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 toCNN and said that weather conditions can cause the traveling insects to swarm. In 2018, theWashington 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 meteorologistChris Michaels.
On September 10, the National Weather Service of Cleveland, Ohio tweeted about the new development.
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.
“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 Darnersreach 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.”
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.
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:
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.
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.
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.
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
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!!
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!
Removing the shadecloth
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.
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.
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 Julyand August posts for more about those.
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.).
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.
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
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.
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
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.
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..
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.
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.
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.
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.
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.
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.
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!
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.
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
Heritage Harvest Festival, Monticello, Charlottesville, VA
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!
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.
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!
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.
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.
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).
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.
Solarization is a method of killing pests, diseases and weed seeds near the surface of the soil by covering the soil with clear plastic for six weeks or more in hot weather. We use this method to help control nematodes in our hoophouse. Nematodes are only active in warm weather, and we have not had problems with them outdoors, but of course, it’s warmer in the hoophouse!
I’ve written before about solarization to fight nematodes in our hoophouse.
“Solarization uses clear plastic (old hoophouse plastic is ideal). In a summer hoophouse, solarization can be as quick as 24 hours, Andrew says. When we’ve done this, one of our goals was to kill nematodes and fungal diseases, not just weeds, so we waited a few weeks. Outdoors it takes several weeks. You can see when the weeds are dead. Bryan O’Hara poked a thermometer probe through solarization plastic and found a 50F degree (28C) difference between the outside air and the soil immediately under the plastic; a 10F (6C) difference at 1″ (2.5 cm) deep and little temperature gain lower than that. Solarization does not kill all the soil life!”
In June this year I wrote about using marigolds, sesame, Iron and Clay cowpeas as nematode resistant cover crops. We’ve also used winter wheat, and white lupins. See Our Organic Integrated Pest Management . Other cover crops that suppress nematodes include some other OP French marigold varieties (but avoid Tangerine Gem or hybrid marigolds); chrysanthemum; black-eyed Susan; gaillardia (blanket flower, Indian blanket); oats; sesame/millet mix. We decided against sorghum-sudangrass (too big), winter rye (harder than wheat to incorporate by hand), bahiagrass, Bermuda grass (both invasive), castor bean and Crotolaria (sunnhemp) (both poisonous, although newer varieties of Crotolaria have lower toxin levels, and I’ve been rethinking my opposition to using that), partridge pea, California poppy (both require at least one full year of growth) and some obscure vetches that weren’t available locally. We might have included Pacific Gold mustard (B. juncea), if we’d found it in time. Don’t confuse this with Ida Gold Mustard, which kills weeds, and is susceptible to nematodes.
Food Crop Choices
This list starts with the crops most resistant to Root Know Nematodes and ends with the most susceptible. I’ve included some “bookmarks” between categories, but it can also be read as a continuous list:
We came up with a collection of nematode-resistant winter greens, including radishes, Russian kales, Brassica juncea mustards (mostly salad greens like Ruby Streaks, Golden Frills, Scarlet Frills), and Brassica rapa var. japonica greens, mizuna and Yukina Savoy. We have since learned that Yukina Savoy is a Brassica rapa, not B. juncea as we thought, and that mizuna is Brassica rapa var. japonica with a less certain resistance, or perhaps Brassica rapa var. niposinica, or perhaps B.juncea after all (integrifolia type). We also grow scallions in the nematode-infested areas. Now I am looking for more nematode-resistant cold-weather greens.
After the winter greens this spring, we transplanted two beds of tomatoes, one each of peppers, squash and cucumbers, and put two beds into Iron and Clay cowpeas. The eastern ends where we had found evidence of nematodes, we transplanted French marigolds and sesame as stronger fighting forces.
When we pulled up the squash and cucumbers we found no sign of nematodes on the roots. One of the tomato beds produced no sign either, but the other one did. Our first response was to sow Iron and Clay cowpeas instead of the planned soybeans, but before the plants were even 2” (5 cm) high, we decided to solarize that whole bed. We now have small patches of nematode infestation in almost every bed, calling for a more nimble approach to crop planning.
Brassica juncea mustards to try
According to Wikipedia, Brassica juncea cultivars can be divided into four major subgroups: integrifolia, juncea, napiformis, and tsatsai. I did some searching for more B. juncea, especially large leafed ones. Some promising looking crops include these:
Cooking Greens to Harvest in Central Virginia in August
Chard leaves and sweet potato vine tips can be harvested here all month. It really isn’t the season for new cooking greens. We have cabbage in storage, to get us through the “dead center” of the summer, until we can start the fall green harvests. In late August we can start to harvest senposai, turnip thinnings, Yukina savoy, komatsuna, Maruba Santoh,pak choy, Tokyo Bekana. Turnip thinnings can make a tasty dish, if the small plants with marble-sized turnips are cooked together with their attached tops. Wash well, of course.
If we had grown them, we could harvest molokhia (Egyptian spinach, related to okra), manihot (aibika, also related to okra), and okra leaves themselves, if the Japanese beetles have left enough! See the special topic below for more on these.
Cooking Greens to Sow in Central Virginia in August
We sow our fall brassicas weekly throughout late June and July – see the Special Topic for June for all the details. If we have had big trouble, we might need to resow some broccoli, cabbage, or Asian greens in August, but hopefully not. If we do need to resow this late, we choose only the fast maturing varieties, to make up for lost time.
Although sowing the fall greens in nursery seedbeds comes to an end, we are not slacking. August is our month to establish 6 beds of Vates kale. We use ProtekNet against flea beetles. Our method is a hybrid between direct sowing and transplanting. With over 2160 row ft (660m) to establish in the sometimes brutally hot and dry conditions, we would not want to transplant this number of plants. Direct sowing all at once would be impossible for us to keep sufficiently watered. We focus on two neighboring beds (720 row ft, 220m) at one time. We direct sow the two beds, cover with netting, and water by hand every day. In 4 days the seedlings will have emerged, and they can survive on less than daily watering after 6 days. So every 6 days we sow two beds. Our dates are August 4, 10, and 16. Sometimes we sow by hand, sometimes with the EarthWay seeder, with plate 1002-24. Our last date for this round of sowings is September 7.
On August 20 we revisit the first two beds and resow if the survival rate is really poor, or we plan to move plants around to fill gaps, if there are not too many. On August 24 we revisit the second two beds and resow sections if needed. On August 28 we revisit the last pair of beds sown. Our last date for resows is September 15. We only grow one variety outdoors, and we can use plants from any of the beds to fill out any other. We tackle this task when the plants are about 3-4 weeks old, in late August and early September. We eat the extra plants.
We grow Vates kale, a very cold-hardy dwarf Scotch curled type. I’d love to find a bigger equally-hardy curled variety, but I have not found any. We don’t rowcover our outdoor kale, so it needs to be very hardy. We tried rowcover one year, but it was a bother to deal with, and fibers of the rowcover caught in the curly leaves and we were not appreciated by the cooks.
For the second pair of beds, we often repurpose the first of our brassica seedling beds, as the broccoli, cabbage and Asian greens are all planted by then, the bed has clean soil, and netting and sticks at the ready.
We sow turnips from early August to mid-September, and beets from early August to late August, for both roots and greens. It is hard to get beets germinated in hot soil, but if you delay, they don’t have time to grow big roots before the cold weather. You can sow beets dry or presoak 1-2 hours (not longer, and not in too much water, as they easily drown); sow 1/2″-1″(1-2.5cm) deep, tamp the soil, keep the surface damp, water daily for the 4-6 days they take to emerge. We use netting for turnips, but not for beets, unless the grasshoppers are bad.
It’s also possible in warmer areas to sow Swiss chard or leaf beet for a fall crop. This is a useful Plan B if some other crops have failed. The last planting date is ten weeks before frost. Our average first frost here is October 20. This is an average over the past 13 years. We can only sow chard until August 11 or so. It’s not that the first frost will kill the chard, far from it, but the frost date is an indicator of when growth starts to slow down.
Cooking Greens to Transplant in Central Virginia in August
June is the time to prepare a plot for the fall broccoli and cabbage. July and August are the time for transplanting them. See the July cooking greens post for details of how we tackle this big transplanting job. In early August (if not done in late July) we transplant two beds of collards. By late August we want to really finish transplanting the fall broccoli, cabbage, and the kale from the August 4 sowing.
In week 7 of our fall greens schedule (the first week of August): We transplant week 4 sowings of senposai, Yukina Savoy, and anything we resowed in week 4. We also fill any gaps in week 4 transplantings (= week 1 sowings). Cover: hoop and net or rowcover.
In weeks 8 & 9 (the second and third weeks of August): We transplant anything we didn’t keep up with, and replacements in weeks 5 and 6 transplantings (weeks 2 & 3 sowings), Cover: hoop and net or rowcover.
Other Cooking Greens Tasks in Central Virginia in August
If things are on schedule and we haven’t needed to replace many casualties in the big brassica patch, we roll and store the covers, wheelhoe or till between the rows and weed. Then we undersow with a broadcast mix of mammoth red clover, white Ladino clover, and crimson clover. This will become our all-year green fallow next year.
August is our worst month for grasshoppers and crickets, so we watch for them and either use netting, or postpone sowings until the end of August.
To improve germination next month, we put spinach seeds in the freezer now, for at least two weeks.
No visible brassicas month comes to an end. To disrupt the lifecycle of the voracious harlequin bugs, we have only netted brassicas in our gardens from early July, when the last of our spring brassica crops get mowed down and disked in, and we sow seedling brassica crops under netting. When we transplant the young brassicas, we cover those all with netting or rowcover for a few weeks.
Special Cooking Greens Topic for August: More Unusual Hot Weather Cooking Greens
See Cooking Greens in Julyfor details about the chenopods – amaranths, Aztec spinach, orach, Good King Henry, Magenta Lambsquarters, strawberry beet and also celosia. Many of these can be sown again in August to provide a succession of tender young greens. Here are some other hot weather greens. Like July’s unusual cooking greens, all the following are warm weather crops, so don’t try to grow these in early spring or into late fall. If sown in August, they can follow an earlier crop such as lettuce, peas, or early sowings of beans, squash or cucumbers.
Sweet Potato Leaves, Ipomoea batatas
Plant sweet potatoes for a fall root harvest, and get the bonus greens crop all summer! You can harvest the leaves and young shoots for cooking greens at any time during growth (just don’t take too much at once). For cooking ideas, find Water Spinach recipes and substitute sweet potato shoots. Chili and shrimp or peanut sauce feature in many recipes.
Water Spinach, Ipomoea aquatica; aka Kang Kong, Ong Choy, Phak Bung.
This tropical, semi-aquatic plant is cultivated for its tender shoots and leaves. It is easy to start from seed or you can root cuttings (roots show in 2-3 days) from bunches bought at an Asian supermarket. The long stems will readily root from the nodes. The leaves are quite large: 2”-6” by 1”-3” (5-15 by 2.5-7.5 cm). The tender shoots are cooked along with the leaves. The flowers look just like sweet potato flowers. It is a USDA Class A noxious weed in Hawai’i, Florida and California, where it has escaped into the wild. Check your state regulations, and grow this in some sort of container to be sure. A safer bet is to eat sweet potato greens instead.
New Zealand Spinach (Tetragonia expansa, Tetragonia tetragonioides)
New Zealand Spinach tolerates heat and drought beautifully. It is salt-tolerant and will even grow in sand. This sprawling bushy plant with small, succulent, triangular leaves is generally free of pests. The flavor is very mild, not particularly like spinach, despite the name.
Soak the seed for 4-24 hours before planting to speed germination – it can take 8 weeks to emerge. Direct-sow from mid to late spring (bean-planting time), or sow indoors about 6 weeks before last frost. It takes 65-75 days to maturity. Thin to at least 6” (15 cm) apart. It needs hot weather to really get going.
Regular trimming encourages lush growth. Use scissors to harvest the shoot tips. Picking the individual triangular leaves would be tedious, as they are fairly small.
Like true spinach, Tetragonia leaves contain oxalic acid, so should be eaten in moderation, mixed with other greens.
It can become invasive as it sets seed readily. This happened to me the first year I grew it – I thought some self-sowing would be a good thing, but I seriously under-estimated both the number of seedlings I’d get and the distance the seeds could ping.
Malabar Spinach (Basella alba, Basella rubra)
This tropical plant is from Asia and Africa.. The gorgeous twining vines are very tall, so they need to be trellised or caged, which has the bonus of keeping the leaves clean. One technique is to plant them on the pea trellises and let them take over as the peas finish. There is a green-leaved Malabar spinach with red stems, but the red is exceptionally beautiful, so I recommend that one. This crop also does well in partial shade.
The crinkled heart-shaped leaves look like spinach, although more crisp, glossy, and slightly succulent. They have a flavor similar to beet greens. They stay mild and maintain healthy growth all summer. Bees love the blossoms.
Sow in late spring, when it’s warm enough for beans. Germination is slow – even at their preferred temperature of 70-80°F (21-27°C) the seeds can take 10-14 days. Soaking the seed in warm water before sowing may help. You could start them indoors and transplant at 3-6 weeks old, or older, as much as 8” (20 cm) tall. Plant or thin to at least 6” (15 cm) apart and, to promote a more branched plant, pinch out the central shoot after the second set of leaves.
The plants need 60-90 days to maturity, and then will produce an abundance of moderately small leaves all summer, until cut down by the slightest frost. Harvest individual leaves as needed, or cut the vine tips to use as cooking greens. (Young leaves can be added to salad mixes.) Lop the vines when they are as tall as you want to deal with – they will regrow even if severely cut back.
The taste is slightly seaweedy (it’s also known as “land kelp”), and the texture is somewhat mucilaginous in the way that okra is. It can be eaten raw if you like the chewy texture. It is excellent for stir-fries or for thickening summer soups and stews. William Woys Weaver reports that it cooks beautifully in a microwave, but on a hot day eat the refreshing leaves raw. The leaves store for up to two weeks in the refrigerator.
This crop is pest-free, but watch out for the staining properties of the black berries (good for dying fabric). Malabar spinach does self-sow, but this is only likely to be a problem for those in tropical climates
Yes, okra leaves are edible. See Chris Smith’s amazing book The Whole Okra
Egyptian Spinach, Corchorus olitorius (Jute, related to okra)
Aka Melo Khiya, Molokheiya, Molokhia and similar attempts to render the Arabic name in our alphabet. This Arabic summer cooking green grows well in Virginia, North Carolina, Florida, Texas and everywhere with hot summers.
This versatile, continuous-harvest vegetable can survive both dry and wet conditions in warm or hot weather.GrowerJimhas good details.
Only the small leaves are cooked and eaten. The dried leaves can be used to thicken soups or for tea. It’s not a vegetable to be eaten alone in big cooked heaps – it’s just too mucilaginous.
Jute fiber is extracted from the mature plants, suggesting a) don’t try to eat over-mature plants, and b) paper-making and various fiber arts could be in your future.
Depending on your climate and preferences, you can direct sow fairly heavily and thin, or start seeds in flats and transplant 12″ (30 cm) apart in all directions. Plant after danger of frost is past and the soil is warming steadily. Egyptian Spinach likes full sun, warm to hot weather and steady moisture – mulch will help keep the soil moist.
It takes 70 days to maturity, then holds well in the field, providing several cuttings. If you prefer to harvest the whole plant, succession-sow for future supplies. Continue to give compost or nutrients throughout the season, to encourage tender new growth.
It grows 2’-3′ (60-90 cm) tall or more, and then bears yellow flowers if you don’t keep it clipped back. The flowers are followed by seed pods which are edible and tasty when young, with more flavor than the leaves.
The mature seeds can be saved for replanting. Seed is available from Sandhill Preservationand Bountiful Gardens (who reassure buyers that the seed is naturally green in color and is not treated.)
Manihot (aibika, Sunset hibiscus, also related to okra) Abelmoschus manihot – (L.)Medik.
It is a hardy perennial in US zones 8-11. Green Harvest has growing information. Plants for a Future also. Seeds are sold by Monticello as an ornamental, but Floral Encounters say: “However the importance of this plant is that it is one of the world’s most nutritious leafy vegetables because of its high protein content.”
Squash leaves and shoots, Cucurbita spp.
If your squash are being too rambunctious, or you are thinning a row a bit late and have sizeable plants, consider a harvest of vine tips and leaves. Or grow some just for this purpose, if you need a quick-growing summer green with novelty appeal. Stir-fry or gently braise – good with eggs for breakfast, says Ira Wallace at Southern Exposure Seed Exchange.
Blackeye peas and other crowder peas:
The tips and leaves are edible. Garden Betty writes about many of these less usual greens, from a salad perspective, in Summer-Lovin’ Salad Greens
In April I did a pleasant phone interview with Harold Thornbro of the Modern Homesteading Podcast about how year round gardening in a hoophouse can increase yields and the quality of vegetables and extend the growing season.
The rest of this post is about the agricultural things I’ve changed my mind on in recent years.
The first one that comes to mind is where and how to sow leeks. In Sustainable Market Farming I describe sowing leeks in outdoor nursery seedbeds. We grow leeks for eating from October to March, so even though leeks grow very slowly and need 12 weeks to transplant size, we don’t need to sow them super early in the year. Also because they are so cold-hardy, they don’t need greenhouse conditions. To save greenhouse space, and the bother of watering so many flats, we took to sowing them outdoors. To make this work, you do need weed-free beds. Leeks compete poorly with weeds. Sometimes things went wrong. One year someone decided to “seed-bomb” the fresh bed with poppy seeds. Weeding those tiny leek seedlings was torture! Another time, an overenthusiastic worker ran our new exciting wheel hoe too far onto the bed and eradicated part of a row.
One year the leek seedling bed wasn’t ready in time to sow, and we sowed rows of seeds in a coldframe, after removing the winter spinach (or maybe we were still growing lettuce in the coldframes then.) This worked well. The next year we tried sowing the seeds in 4” (10cm) deep flats, and putting the flats into the coldframes right away (rather than germinating them in the greenhouse). Still no wasted greenhouse space! On very cold nights, we cover the coldframes, so it was a bit warmer than if we’d just sowed directly into an outdoor bed. The plants grew a bit quicker and we realized we didn’t need to start so early. They were easier to take to the field in the flats, compared to digging up the starts and carrying them in little buckets with water. We had reduced losses of seedlings, so we reduced the amount of seed sown in future years. It’s an easier system, with a more satisfying success rate.
Sunnhemp as a Cover Crop
Sunnhemp (Crotalaria juncea) is a warm weather leguminous cover crop that I’ve been admiring at various farms in the Southeast in recent years. I’ve been thinking it would be valuable ion our hoophouse and in our gardens. It fights root knot nematodes! I mentioned it recently at a crew meeting, only to be reminded that I previously spoke against growing it as the seed is poisonous! I’d completely forgotten my earlier opinion!
This summer cover crop can grow to 6’ (2m) in 60 days. It thrives in heat, tolerates drought, fixes nitrogen, suppresses nematodes, makes deep roots that pull nutrients from deep in the soil, and it dies with frost. It sounds fantastic, I really want to try it! It looks a bit like small sunflowers, and according to Southern Exposure Seed Exchange it won’t make mature seed above 28 degrees N latitude , so won’t become a self-sowing invasive in Virginia. Sow in rows 2’-3’ (0.6-1m) apart. If it gets too big, mow when plants reach 5’-8’ (1.5-2.5m) to prevent the stalks from becoming tough and hard to deal with. ¼ lb sows 250 sq ft. (¼ lb = 114 g, 250 sq ft = 23.2m2)
Sowing Sweet Corn
I mentioned earlier here, that I’ve changed my mind about the necessity to put up ropes over corn seed rows to keep the crows off. I suppose there are fewer crows these days, sigh. Not needing the ropes makes the benefits of sowing with the seeder greater than the benefits of sowing by hand, so long as we can irrigate sufficiently to get the seed germinated. When we sowed by hand we watered the furrows generously, which meant we did not need to water again until after the seedlings emerged. If we hit a serious drought, the old method could still be best. Overhead watering does germinate lots of weeds, including in the wide spaces between the corn rows, so we need to factor in the extra hoeing or tilling when we weigh up the pros and cons. So, I’m a “situational convert” on this question!
How to Kill Striped Cucumber Beetles
I wrote about these beasties here. We handpick the beetles in the hoophouse squash flowers, hoping to deal with the early generation and reduce future numbers. One year we had our first outdoor squash bed very close to the hoophouse and the beetles moved there. In desperation I used Spinosad, an organically approved pesticide. It is a rather general pesticide, and harms bees, so I carefully sprayed late in the day and covered the row with netting to keep bees off. It worked brilliantly, taking a fraction of the time that daily handpicking takes. I became a convert to that method, but no one else on the crew did, so we went back to hand-picking.
I used to maintain that life is too short to prune tomatoes, which grow at a rapid rate in our climate, and get fungal diseases, necessitating sowing succession crops. The past couple of years I have removed lower leaves touching the soil, and this year I reduced the sideshoots on our hoophouse tomatoes, which are grown as an early crop here.(We’re about to pull them up in early August, as the outdoor ones are now providing enough). I do think we got fewer fungal diseases, and the diseases started later compared to other years, so I am now convinced that removing the lower leaves is very worthwhile. We also got bigger fruit this year, which logically fits with reducing the foliage some amount.
Is There Such a Thing as Too Much Compost?
I used to think the more compost the better. Now I am more aware that compost adds to the phosphorus level in the soil. I wrote about that here. I am not as alarmist as some people about high P in our situation, but I do now think it is worth paying attention and not letting the levels build too fast. I have got more enthusiastic about growing cover crops at every opportunity, and finding legumes to include in cover crop mixtures at every time of year (see above about sunnhemp). I was already a cover crop enthusiast, but as my experience increased, I got my mind round more possibilities.
In my youth I was anti-plastic, If I were growing food just to feed myself, I’d probably still find ways to avoid almost all plastics, but growing on a commercial/professional scale (and getting older) has led me to appreciate plastics. I still don’t want to do plastic mulch, except the biodegradable kind, but I’ve come to accept durable light weight plastics for their benefits. Drip tape saves do much water, reduces weed growth. Plastic pots and flats are so much easier to lift! I do still pay attention and try to make plastics last a long time, and frequently salvage plastic containers others discard. I’m awed by the possibilities of silage tarps or old advertising banners, to keep down weeds without tilling and pre-germinate weed seeds so that when the covers are removed, few weeds grow. This was called by the awkward name of “occultation”, but is now more often referred to in English as tarping.
Lastly, I have a post on Mother Earth News Organic Gardening about hornworms, but you read it here first!
200 pages, color photos and drawings throughout, $24.95
We all need to read more books like this, to prepare for climate chaos and global heating. Alone, we can’t control how much it rains, or when, but we can improve our farming so that rain penetrates deep into the soil, is stored there and is able to keep plants and livestock alive through dry times. The author farms and ranches cattle in Kansas, using less than 4 acre inches of rain per year. This book is mostly addressed to livestock farmers, not vegetable growers like me. I skimmed some sections, although not much, as the same principles of caring for the soil apply to all farmers. This book is not about Organic Farming. Selective use of herbicides is advocated. But you decide. Selectively graze this book, taking only what you like!
[Oh why are books on sustainable agriculture in the US printed in China?]
The first part of the book is about creating a water-efficient soil with three approaches: getting more water into the soil; keeping water in the soil for longer; and helping plants get more of that water. The second part of the book is about providing for livestock: ensuring a reliable water supply; creating drought-tolerant pastures; providing emergency forage in a drought; and livestock decisions after a drought.
Part 3 of this very practical book is Looking to the Future, and includes water-efficient agriculture for semi-arid regions. There are resources for further reading, metric conversion charts and a glossary, and of course an index (without which no practical book is actually practical!) Buy this book to get the checklist of actions to take to prepare for future droughts, and cope with them as they occur.Ken Burns’ documentary The Dust Bowl should be required viewing, says Dale Strickler. We need to learn from history. Dale learned as a young man that the fantastic corn yields in Iowa were not due to that state having more rain than Kansas, but to the better soils. He also learned it is possible to get better yields on less rain. Poor soils are unable to hold onto the rain they do get. And this is something we can do something about. Dale increased his soil’s ability to hold water from 3” in 18” depth to 12” in the much-improved 6 ft depth after 11 years. Yes it takes time – start yesterday! The three key parts of this feat are:
Get the water in (not running off)
Keep it stored in the soil
Ensure the plant roots can get the water out when they need it.
Getting more water absorbed into the soil depends on creating a good soil structure, with good-sized water-stable aggregates and large-sized pores. Minimizing heavy tillage (think compaction) will help towards this goal, as will increasing the organic matter, using organic mulches, including crop residues (Dale’s excellent example shows the true costs of baling corn stalks for emergency fodder and selling at $60/ton, while incurring costs of $30/ton and losing the fertilizer value of those stalks at $49/ton). After several years of this treatment, yields go down and the soil loses structure. Over-grazing leads to similar results. Bare soils cannot easily absorb water – keep roots in the ground, and preferably some foliage above ground, at all times. Animal manure on the surface also improves water infiltration – the worms and beetles that feed on the manure make burrows that allow water to reach deeper into the soil.
Dale recommends feeding hay in the fields, either unrolled or with bales spaced around the pasture. Uneaten hay and the manure add a lot of organic matter and fertility. Mycorrhizal fungi on plant roots exude glomalin, a stable gluey compound that greatly improves soil structure. The fungi themselves act like root hair extensions, increasing water uptake ability. Earthworms make burrows (air and water conduits) and line them with slime, which helps soil aggregation. Decayed plant root channels also let water deep into the soil. For best results, combine fibrous-rooted cover crops (grasses, buckwheat) with tap-rooted cover crops (brassicas, sweetclovers, sunflowers).
Terracing, or other ways of working on contour help to reduce runoff and make full use of the water that does arrive. Swales, keyline shaping (contour ridges), retention dams in seasonal waterways, all aim to slow down runoff and give more opportunity for water to soak in.
The next step is to bank the water in the soil for longer. We do not want soils that rapidly evaporate all the water, leaving a brickyard. Peat bogs store lots of water, but this isn’t what we need either. How best to manage the water once it is in the soil? Soils lose water in three ways: it gets sucked up by plants, it evaporates from the soil surface, or it leaches down below the root-zone.
Not every drop of water sucked up by plants is helping us – manage or eliminate weeds to leave more for the crops. Preventing a pound of smartweed growth can save 678 pounds of water! Better to grow a pound of crop plants. Overcrowded plants grow taller, but not stronger, as the roots are restricted. Get weeds early, we all know that. If you’ve forgotten why, this book will remind you of the science! In pasture, many weeds are crops, as far as the livestock is concerned. Sometimes rotating different types of livestock will make best use of the plants you have.
As the amount of CO2 increases, plants become more water-efficient. This is because they don’t open their stomata so wide to get enough CO2, and less water transpires out. Increase the CO2 held in the plant canopy by reducing tillage (which instantly flushes out lots). Organic no-till systems allow natural decay and slow release. Keep lots of organic matter on the surface, and if your soil is acidic, add lime.
To reduce evaporation, provide shelterbelts and windbreaks, which cut the wind speed. Research has shown that woody windbreaks increase yields from an area ten times their height. And yet, when times get hard, some farmers pay good money (that will never come back) bulldozing hedgerows to gain a tiny amount of land, with no understanding of the coming decline in yield. Protecting the soil from excessive sun can also reduce evaporation (minimize bare soil). The book has a convincing photo comparing tall healthy corn planted into hairy vetch mulch, with a shorter, curled leaf droughty corn on bare soil.
Dale explains the Law of the Most Limiting Factor, which is helpful to overwhelmed farmers seeing lots of problems. Tackle the factor that is the first to limit the growth of the crop, whether that is sunlight, nitrogen, water or something else.
Organic matter in the soil improves water-holding capacity (both the depth of water penetration and the amount per inch). Increasing soil organic matter comes up next. Anyone over 50 might have been taught that it is not really possible to increase soil OM at a reasonable price. This is not true! By good soil husbandry you can indeed improve soil OM. Conserve crop residues, add cover crops, add manure or compost, reduce tillage and observe the C:N ratio needed for humus production (1 part N: 10 parts C) and don’t forget the sulfur. Some studies seem to show that feeding the crop residues to livestock, letting the manure stay on the fields can increase yields even though the measurable %OM is not higher than if the residues had been left on the field.
The focus then moves on to helping plants get more of the water out of the soil. Improving root depth is key, but sub-soiling is not usually a good way to do this, although Dale concedes that in the Southeast, it can work for one year at a time, perhaps replacing the heavy frost heaving that happens in winter further north. If possible, find other ways to reduce compaction. The more water there is in the pore space, the less oxygen there is. Field tile drainage can help remove excess water, and prevent a low level of oxygen limiting root growth. Earthworms, deep-rooted plants, increased OM, improved aggregation all help increase oxygen flow to the roots. Increase root water-efficiency by ensuring adequate fertility; enlist mycorrhizal fungi by using an inoculant if needed.
I’m considering photocopying the chapter summary pages for a Cheat Sheet on those Practical Strategies. As I said, I skimmed the livestock farming details, but the information on the impact of drought on livestock farmers and ranchers gave me compassion for those faced with suffering animals. Having to make decisions in a hurry to prevent undue suffering can lead to long term problems for the farm. Sometimes row crops must be sacrificed to provide fodder, when pastures become “crispy brown exercise lots”. Dale has the experience. He tells of neighboring farmers getting together to net all the fish from all their ponds before the ponds dried up. They had a neighborhood fish fry, and he ate fried snapping turtle that day.
Providing surface water includes keeping well-maintained ponds that livestock do not trample down. Dale shows how to provide a livestock “beach” with geotextile and gravel, and old tires forming a fence in the water. He shows how to set up a siphon to bring water out of a pond; how to set a living willow hedge to protect steam banks and pond edges; how to build a shade roof for cattle that catches and provides rainwater; how to build temporary ponds with rubber sheeting and hay bales or earthbags; how to drill a shallow well; and how to enclose a spring to protect it from trampling and provide clean water. Here’s info on addressing water quality issues such as excess nitrates, blue-green algae, salt, and sulfates; and on the use of fish trap gates to encourage livestock to move themselves to the next paddock when they need water.
The next chapter is on creating drought-tolerant pastures. Test the soil, and choose pasture plant species carefully. Here is a good explanation of the three photosynthesis pathways, discovered so far. C3 plants have 3 carbon atoms in the first product of photosynthesis. Cool-season grasses and almost all shrubs, trees and broadleaf plants (think brassicas and legumes) are in this group, which has the poorest water-efficiency, and on hot sunny days can use only about 50% of the available sunlight. The book explains why. While the plants have plenty of water, they can use it to cool the leaves; but if it’s hot and the soil is dry, growth is restricted.
C4 plants include warm-weather grasses (including corn), pigweeds, and lambsquarters. They grow best in hot weather, and are unproductive in cold weather. While they are more water-efficient, they are less digestible and low in protein. It is wise to interseed C3 and C4 grasses, adding appropriate mycorrhizal fungi for the C4 grasses, to speed up establishment and provide better long-term productivity. Add deep-rooting plants (chicory or alfalfa).
The third photosynthetic pathway mentioned is the Crassulacean Acid Metabolism (CAM) pathway, and it has by far the best drought tolerance. This pathway is found in succulents such as yuccas, cacti, pineapples. They close their stomata during the day, having stored CO2 for photosynthesis. These otherwise promising-sounding plants grow very slowly. They may have a place as drought rations, once the spines have been burned off, or the whole plants have been ground to a “soup”.
Calculating and maintaining a sustainable stocking rate will prevent the downward spiral that comes from overgrazing. Stock conservatively such that only 40% of the foliage is removed in the worst years. There are no financial savings from overgrazing. Removal of more than 40% of the leaf area results in a loss of root growth, hindering recovery. You make more money from conservative grazing than from exploitative grazing. The book has the research to prove it. Consult your local NRCS, who can calculate a suitable stocking rate (free of charge). In wet winters, it is often better to make a woodchip mulched winter feeding lot with spaced hay bales, than let the soil get “pugged”.
There is technical information here about growth stages of different grasses – it’s most important to avoid too much defoliation of cool-season grasses in late spring; warm-season grasses benefit from a rest in late summer. Plants with growing points near the ground can survive close grazing better than those with elevated growing points.
Chapter 7 delves into providing emergency forage in a drought, as an alternative to reducing stocking levels and thus reducing income (hard for any farmer to do). Hopefully, using the previous info, your pastures will be improved and more drought-resilient, and you are less likely to face this emergency. If you do, the first place to look is failed rowcrops, which you can graze or cut and haul (grazing is better). Beware the urge to make silage, as it loses 20% of the feed value in fermentation. And it’s heavy to haul. Also, it leaves your fields denuded, unless you immediately sow a cover crop, which is tricky in a drought. Strip grazing using electric fencing is a better way to go, and also lets you force a better balanced diet of grain and stalks on your livestock, reducing the risks of acidosis, excess nitrates or prussic acid poisoning from young sorghum growth.
Another source of emergency rations is crop residues, such as corn stalks, strip grazed as for failed crops. It is important to understand the nutritional limitations of what you are feeding. There are feed additives used by some ranchers to increase the digestibility of some feedstocks.
Winter cover crops are another emergency feedstock in desperate winters. Tree branches, or felled trees, can save the season occasionally (obviously not every year). Plan ahead and cut poles of cottonwood or willow (whichever grows locally) and plant your own emergency feedlot. It can serve as shade and shelter in non-drought years until needed. Possibly thinning the trees the first time round could actually improve the health of the spared trees.
Another approach is to cut hay on areas that would otherwise get mowed, such as roadsides or parks or serve wetland plants, weeds, lawn clippings, dormant grasses (those bison weren’t wrong!). If you can supplement the protein with legume hay or oilseed meals, do that. For low protein feeds such as dormant grasses, choose mature, non-lactating animals. Planning ahead, it makes sense to shift the birthing season to the beginning of the high-quality grazing season.
There are various (sometimes painful) livestock decisions to make during droughts and in the aftermath. Dale recommends making a written plan, which will save revisiting the decisions each day, and will reduce the stress of making decisions in the thick of it. Deciding to reduce the herd size is easier if you have some animals that you find easier to let go of. Having such “stocker animals” that you intend to sell at some point reduces the decision to when to sell. Having some pre-set trigger dates when decisions need to be made will help you ease into it. Set an initial date to decide the stocking rate for the season, and another when half the growth of the grass will have occurred, for both your cool season and your warm season pastures.
Another strategy is to have some of your livestock be able to survive in buildings or dirt yards for a while. Far from ideal, but in a drought, we are already far from ideal, and climate chaos is going to throw us into situations we have never seen before. Make a priority list of which animals must be first to go when a reduction is needed.
When you’ve done all the things mentioned, and you still have animals to feed, look thoughtfully at hay, silage and grain. It is better to start feeding some hay while the pastures are still in good shape than to overgraze and then have only hay. You want your pasture to respond quickly as soon as rains do arrive, to regrow and be stored for winter. Have a sacrifice lot or pen, where you feed hay, and keep the animals off the pasture, so it can recover sooner. Or graze for a few hours, then feed hay in the lot.
Whatever else you do, keep notes of your observations, your actions, the results and anything you think would have been better. This will position you for better results next time.
The last part of the book looks to the future. The cautionary tale of how the Dust Bowl was created by poor farming practices is relevant to all of us. The lessons are: Farm to suit the land, the climate and the plant species already growing; don’t believe theories (“Rain follows the plow”, “Use dust mulch”, “Deeply tilled soils will catch more rain”) disseminated by people living far away, or companies that are set to gain from farmers following their advice; don’t move hundreds of miles and expect to farm the same way you did “back home”; check the research for results you can depend on, think it through for yourself, and watch what is working for farmers around you, before trying something really different.
Reading about how the Plains are suited to grazing is instructional for anyone who thinks animals should be eliminated from agriculture. Living in central Virginia, I am not in a place to make an informed judgement, but Dale Strickler is. He has a system of capturing falling rain in grasses or cover crops, converting 40% into meat or milk (by grazing, which adds manure to the soil) and leaving 60% to cover the soil. In drought years, maintaining a flexible mind, using those decision-point dates to make best choices for the current year, having some “flex-pastures”, considering all your options rather than panicking, are going to help.