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

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

Modern Homesteading Interview, Things I’ve Changed My Mind On

Hoophouse squash, tomatoes, and cucumbers.
Photo Alexis Yamashito

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.

You can listen to it here:

https://www.stitcher.com/podcast/modern-homesteading-podcast/e/60326060?autoplay=true

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The rest of this post is about the agricultural things I’ve changed my mind on in recent years.

Sowing Leeks
Leek seedlings growing in an outdoor nursery bed.
Photo Kathryn Simmons

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.

Leek seedlings in flats in April.
Photo Pam Dawling

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 cover crop at Nourishing Acres Farm, NC.
Photo Pam Dawling

 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
Young sweet corn with a sprinkler for overhead watering.
Photo Bridget Aleshire

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
Striped cucumber beetle in squash flower.
Photo Pam Dawling

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.

Pruning Tomatoes
Hoophouse tomatoes in early May
Photo Bridget Aleshire

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?
Too much compost?? A commercial compost windrow turner.
Photo by Pam Dawling

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.

Using Plastics
Rolling biodegradable plastic mulch by hand
Photo Wren Vile

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.

Hornworms

Lastly, I have a post on Mother Earth News Organic Gardening about hornworms, but you read it here first!

Hoophouse Squash Variety Trial, Garlic Recap, Flowers for Organic IPM

Golden Glory Squash in our hoophouse in mid-June.
Photo Pam Dawling

Hoophouse Squash Variety Trial

A month ago I wrote about our hoophouse squash variety trials for pollination issues and blossom end rot. I think our problem was mostly unpollinated squash, rather than blossom end rot. Go to last month’s post for valuable links to distinguish the two conditions.

We planted 15 Golden Glory zucchini (good at setting fruit without pollinators) along with 25 Gentry yellow squash (a favorite variety, except that we had pollination troubles with it in our hoophouse for several years). The trial is almost over, we’re about to pull those plants, and we have plenty of squash coming in from our outdoor plantings now. The first outdoor planting includes some Golden Glory too, so if I have more news I write about it when it happens.

Gentry yellow squash in our hoophouse in mid-June
photo Pam Dawling

As I said last time, I recorded the number of small rotting squash we removed. The Golden Glory produced far fewer rotten unpollinated fruit.

Date 15 Golden Glory plants: rotted fruit Golden Glory: rotted fruit per plant 25 Gentry plants:

rotted fruit

Gentry:

rotted fruit per plant

5/13 2 0.13 12 0.48
5/14 2 0.13 5 0.2
5/17 0 0 32 1.28
5/21 15 1 54 2.16
5/27 9 0.6 39 1.56
6/4 13 0.9 29 1.2
6/10 2 0.13 11 0.46
6/14 2 0.13 9 0.43
Average per plant   0.38   0.97

 But low numbers of rotted fruits is not the only goal! Yield is important too, and the healthiness of the plants (which relates to yield).

We noticed that the plants were starting to die, and we thought of bacterial wilt. But when I tried the test for that disease, the results were negative. The test is to cut through the plant stem, rub the cut ends together, then slowly separate them. If the plant has bacterial wilt, there will be bacterial slime in strings between the stem ends when you slowly draw them apart. We got nothing like that. More research needed!

We pulled the dying squash, put them in a black trash bag and set that in the sun to cook.

Diseased squash, mid-June.
Photo Pam Dawling

Here’s what we found:

Date 15 Golden Glory plants: Number of healthy plants Golden Glory: Percentage of plants healthy 25 Gentry plants:

Number of healthy plants

Gentry:

Percentage of plants healthy

6/4 15 100% 25 100%
6/10 15 100% 24 96%
6/14 15 100% 21 84%
6/18 10 67% 20 80%
6/24 6 40% 18 72%

Initially, the Gentry started to keel over, then suddenly the Golden Glorys weren’t so glorious!

As far as yield, we did not measure it much. We only have notes from one day, 6/10. We harvested 7 squash from 15 Golden Glory plants (47%) and 14 Gentry from 24 plants (60%). Different people harvested on different days, meaning sometimes they were picked bigger than on other days. My sense is that the Golden Glory were not as productive throughout their harvest period. They are beautiful, the plants are open, easier to harvest from, and we had fewer rotten squash, and initially fewer dying plants. Is this enough to recommend them for an early hoophouse crop in future years?

My inclination is to also try another variety that is rated well for setting fruit without pollinators (hence fewer tiny rotting squash) and try harder to also record yield as well as problems next year!

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Garlic Recap

Our garlic is at the “Trim and Sort” stage, but depending where you garden, yours may be at a completely different stage. See my blogposts from the previous year, when I posted my Alliums for the Month Series.

Trimming garlic stems.
Photo by Brittany Lewis

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For people in colder climates than Virginia, you may be just starting to harvest your garlic. Learn from Margaret Roach (who grows in Massachusetts) in A Way to Garden

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Here are a couple of allium resources that didn’t make it into the Alliums for the Month Series

Mulching alliums

The Nordells on mulching alliums

RAMPS

Barry Glick sells ramps

“The Cat Is Out Of The Bag”!!!
Sunshine Farm & Gardens
696 Glicks Road
Renick WV 24966 USA

Ramps plants.
Photo Sunshine Farm and Gardens

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Flowers for Organic IPM

This is my post on the Mother Earth News Organic Gardening Blog

Organic Integrated Pest Management involves tackling pest problems one step at a time with ecologically-based practices, starting with reducing the chances of the pest ever getting a grip on your crops. Follow prevention with avoidance, and finish with pest-killing if needed. I recommend the ATTRA online publication Organic Integrated Pest Management. Each  page is a poster, complete with good photos and concise clear info.

In May we transplant flowers in our vegetable garden to attract pollinators and pest predators. We like a combination of sunflowers, dill, borage, cosmos, calendula, tithonia (Mexican sunflowers), zinnias. See my earlier Mother Earth News post Insectaries: Grow Flowers to Attract Beneficial Insects

We sow sunflowers about every 10ft (3 m) in each of our bean beds. We are growing sesame surrounded by French marigolds in our hoophouse to deter nematodes, which we have in parts of our hoophouse soil. Sesame is apparently particularly good in deterring root knot nematodes, the type we have.

French marigolds and sesame to deter Root Knot nematodes in our hoophouse.
Photo Pam Dawling

Our Organic Integrated Pest Management

French Marigolds and sesame to combat root knot nematodes in our hoophouse.
Photo Pam Dawling

Organic Integrated Pest Management involves tackling pest problems one step at a time with ecologically-based practices, starting with actions chosen to reduce the chances of the pest ever getting a grip on your crops.

Steps:

  1. Cultivate a good environment for your crops: healthy soil, sufficient space, nutrients and water, suitable temperature, soil pH. Practice crop rotation to reduce the chances of pests and diseases carrying over from one crop to the next. Clear old crops promptly, so they don’t act as a breeding ground for the pest. Choose suitable varieties that resist the pests you most expect.
  2. Cover or protect the plants physically from the pests (mulches to stop soil-dwelling pests moving up into your crops, netting, rowcover, planting diverse crops, and even trap crops)
Young cucumber plant under insect netting in June.
Photo Pam Dawling
  1. Provide habitat for natural enemies and other beneficial insects
  2. Monitor crops regularly at least once a week and identify any pests you see.
  3. Introduce natural enemies of the pest (bacteria, fungi, insect predators or parasites)
  4. Hand pick (or trap) and kill the pests if the pest population is above the action threshold. Many fruit and root crop plants can take 30% defoliation before any loss of yield. Where the crop is the foliage, this may be too much!
  5. Use biological controls (often derived from natural enemies) if the damage is still economically significant after trying the earlier steps in the process.

I recommend the ATTRA online publication Organic Integrated Pest Management.

Each of the 22 pages is a poster, complete with good photos and concise clear info.

Our motion sensor sprinkler and the outer layer of our fence around the sweet potato patch at the end of May. The inner fence was installed later.
Photo Pam Dawling

One of our biggest garden pests is the deer, which are especially fond of sweet potatoes. We use motion-sensor water sprayers initially or in years when the deer pressure is low. For worse years we install an electric fence with a solar-powered charger.  Last year our electric fence didn’t keep the deer out, so this year we have a double layered fence to make sure.

Broccoli bed with alyssum to attract aphid predators.
Photo Pam Dawling

At the other end of the size scale are aphids.  We plant sweet alyssum in our beds of broccoli and cabbage to attract insects that will eat aphids. We sow about 200 plugs for 1500 row feet (450 m) of brassicas planted as two rows in a bed, and pop one alyssum plug in the bed centers every  4ft of bed or about one alyssum per  4 plants. We transplant these the same day that we replace any casualty broccoli and cabbage plants.

Nasturtiums planted in with squash to deter pests. Does it work?
Photo Pam Dawling

We transplant some bush nasturtiums in with our first plantings of cucumber and summer squash. They are said to repel some cucurbit pests such as squash bugs., but I can’t vouch for that. Radishes in cucumber or squash rows are said to repel cucumber beetles and squash bugs. I haven’t tried that. There are a lot of companion planting ideas out there, but most have no scientific evidence for effectiveness.

An insectary circle in early June. The flowers will attract beneficial insects.
Photo Pam Dawling

In late May or early June, we transplant some flowers in our garden to attract pollinators and pest predators. We use circles cut from plastic buckets to surround these clusters of flowers so that inexperienced helpers don’t pull them out as weeds.  We use a combination of sunflowers, dill, borage, cosmos, calendula, tithonia (Mexican sunflowers), zinnias.

Sunflower bee and bug.
Photo by Bridget Aleshire

We also sow sunflowers in our bean beds at each succession. These attract birds and pollinators, while also acting as landmarks for our harvest progress.

In our hoophouse we have been tackling nematodes for several years. This year we have planted the nematode areas in French marigolds and sesame (apparently particularly good in deterring root knot nematodes, the type we have.) Some other nematode areas have been planted with Iron and Clay cowpeas. Unfortunately we now have an aphid infestation on the cowpeas! We are trying blasting the aphids off the plants with a strong stream of water from a hose. Later in the summer we will solarize some of the nematode areas.

We planted Iron and Clay cowpeas to deter nematodes, but got aphids!
Photo Pam Dawling
Flowering sesame in our hoophouse, surrounded by French marigolds. We hope they will fight the root knot nematodes.
Photo Pam Dawling

Squash variety trial for pollination issues and blossom end rot

Golden Glory zucchini in our hoophouse in late May.
Photo Pam Dawling

I wrote about our problems last year with unpollinated squash and our decision to try squash varieties that were less dependent on pollination. So this year we planted some Golden Glory zucchini along with Gentry yellow squash that we had troubles with for several years. The trial is not over, but the early results are promising.

We planted 15 Golden Glory and 25 Gentry and I recorded the number of small rotting squash we removed on 5 dates so far.

Gentry yellow squash in our hoophouse in late May.
Photo Pam Dawling
Date 15 Golden Glory rotted fruit Per plant 25 Gentry rotted fruit Per plant
5/13 2 0.13 12 0.48
5/14 2 0.13 5 0.2
5/17 0 0 32 1.28
5/21 15 1 54 2.16
5/27 9 0.6 39 1.56

The unscientific parts of this trial are

  • we are also removing rotten fruits on other day but not counting them (hey, we’re busy!). But we make sure not to leave rotted squash near the plants and confound the next count.
  • It’s early days still, and we may get different results over the whole of the (short-lived!) hoophouse squash season.
  • Productivity is also important. We won’t be as impressed if we get low yields from the (beautiful) Golden Glories

I’ll keep you posted.Later I learned  that summer squash can get blossom end rot, and wondered if we had that problem rather than a pollination issue.

Is this an unpollinated squash or one with Blossom End Rot? It is shrunken, so I suspect poor pollination.
Photo Pam Dawling

See this excellent article Why Are My Squash Rotting? by Charlotte Glen. Here are some of the points she makes:

  • Blossom end rot is not a disease, but a physiological disorder caused by a shortage of calcium. Many factors can slow the absorption or movement of calcium in the plant, leaving it prone to blossom end rot.
  • Depending on what is stopping calcium from reaching the developing fruits, blossom end rot can be temporary or persistent.
  • Low soil calcium levels are rarely a cause of blossom end rot.
  • Blossom end rot is most usually caused by acidic soil (low pH). In soils with pH below 5.5, nutrients (including calcium) can get chemically locked up and unavailable to the plants (even if abundant in the soil). If low soil pH is the cause of blossom end rot, the problem usually lasts the whole growing season.
  • Too much high-nitrogen fertilizer can also cause blossom end rot. Fast-growing plants often cannot move enough calcium into fruits to support healthy development.
  • Stressors such as unusually cool or hot weather, low nighttime temperatures, drought, or over-wet soil can also trigger BER.
  • Any conditions that cause root damage can lead to poor nutrient absorption and blossom end rot. The most common causes of root damage are wet soils following heavy rain or over-irrigation.
  • Another leading cause of blossom end rot is drought – roots cannot absorb nutrients from dry soil, they need a film of water to convey them.
  • To prevent blossom end rot, the most important thing you can do is to keep the soil evenly moist.
Rotting unpollinated squash. Or some other problem?
Photo Pam Dawling

Here’s how I think our squash stacks up on those factors:

  • Our soil pH and our soil calcium level are both fine, we test the soil every year.
  • Home-made compost is our only source of nutrients in our hoophouse apart from occasional cowpea cover crops. I don’t think we overdid the nitrogen this way.
  • Yes, cool night-time temperatures when we first planted the squash in early April could have been a factor then, but now it’s reliably warm and the problem persists (at least with the Gentry)
  • Root damage? We did transplant these, but carefully. Maybe.
  • Uneven irrigation? We try to run the irrigation every day once it warms up. I don’t think that’s the issue. I don’t think we over-irrigated.
Healthy Gentry squash plants in our hoophouse.
Photo Pam Dawling

Then to help my deliberations, I found this
Squash and Cucurbit Problem Solver with many photos of fruit disorders (also leaf, root, stem, seedling and insect problems)Choanephora RotChoanephora Cucurbitarum is a soft rot of the blossom end, but rapidly developing grey-black fungal spores. I have seen that other times, but it’s not what we have in our hoophouse.Gray MoldBotrytis cinerea is another fungus that enters through the blossom end, leading to yellowed ends with grey furry mold. Bothe these fungal diseases are soil-borne, so more common in fruits touching the soil.Their photo of Blossom End Rot shows margins, and their description says: “The blossom end of the fruit fails to develop normally, turning black-dark brown and eventually shriveling and becoming hard.”Their description of poor pollination is this: “Fruit fail to expand normally, quickly turning brown at the blossom end and falling off the plant.” I’ve seen them fall off sometimes.For further help distinguishing between poor pollination and blossom end rot, I turned to the Garden Mentors (Robin Haglund).  She has helpful photos of these the two cause of problems, and these pointers:

  • Shriveling is due to poor pollination, not blossom end rot. Poorly pollinated fruits become obvious much sooner than fruits with blossom end rot. The fruits start to shrivel and yellow (harder to spot on yellow squash!)
  • If the squash was well pollinated, but has blossom end rot, it will grow plump with a sturdy stem, but rot at the end.

Poor pollination can be exacerbated if you use daytime overhead irrigation when the  female flowers are open. Squash flowers open flowers early in the day and close by early afternoon (and are open for only one day). Daytime overhead watering can discourage bees , leaving  your flowers unpollinated.So, more study needed! We definitely have been having poor pollination (shriveled rotten-ended squash that drop off.) maybe we have some Blossom End Rot too. I’m going to pay more attention! And eat lots of squash!

Date 15 Golden Glory rotted fruit Per plant 25 Gentry rotted fruit Per plant
5/13 2 0.13 12 0.48
5/14 2 0.13 5 0.2
5/17 0 0 32 1.28
5/21 15 1 54 2.16
5/27 9 0.6 39 1.56

Hoophouse Greens Clearance, Warm Weather Crops Established

April 23 hoophouse view.
Photo Pam Dawling

Our hoophouse is in transition from the winter greens to the early warm weather tender crops. The photo above shows the old lettuce mix we are about to pull up, young tomato plants edged with late spinach, and a row of early snap peas. We usually grow the quick dwarf Sugar Ann, but seed was not available this year so we are growing Sugar Snap – much taller and slower! Usually we snap the peas in three pieces and put them in our salad mix, but I think we will have finished harvesting hoophouse salad mix and moved on to cutting outdoor lettuce heads when these peas are ready. This amount of peas is far too little to be served alone as peas for our hundred people!

Bulls Blood beets with spots cleared to plant tomatoes in mid-March
Photo Pam Dawling

Transition from cool to warm weather crops

  • We flag planting spots every 2’ (60 cm) down the mid-line of the bed – see the photo above.
  • Harvest crops that are too close
  • Dig holes
  • Add a shovelful of compost in the hole
  • Plant the warm weather crop
  • Over the next few weeks, harvest to the south of the new plants, and anything between them that’s too close
  • Over the following few weeks, harvest the rest of the greens between the new plants and then crops to the north.
  • This overlap allows the new crops to take over gradually, and the winter greens to continue harvest in March and April
  • Having hoophouse greens in March and April is very valuable, because the newly planted outdoor crops are not ready to harvest yet, and the overwintered ones are getting sparse.
Golden Frills and Scarlet Frills.
Photo Pam Dawling

We still have some patches of winter greens, such as the Golden Frills and Scarlet Frills mustards above. We grow different types of frilly mustard to add zip to our salad mixes when they are small. Also, the Brassica juncea group  is resistant to Root Knot Nematodes, which we have been dealing with. We just learned that Golden Frills and Scarlet Frills are both more bolt-resistant than the pretty pink-stemmed mizuna (not a juncea mustard) and Ruby Streaks.

We still have some baby lettuce mix in good shape. Here is our fourth sowing:

Our fourth sowing (Feb 15) of lettuce mix.
Photo Pam Dawling

Our salad mixes currently are spinach, pea shoots, lettuce mix and small Frills or a homemade brassica salad mix. We are starting to crave the crunch and juiciness of big lettuces! We have a few still in the hoophouse, the last of the ones we have been harvesting leaves from all winter and spring. Most of those October-transplanted lettuces have bolted now, and have been chopped up to cycle back into the soil.

Pea shoots make a delightful spring salad ingredient.
Photo Pam Dawling

Our warm-weather crops include two beds of tomatoes, one each of peppers, cucumbers and squash. Here are photos I took yesterday. This year we are trying out Golden Glory squash (yellow zucchini), because they are able to set fruit without pollinators, and we have been having lots of trouble with what I believe are unpollinated squash with brown ends failing to develop.

Hoophouse squash: Gentry on the left, Golden Glory on the right. April 23
Photo Pam Dawling

More recently I heard that they may in fact have blossom end rot. I had not known this can affect squash. It has the same cause as the malady in tomatoes: a shortage of calcium reaching the top of the plant. This can be because of a shortage in the soil, or because cold temperatures slow down its transport. Less likely to be a problem in the hoophouse! In fact it is so hot some days that we have already scheduled a date to pull the big shadecloth over the top.

A hoophouse pepper plant on April 23.
Photo Pam Dawling
A Spacemaster cucumber plant on April 23.
Photo Pam Dawling

Spring hoophouse harvests and greenhouse seedlings

Pink stemmed mizuna in our March hoophouse Pam Dawling

Sorry for the delay in posting this. Apparently a driver hit an all-important cable and the whole county is without internet. Rural living can’t be beat!

Here we are in March. Nothing new to harvest outdoors yet, although the garlic scallions are getting close. But the hoophouse is serving us well. Every day we harvest 5 or 10 gallons of salad mix and either some cooking greens, radishes or scallions. The photo above is a new delight: Pink Stemmed Mizuna from Osborne Seeds

We’ve finished the hoophouse turnips, and are now making serious headway on the kale. We grow both Red Russian and White Russian kales.

White Russian kale from Fedco Seeds in our hoophouse in March.
Photo Pam Dawling
Red Russian kale from Southern Exposure Seed Exchange in our hoophouse in March.
Pam Dawling

We use orange flags to denote where to harvest next, as we have a large hoophouse (30 x 96 ft) and many different crops. It is often obvious as we get closer. Here’s three different ways we are harvesting right now:

Baby lettuce mix after and before harvesting.
Photo Pam Dawling

As you can see we harvest baby lettuce mix by cropping it about an inch above the soil. I think this is the third cutting of this patch. I like to make our salad mixes about one third lettuce, one third brassicas of some kind and one third spinach. The brassica mix below is now bolting, so I pulled it up as I harvested. All brassica flowers are edible, and the buds are just like tiny broccoli.

Brassica (mustard) salad mix after and before harvesting.
Photo Pam Dawling

The spinach I’m harvesting today is our third sowing, and we are cutting outer leaves and chopping them into the salad mix.

Spinach after and before harvesting.
Photo Pam Dawling

For those wondering what the silver stuff is: these three crops are all in our narrow north edge bed. We have 24″ (60cm) bubblefoil insulation stapled onto the hipboard. It reflects back both light (in short supply low on the north wall) and heat.

In the greenhouse we have reached Peak Broccoli Flats season. We have 16 flats for our first planting in the coldframe, 16 of the second and four of the (backup plan) third sowing in the greenhouse.

Some of the many flats of broccoli in our greenhouse in mid-March.
Photo Pam Dawling

We use open wood flats for these kinds of hardy seedlings. We sow 4 rows into 12 x 24 x 3″ flats and then spot out into 12 x 24 x 4″ flats (40 plants each) to grow to final transplant size.

Broccoli in an open seed flat, and seedlings spotted into deeper open transplant flats.
Photo Pam Dawling

That’s it for this week! Hope to see some of you tomorrow at the Virginia Festival of the Book! 

My panel is the Land Use and Foodsheds in the Mid-Atlantic,

Thu. March 21, 2:00 PM – 3:30 PM

New Dominion Bookshop

404 E Main St, Charlottesville, VA 22902

Year-Round Hoophouse Vegetables slide show, and the decision between transplanting and direct sowing

I’ve feeding in a flurry of slideshows I’ve been presenting at conferences this winter. You’ll notice a lot of them have a hoophouse theme, although not all. Here’s one from the four hour course I gave at the Virginia Association for Biological Farming conference.

To view the slideshow full screen, click the diagonal arrow icon. You can then hop, skip and jump through it, choosing the bits you are interested in.

My other main topic this week is choosing when to transplant and when to direct sow. I am a big fan of transplanting, so I’ll start with that.

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

Advantages of transplanting:

  • You can start earlier in the year than you can outside, and so get earlier harvests
  • By starting seed in more ideal conditions in a greenhouse, (or on a kitchen windowsill), you’ll get better growth, more satisfaction!
  • It is easier to care for new seedlings indoors – major weather events stay outdoors!
  • You can fit more crops into each bed throughout the season, because each crop is occupying the bed for less time than if direct-sown.
  • Transplanting. can help you grow more successions of summer crops, as each one needs less time in the garden or field. This helps you always have good quality fresh produce for harvest.
  • If you don’t want or need to plant more food crops, you can use those time windows for quick cover crops, such as buckwheat in warm weather, mustards in cold weather.
  • You will save on seed costs, because you’ll be sowing and spotting or potting up, then transplanting, not sowing long rows and thinning most of the plants out.
  • Using transplants fits (better than direct sowing does) with using plastic (or paper) mulches, which can help with weed control and soil warming (or cooling).
  • Using transplants fits well with no-till cover crops. Mow or roll-and-crimp the cover crops, transplant into it, and the dead mulch keeps the weeds away for 6-8 weeks in our climate, longer in cooler and drier climates.
  • Transplanting works well for crops where you want several varieties, such as tomatoes and peppers.

    Amy’s Apricot tomato from Southern Exposure Seed Exchange. Transplanting works well for crops where you want a few plants each of several varieties.
    Photo Pam Dawling
  • You have more flexibility if the weather turns bad, for example if spring is cold and/or wet. You can delay transplanting. Your plants still grow, provided the roots have enough space. If you know they won’t, you can pot them up to provide more root space.
  • At transplanting time, you can select the sturdiest plants, and compost the rest, meaning you have the best chance of good yields.

Disadvantages of transplanting:

  • If you extend the season and start earlier, you will have more work. . .
  • You’ll need to spend extra time caring for the starts indoors, as they won’t get water if you don’t provide it.
  • Transplant shock can delay harvest, so be sure to learn and practice good techniques
  • More attention is needed to watering new plants after transplanting, (compared to direct seedling) as some root damage is almost inevitable. (Plug flats and soil blocks minimize root damage)
  • If you don’t have a good irrigation system or water supply, growing many transplants will be a challenge.
  • Likewise you do need a good greenhouse set-up to grow many transplants.

Advantages of direct seeding:

  • See the disadvantages of transplanting.
  • Direct seeding is less work than transplanting. Put the seed in the ground, water as needed and stand back!
  • You do not need a greenhouse or special transplanting equipment
  • Compared to buying starts, direct sowing has lower costs
  • Direct sown crops have better drought tolerance – the roots grow without damage
  • Some crops just don’t transplant easily: melons which have fragile stems and roots for instance, or carrots which get distorted roots if transplanted.
  • Some crops have millions of plants and you couldn’t possibly transplant enough:  (Carrots)

    Carrot rows thinned to 1 inch. Carrots are too numerous to transplant and transplanting stunts and distorts the roots, so they are best direct sown.
    Photo Kathryn Simmons

Disadvantages of direct sowing:

  • See the advantages of transplanting.
  • Direct sowing uses more seed than transplanting.
  • Direct sowing requires more time thinning
  • Direct sown crops occupy the land longer than the same crop transplanted.
  • Some direct-sown crops may be harder to get started in cold (or hot) conditions.

There are probably others, do let me know!

For those wanting to sow large-seeded crops through plastic mulch, see below for how we planted beans.

To sow beans through biodegradable plastic mulch, we made this dibble from bamboo, dowels, a culled hammock stretcher bar and plumbing strapping. Photo Nina Gentle
Using the bean dibble to punch holes through the plastic mulch (the soil is holding down the edges of the mulch).
Photo Brittany Lewis
Sowing beans through holes we made in the biodegradable plastic mulch.
Photo Nina Gentle
Beans growing on biodegradable plastic mulch.
Photo Nina Gentle