hallworth et al/Biology Letters 2018

Geek.com reports that this isn’t the first insect invasion of 2019. In June, the National Weather Service’s radar in San Diego picked up a giant crush of ladybugs about 80 miles across in each direction, over southern California. On June 27, residents of northeastern Ohio found themselves dealing with invasive mayflies, which covered cars, houses, and lampposts across Cleveland, Sandusky, and other areas.

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Mother Earth News Fair

I had a great time at the Mother Earth News Fair at Seven Springs, Pennsylvania. My first workshop, Lettuce Year Round, was on Friday lunchtime and attendees were still arriving. For those who wanted to hear all about it, but missed it, here is the slideshow:

And here is the extended version of Hoophouse Cool Season Crops. It has a lot of bonus material compared to the short workshop I gave last weekend.

Note that all the offers of pdfs of my books to download are scams and nothing to do with me! I cannot stop people posting them. It’s almost enough to stop me posting my slideshows, but I know people appreciate another chance to see the slides.

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Heritage Harvest Festival

This coming weekend, Saturday September 21, I’ll be presenting Winter Gardening: No Tech to High Tech with Ira Wallace at the Heritage Harvest Festival at Monticello in Charlottesville, VA. Ira will talk about outdoor winter gardening, and I’ll talk about hoophouse growing (which isn’t really that high tech!) It’s Saturday, Sept. 21 at 10:30am in the Heritage Tent. Here’s the LINK. The workshop is for gardeners to learn tips on growing cold-hardy vegetables (and not just kale!) out in the open and with varying degrees of protection from rowcovers, low tunnels, coldframes and hoophouses.

Read more about the Heritage Harvest Festival here

Buy tickets in advance here

Weeding rowcovered spinach in winter.
Photo Wren Vile

September in the hoophouse: sowing spinach, replacing bubble foil insulation, removing shadecloth

Two jars of sprouted spinach seeds and grits to prevent the damp seeds clumping.
Photo Pam Dawling

Sowing Spinach

We sow our first hoophouse spinach in the ground around September 7. Because it’s too hot in the hoophouse at this time for spinach seed to germinate, we pre-sprout the seed for a week in the fridge before sowing. This is very easy, much easier than growing beansprouts!

We measure out the amount of seed we’ll need and soak it overnight in a jar of water. We use 1oz (28 g) of seed per 90ft (27.4 m) row. We use a cup measure or a tablespoon that we keep in the spinach seed bucket. 7T = ½ cup. 1T=15 ml. It’s very roughly ½ cup per row. We use Mason jars and replace the flat metal lid with a piece of screen of some kind, metal or plastic, with holes smaller than spinach seeds. The Mason jar lid band holds this in place.

In the morning we drain off the excess water, and set the jar in the fridge on its side. Once a day we rotate the jar to even out the moisture and therefore hopefully the rate of growth of the shoots. After about a week the seeds have grown a short white root 1/8” (3 mm) long and are ready to sow.

Spinach seedlings from pre-sprouted seed in the hoophouse in September.
Photo Pam Dawling

When there is extra moisture with the seeds they can tend to clump together. One solution to this problem is to mix in a dry inert material like corn grits, as in the first photo, to make the seeds easier to sow individually. This year I tried a different approach. I spread out a scrap of rowcover on the ground and spread the seeds out on that to dry the surfaces. This made the seeds easy to sow, but I noticed that several white rootlets were left behind on the rowcover. I don’t know if the rowcover Velcro effect caused this or if it was a higher rate of damage than the grits treatment. It wasn’t a significant amount.

Replacing bubble foil

Beyond time to replace this torn and crumbling bubble foil insulation.
Photo Pam Dawling

We have a 3 ft (1 m) length of a foil and bubble-plastic roll material along the base of the north wall in our hoophouse. The north side is the coldest, and not a lot of direct light comes in there, that low down, so we decided to insulate from radiation losses and also get some light reflection back there. I think it works well, although I have not measured anything to see if my impressions are backed up by reality! We put the hoophouse up in 2003 and we have replaced this “bubble foil” once since. Definitely we left it too long since we last changed it. As well as big rips, we had micro-crumbs of plastic flaking off. Not what we want in our food!!

An office staple remover is the perfect tool for removing the batten tape (old driptape).
Photo Pam Dawling

I pulled off the old stuff, using an office staple remover to extract the old staples. I reused the scrap driptape we had been using as batten tape (still years of life left for it in that role!) My approach to agricultural plastics is to buy the most durable and treat them gently to make them last as long as possible. We had two partial rolls of the bubble foil material in the shed, so I used those, but found myself 14 ft (4 m) short, so we had to buy some more. I don’t know about durability, but the Reflectix product was the sturdiest at the start. How long would this stuff normally last? Two changes in 2003-2019 = 16 years. 8 years is too long! 6 or 7 seems like it might be OK. Ask me in 2025!

A quick crop of Tokyo bekana Asian greens for salad, in front of the new bubble foil.
Photo Pam Dawling

Removing the shadecloth

The 15 year-old shadecloth on our hoophouse is still serving us every summer.
Photo Pam Dawling

In the summer we cover our hoophouse with a large sheet of shadecloth. We pack it away in the second week of September. (It helps if the first bed of winter crops (planted September 6-7) has had a chance to germinate before we make it hotter in there by pulling off the shadecloth.) Our shadecloth is 50% knitted polyethylene. I think 45% would be better than 50%, next time we buy. And I think buying 100 ft (30 m) would be better than just the 96 ft (29 m) length of the hoophouse. See the way the shadecloth pulls away from the ends in the photo.

Our hoophouse in 2008 when the shadecloth was in better condition.
Photo Pam Dawling

We are still using the shadecloth we bought in 2004, 15 years later. It has a few mouse holes that happened in storage, and the fabric is starting to lose its strength and rip. We used to fix  snap-on grommets to the center-line of the shadecloth at the ends and tie with ropes onto the end wall structure. But nowadays the shadecloth is too weak to withstand the firm pull we need to give to get those ends in place. So we get a hot spot at each end of the hoophouse. We’ll need to buy new shadecloth in the next couple of years. Probably we can cut the old piece up into 7 ft (2 m) strips to use over beds of lettuce outdoors. It won’t need much tensile strength for that task.

We use snap-on grommets, big hooks in the baseboard and a long piece of rope, to hold the shadecloth along each long side of the hoophouse.
Photo Pam Dawling

Cooking Greens in September

Fall-grown senposai.
Photo Pam Dawling

Cooking Greens to Harvest in Central Virginia in September

Chard and senposai are available here all month (and longer).

Some of the unusual warm weather cooking greens, such as Malabar Spinach, sweet potato vine tips, okra leaves, molokhia (Egyptian spinach, related to okra), manihot (aibika) are still edible in early September. See the July and August posts for more about those.

Yukina savoy, komatsuna, Maruba Santoh, pak choy, Tokyo Bekana and Chinese cabbage, can be available throughout September, if they were sown in late June or early July.

At last it is the season here for delicious new cooking greens! Broccoli (from 9/10), cauliflower (from 9/15), beet greens (from 9/20), cabbage (from 9/25), turnip greens (from 9/25), and collards from late September.

We may still have spring cabbage in the cooler, if we had a good harvest.

Cooking Greens to Sow in Central Virginia in September

September is a busy month for sowing greens outdoors. We want the crops to be established before cold weather, so they can make growth throughout the winter whenever it’s warm enough (anything above 40F (4.4C) is warm enough for kale, spinach and lettuce to grow a bit.).

Young tatsoi plants in our early hoophouse bed September 25.
Photo Pam Dawling

We also prepare and plant our first hoophouse bed. That post is  an excerpt from The Year-Round Hoophouse © Pam Dawling and New Society Publishers.

Here’s our day-by-day schedule for both outdoors and our hoophouse:
  • September 6: Direct sow in the hoophouse: spinach #1, tatsoi, Bulls Blood beets
  • September 7: Last date for first round of kale sowings outdoors.
  • By September 15: Sow outdoors if not done yet: kohlrabi, kale and collards; Hoop and net.
  • Early-mid September: Sow spinach #1 outdoors (pre-sprouted). We have trialed various spinach varieties for our hoophouse and for outdoors, and our current favorites are Reflect (outdoors) and Acadia (both outdoors and in the hoophouse).
  • September 15: our first round of nursery sowings for the hoophouse: pak choy, Chinese cabbage, Yukina Savoy, Tokyo bekana, chard, (as well as lettuce and frilly mustards for salad mixes). Two or three times in September we sow crops in an outdoor bed to be bare-root transplanted at about 3 weeks old into newly prepared hoophouse beds. This gives the warm weather hoophouse crops (including cover crops) longer to grow, and also gives the seeds cooler conditions to germinate in. Because the pest pressure outdoors is fierce at that time of year, we hoop and net these very important plants. Our rough formula for all transplanted fall brassicas is to sow around a foot (30 cm) of seed row for every 12’–15’ (3.6–4.6 m) of crop row, aiming for three seeds per inch (about 1 cm apart).
  • September 15 is our last date for resowing kale outdoors, if we are to get any winter harvests from it.
  • Mid-September: Sow spinach in the coldframes. In spring we will use the coldframes to harden off seedlings, but over the winter they make a nice sheltered space to grow more spinach. We will cover the coldframes in the middle of winter. An advantage of using the coldframes for spinach is that the area around the frames is all mulched, and accessible regardless of the weather.
  • By mid-September: Sow turnips outdoors, hoop and net them.
  • September 20-30: Sow spinach #2 outdoors for spring harvest. The goal here is to provide a succession of spinach harvests. This later sowing will size up in early spring and give good harvests before the newly transplanted spring spinach, and be better quality and more abundant than the beds sown in early September.
  • September 24: nursery sowings #2 for the hoophouse: we first -resow any failed #1 sowings; and also sow Red Russian kale, White Russian kale, senposai, Yukina Savoy, Frilly Mustards, and more lettuce. We hoop and net.
  • Late September: Sow Eat-All Greens See the Special Topic for September below.
  • September 30: As needed we resow any of the hoophouse transplants that we are short of.

Cooking Greens to Transplant in Central Virginia in September

An outdoor bed of young Vates kale Photo Kathryn Simmons

In early September, we transplant collards and kale if we didn’t finish in August.

We only grow Vates kale, a very cold-hardy dwarf Scotch curled type outdoors. When the kale is about 3-4 weeks old, we use plants from any of the beds to fill out any other (if we have enough spare plants). We resow if the survival rate is really poor. We eat any extra plants.

In late September, we finish the kale gap-filling. From then on, what we see is what we’ll get.

Other Cooking Greens Tasks in Central Virginia in September

Weed and thin kale to 12”

To improve spinach seed germination we have put spinach seeds in the freezer in mid-August or earlier (at least two weeks). We reclaim it from the freezer and let the waterproof container warn up to ambient temperatures before opening it. Otherwise condensation will land on the seeds and ruin them for future sowings.

Young spinach seedlings.
Photo Pam Dawling

To presprout spinach, measure the required amount of seed, put it in a jar and cover with water overnight. Fit a mesh screen lid (a piece of window screen held on a Mason jar by the metal band works well, although you can buy longer-lasting metal or plastic mesh lids too. In the morning, strain off the water, turn the jar on its side, shake out the seeds to lie along the side of the jar, and lay the jar in the fridge. Once a day, give the jar a quarter turn to shuffle the seeds and even out the moisture. You are not growing bean sprouts, and you do not need to rinse and drain the spinach seeds. After 6 or 7 days, the seeds will have sprouted enough to plant by hand. Perhaps spread the seeds to dry for an hour on a tray or a cloth. If the seeds stick together as you start to plant, mix in a little dry, inert, absorbent material like uncooked corn grits, bran or oatmeal (but not sticky bread flour).

Beet seeds can also be presprouted, but a bit more care is needed, as it is easy to drown beet seeds. Soak them in water for only an hour or two, and do not use much more water than needed. I realize that’s a tall order the first time you do this, as you won’t know how much is too much! Err on the side of caution! Don’t let the sprouts grow very long, as they are brittle. A short red sprout is all you need.

Special Cooking Greens Topic for September: Eat-All Greens

I introduced the topic of Virginian Eat-All Greens in my blog in November 2015.

Young rows of September-sown Eat-All Greens in early October.
Photo Bridget Aleshire

Carol Deppe, in her delightful book The Tao of Vegetable Gardening explained the concept and the practice of growing Eat-All Greens. Carol grows these by broadcasting seed of one of her carefully chosen greens crops in a small patch. When it reaches 12″ tall, she cuts the top 9″ off for cooking, leaving the tough-stemmed lower part, perhaps for a second cut, or to return to the soil. I wanted to try this idea in Virginia, where the climate is fairly different from the Pacific Northwest where Carol lives. I decided fall was a promising time of year to try this scheme, and we sowed some on September 16 that year. We hadn’t planned ahead, and didn’t have the perfect range of seeds (see The Tao of Vegetable Gardening for that). We experimented with seeds we had on hand or could get quickly, and we sowed in rows rather than broadcast, because we knew we had a lot of weed seeds in the soil.

Carol Deppe has an article on How to Easily Grow High-Yielding Greens in Mother Earth News Feb/March 2016, which you can read about here

A section of Eat-All Greens in October.
Photo Bridget Aleshire

We harvested in October and for the third time on 11/3, and several more times. By December 22, I was noting “Our Eat-All Greens are still alive, if not exactly thriving. The peas have been harvested to death; the kohlrabi, beets and chards are never going to amount to anything; some of the more tender Asian mustard greens are showing some frost damage. On 12/10 we made one last crew foray to harvest – not greens, but roots!” We harvested two and half buckets of radishes and 5 gallons of turnips before the end of the year. I’m not sure how many harvests of cooking greens we’d had, but it felt plentiful..

Some Eat-All Greens in early November.
Photo Lori Katz

On January 12 I noted: “We had a low temperature of 6F on January 5th. Not much [of the Eat-All Greens patch] is left alive. Always enthusiastic to keep updating my list of cold-hardy winter vegetable crops, I took my notebook and walked the rows a few days later.”

I wrote up our Eat-All Greens for Growing for Market magazine and you can read it in the January 2016 issue. We thoroughly enjoyed the experiment, and the sight of all those rows of abundant greens in the late fall and early winter.

Frosty Mizuna in our Eat-All Greens in December.
Photo Bridget Aleshire

Hear Chris Smith In Defense of Okra at Heritage Harvest Festival

Chris Smith, author of The Whole Okra

I’m a big fan of Chris Smith and his work. I reviewed his book The Whole Okra on this site and I want to tell you that you can hear him speak at the Heritage Harvest Festival.

His talk In Defense of Okra is on Friday, Sep. 20th: 1:30 3 pm at the lovely Woodland Pavilion. Click here to buy tickets.

Go if you love okra. Go if you hate it – you might change your mind!

The workshop description says:

Calling all worshippers of this much-maligned, tasty vegetable (that is technically a fruit). And okra doubters beware — we’re about to change … your … life.

Join Smith, author of the newly released book The Whole Okra: A Seed to Stem Celebration, for an interactive and entertaining exploration of the culinary (and non-culinary) uses of okra. Having grown 125 varieties, Smith will share and sample many of the incredible uses of the plant, including okra kimchi, pickled and fermented okra, okra flower tea, okra-seed coffee and okra oil — not to mention the world-renowned delicacy, okra marshmallows.

Participants will learn to enjoy (yes, even LOVE) and appreciate this disparaged underdog — from pod to stem. Take home delicious recipes that will have you profusely apologizing for ever uttering the word “slimy” in its presence.

The future of okra rests on your shoulders. Do the right thing.

Cow Horn okra flower and pod.
Photo Pam Dawling

Author of The Whole Okra, expert okra enthusiast Chris Smith writes regularly for The Heirloom Gardener, the Mother Earth News blog, and the Farmers’ Almanac blog. His presentations on the versatility of okra have delighted audiences at food and farming festivals and fairs throughout the Southeast. He is the Executive Director for The Utopian Seed Project, Communications Manager for Sow True Seed in Asheville, North Carolina, and serves on the board of The People’s Seed. A native of the UK, Smith has a master’s degree in creative writing from the University of Manchester. His short stories have been published in Nashville Review, Mid-American Review, and The Manchester Review.

Yes, he’s a fellow Brit. He’s very funny. He’s very knowledgeable about seeds and growing vegetables.

Monticello hosts the annual Heritage Harvest Festival

Get Info on Other Workshops here

Get Tickets here

Potato Research, Mother Earth News Fair PA and Heritage Harvest Festival

Crates of potatoes in our root cellar.
Photo Nina Gentle

Potato Research on Harvest and Storage

Last week I mentioned that while researching potato yield figures, I found an interesting publication, The Potato Association of America, Commercial Potato Production in North America 2010. I’ve been reading that and learning more about potatoes. Here I’m going to focus on harvest and storage, because that’s the bit we’re currently challenged by. I also learned more about planting in hot weather, but that’s for another time.

Potato harvest.
Photo Nina Gentle

In England we planted in spring and harvested in October, waiting for the frost to kill the vines. In Virginia we plant in March and June, harvesting in July and October. We have grown Red Pontiac, Yukon Gold and Kennebec here, mostly. They all seem to be determinate varieties. I only just learned there are determinate (varieties with naturally self-limiting growth, generally “early” varieties) and indeterminate varieties (such as “Russet Nugget,” “Nicola,” “German Butterball” and “Elba”). The distinction is explained in Potato Bag Gardening. Growers using towers, grow bags, and cage systems want indeterminate potatoes, which continue to produce more layers of tubers on the stems as they are progressively covered with more soil. Growers wanting a fast reliable crop in the field mostly choose determinate types, which grow as a bush, then flower and die. The Wild Woolly Web does seem to have some contradictory statements about which varieties are determinate and which indeterminate, and some dedicated container growers make assertions not supported by experienced commercial growers. So Reader Beware! I trust Extension and here’s a link to their Ask an Expert page on potato types, and the University of Maryland Extension Home and Garden Info Center Potatoes.

June-planted potatoes in early September
Photo Kathryn Simmons

Whether the vines die naturally at the end of their lifespan, or they die of disease, or the frost kills them, or you kill them yourself by mowing or flaming, the potatoes will store better if you then wait 2-3 weeks before harvesting. The potato skins thicken up (becoming more resistant to scrapes and bruises) and the potatoes become higher in dry matter. Harvesting is easier if the vines are well dead. We generally bush-hog ours. Decades ago, in England, we had late blight in the middle of the season, and we cut the tops off and made a very smoky bonfire. (I wouldn’t participate in that much air pollution nowadays!) After waiting for a couple of weeks for the late blight spores to die, we dug the potatoes. The idea was to prevent spores getting on the tubers. As I remember, it all worked out OK.

If at all possible, harvest when the soil moisture is 60-80% of field capacity. Not too dry, not too wet. This reduces damage from scraping. If using a digger, don’t set it digging too deep, or too much soil will be damped on the harvested potatoes.

Tuber temperature will also impact bruise and rot susceptibility. Ideally soil temperature will be 45-65F (7-18C).  Because soil temperature lags 3-4 hours behind air temperature rise each day, in cold weather, try to harvest around 6 pm or a bit later. In hot weather, harvest in the morning.

When freshly harvested, potatoes are tender, breathing things. Avoid bruising, which is damage that does not break the skin, by not dropping potatoes more than 6” (15 cm), or throwing them towards a container. Don’t bang them to knock off extra soil.

When harvesting in summer, we stack the crates of potatoes under a big tree overnight to lose some of the field heat before moving them to the root cellar early next morning. Potatoes you take from storage can be no better than the quality of the potatoes you put into storage!

The first part of the storage period is the curing. The potatoes are still actively respiring, so they need a good oxygen supply. Failure to ventilate the cellar enough can lead to Black-heart, where the inner tissue of the potatoes dies and turns black. During the curing period, the skins further toughen up, and cut surfaces and superficial wounds heal over, enabling long term storage. The temperature should be as close to 50-58F (10-14.4C) as you can get. The lower end of the range is best for fresh eating (as opposed to junk food manufacture). Hotter temperatures will promote more rot, and age the potatoes faster, leading to early sprouting. Relative humidity should be 90%, but not 100%! If there is too much condensation, use a fan and open the cellar doors, when temperatures are closest to the goal. Curing takes 10-14 days.

Sorting potatoes .
Photo Wren Vile

We find that a single thorough sorting after 14 days can remove almost all of the storage problems that are going to happen. Not sorting at this point lets rots spread.

After the curing period, the potatoes become more dormant and do not respire so actively. They don’t need as many air changes as during curing, but if the cellar is too warm, you will need to aerate more. The temperature during the storage period should be 40-50F (4.4-10C), and closer to the lower end of the range is best. Constant temperatures or a steady decline is the goal, not dramatic fluctuations. Humidity should still be 90-95%, to keep weight loss to a minimum.

Potatoes have a natural dormancy of 60-130 days (depending on the storage temperature). After that period, they will start to sprout. Some plant extracts, including clove oil, can add 20-30 days storage, and will then need to be reapplied. I do not know anything about this myself, and do wonder how you remove the clove flavor from the potatoes!

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Speaking Events

I have two speaking events coming up in September
Mother Earth News Fair

2019 Mother Earth News Fair Pennsylvania.

September Friday 13- Sunday 15, 2019
Location: Seven Springs Mountain Resort, 777 Waterwheel Dr., Seven Springs, Pa. 15622

I am giving two 60 min workshops

Hoophouse winter lettuce: Green Forest, and Red Salad Bowl, two of our fifteen varieties.
Photo Wren Vile

Lettuce Year-Round on Friday 9/13 12.30-1.30 pm at the Grit Stage

This presentation includes techniques to extend the lettuce season using row covers, cold frames, and hoop houses to provide lettuce harvests in every month of the year. The workshop includes a look at varieties for spring, summer, fall, and winter. Pam Dawling considers the pros and cons of head lettuce, leaf lettuce, baby lettuce mix, and the newer multileaf types. She also provides information on scheduling and growing conditions, including how to persuade lettuce to germinate when it’s too hot.

Cool Season Hoophouse Crops on Saturday 9/14 3.30-4.30 pm at the Building and Energy Stage

Learn how to fill your hoop house with productive food crops in the cool seasons. Pam Dawling discusses suitable crops, cold-hardiness, selecting crops, calculating how much to harvest and how much to plant, crop rotation, mapping, scheduling, seasonal transitions, succession planting, interplanting, and follow-on cropping.

Book-signing at the Bookstore Saturday 4.30-5 pm. Buy new books at the Bookstore and bring your grubby used copies to be signed too!

Demos at New Society Publishers booth, of tomato string-weaving and wigglewire system for fastening hoophouse plastic to framework
Friday 3 -3.30 pm, 4.30-5 pm; Saturday 10-11 am, 1.30-2.30 pm; Sunday 9-10 am. 1-2 pm, 3.30-4 pm

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Heritage Harvest Festival, Monticello, Charlottesville, VA

September Friday and Saturday 21-22, 2019
Buy tickets online
Workshop with Ira Wallace
10:30 – 11:30 am Saturday in the Heritage Tent

Winter Gardening: No Tech to High Tech 

Learn tips on growing cold-hardy vegetables (not only kale!) out in the open and with varying degrees of protection from rowcovers, low tunnels, coldframes and hoophouses (high tunnels). We’ll consider crop choices, planting dates and harvesting so there’s always something to eat for everyone from winter market gardeners to small backyard growers. We’ll explain ways to maximize production with succession planting and follow-on cropping.

 No extra fee for the workshop, included with the price of general admission

Booksigning: SATURDAY, SEPT. 21st, 11:45am – 12:15pm, MONTICELLO SHOP TENT (WEST LAWN). Buy new books at the Bookstore and bring your grubby used copies to be signed too!

December view in our hoophouse, showing lettuce mix and turnips.
Photo Wren Vile

Ice for lettuce seed; Mistake in my book; fall sowings

Ice cubes over newly sown lettuce seed, to help germination in hot weather.
Photo Bell Oaks

The photo above shows our strategy for germinating lettuce seed when the soil is too hot (above about 84F (29C). First I shade the soil for several days to cool it, and I keep it moist. Then I sow late in the day, cover the seeds with soil, tamp down, water with fresh-drawn cold water, set out ice cubes along the rows, cover with shadecloth and retire for a relaxing cup of tea. One tray of ice cubes is enough for a 4ft (1.2 m) row.

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I just got this email pointing out a mistake in Sustainable Market Farming. So get a red pen and fix your copy today! An observant reader said:

“Hi! I just read the section on potatoes in your book “Sustainable Market Farming” and was a bit confused because of the yield numbers on page 376. You write “Yields are likely to be 150 lbs/ac (168 kg/ha); 200 lbs/ac (224 kg/ha) is a good yield”.

I’m currently working on a farm where we get 200-250kg of potatoes from one 100m row, that’s the number you say is a good yield per hectare… And I don’t even think our yield is particularly good, because there was a lot of damage in the potatoes (green ones, wireworm, slugs, scab). So I guess your numbers are just a mistake?”

Yes, my mistake indeed! On page 45, I have the (better!) info that potatoes can yield at least 110 pounds/100 feet, or 49.9 kg/30m. I think I probably meant to write on page 376, that a low yield could be 150 pounds/100ft, which is equivalent to 11 tons/acre. In the metric system, that’s 223 kg/100m, or 24.4 tons/ha. Other sources suggest average yields could be almost twice this. And good yields, even 4 times the low numbers.

So it should say

“Yields are likely to be 11 tons/ac (24.4 tons/ha); 22 tons/ac (48.8 tons/ha) is a good yield”

That’s US tons of 2000 pounds, metric tons of 1000 kg. Or for a smaller scale, probably closer to what most of us are growing,

“Yields are likely to be 150 lbs/100ft (223 kg/100m); 200 lbs/100 ft (300 kg/100m) is a good yield”

I hope I’ve got all the conversions right. Let me know if I haven’t!

While researching yield figures, I found an interesting publication, The Potato Association of America, Commercial Potato Production in North America 2010.

Potato harvesting

The month of August is when we establish crops that will feed us in the fall and winter.

We sowed carrots August 8 and are now hoeing them and hand-weeding and thinning. We flamed these carrots on day 4 after sowing, because we have found that carrots can emerge on day 5 when it is as warm it can be in August. The idea is to flame the beds the day before the carrots are due to emerge. Flame-weeding is a great way to get rid of millions of fast-growing weeds and leave the field free for the slow-growing carrots. We still have to weed and thin once or twice as the carrots (and weeds) grow, but it is much easier to see the carrots, and they grow better if the first flush of weeds has been flamed off.

Some years all goes smoothly, and some years not! This year we had two snags. One is that the carrots were mistakenly sowed an inch deep, instead of near the surface. Of course, this delays emergence, so by the time the carrots made it through that inch of soil, many new weeds had sprung up too. The second challenge was that our well pump has not been working right, and we have not had enough irrigation water. And until this past week, we had a very hot dry spell.

Looking forward to lush beds of fall carrots.
Photo Bridget Aleshire

But now we are making forward progress. Twin Oaks can eat 30+ bags (50 lbs, 23 kg each) of carrots during the winter, so we try really hard to grow a big crop of fall carrots.

We sowed cucumbers 8/2 and they are up well. The 8/5 beans look very good indeed.

Young bean bed.
Photo Pam Dawling

The first two beds of kale (sowed 8/8) came up well, thanks to diligent hand-watering. The second two (8/12) are also up, and it’s just a day too soon to say the third (8/17) are just as good. Sowing two beds of kale at a time is a good strategy allowing us to focus the hand watering on the not-yet-emerged beds, for best success. We try to have the pairs of beds very near each other, to make dragging the hoses easier. This year we even sowed some back-up flats of kale, because last year’s kale had such a hard time getting established. (It might have been cutworms or grasshoppers).

Young Vates kale.
Photo Bridget Aleshire

The squash was sown a little late this year (8/10 rather than 8/5) but there is still hope. Our average first frost is 10/20 (our average over the last 13 years), so with a 54 days to maturity (from direct seeding) squash like Zephyr, we reckon on sowing 68 days before that first frost – or more to allow for seasonal cooling and even an early frost. That’s 8/13 absolute last date. We’ll use rowcover once fall cools down, but we do hope for a decent yield before the plants get killed.

Our fall turnips are doing well. We sowed them 8/7 under insect netting. here you see a row of radishes squeezed in at the edge of the bed. We often do this with radishes because we only want 90ft (27 m) at once. Kale beds are another place we sometimes sow radishes. Because radishes grow so fast, they will be gone by the time the slower, bigger crops need the space. And because they don’t get tall, they can be at the edge of the beds without getting in our way as we walk along.

Young turnips with a row of radishes squeezed into the bed.
Photo Kathryn Simmons