In January 2020 I was part of a group tour of Cuban farming organized by the Organic Growers School. In 9 days we visited 9 farms, had several speakers address aspects of life (and particularly farming and environmental issues) in Cuba, had a couple of walking tours, ate many delicious farm-to-table type dinners and still had time for a salsa lesson.
When I got home I planned to follow up with a public slideshow, but instead we got the Covid pandemic. I made a series of blogposts, which you can revisit:
“This 9-day tour of Cuba’s sustainable farms, community gardens, and historical centers provides a rare opportunity to learn about the Cuban food system and learn about alternatives to corporatized agriculture. Participants will have the chance to:
Learn from farmers and food activists about Cuba’s transition to agroecological farming practices and its national policies that prioritize sustainable farming and hunger remediation.
Connect with farmers, consumers, activists, NGOs, policymakers, and experts working to transform the global food system.
Acquire the knowledge and strategies to create just, sustainable, local, and healthy food systems in your own communities.”
Check out the linked presentation for a summary of the January 2022 tour and for a sneak peek of the types of activities involved in the tour. OGS successfully operated a tour group in January 2022. No-one got Covid. OGS brought the first educational trip from the United States to Cuba since the beginning of COVID
On the website you can get your most likely questions answered: legal, financial and health requirements, sample itinerary, reasons to visit Cuba, reasons to go with OGS, reasons to value agroecology, and a one-hour Info session video. The trip includes bus transportation within Cuba, a minimum of 2 meals each day, 9 nights in casas particulares accommodation, a very good ag-knowledgeable tour guide and tour manager, and entry fees to various sight-seeing exhibitions.
CAFF - Extend Your Growing Season into Colder Weather with High Tunnels I’m spending October home on the farm, preparing and planting the hoophouse with winter crops. Meanwhile I’m applying to speak at quite a few sustainable agriculture conferences and preparing slideshows, handouts and talks. I’m going back to in-person conferences. We have very limited Wi-Fi in this part of rural Virginia and video-conferencing is just not possible. I managed to make some recorded narrated slideshows during the pandemic and I picked up more writing work. But there is an undeniable something I get from in-person conferences!
In the past year I’ve been at two in-person events: The very safely and carefully orchestrated PASA conference back in February, and the September CAFF presentation, half of which was outside touring the farm and half in a large airy lecture room. Now I’m lining up quite a few conferences. Go to my Events page on this website to get all the details, including links to register. Hope to see you at one of these:
I will be presenting a 75-minute workshop on Spring and Summer Hoophouse Use, especially how to manage extreme heat and diseases in hot and humid climates.
January 6-8 (Fri-Sun), 2023, Virginia Association for Biological Farming is hosting the Virginia Biological Farming Conference, Hotel Roanoke and Conference Center. Conference INFO Home Page
I hope to be presenting a half-day pre-conference session on Friday January 6, on Year-Round Hoophouse Vegetables. Also maybe a regular length session during the main conference.
January 14, 2023 (Saturday), NOFA-MASS Annual Winter Conference. Northeast Organic Farming Association, Massachusetts Chapter.https://www.nofamass.org/conferences/Worcester State University on Saturday January 14 and online Sunday January 15. I hope to give a presentation on Saturday.
February 8-11, 2023 (Weds to Sat 2.30pm), PASA2023 Sustainable Agriculture Conference. Lancaster Marriott Hotel and Conference Center, 25 S Queen St, Lancaster, PA. https://pasafarming.org/conference/
I will be presenting two 60 min or 75 min workshops:
Alliums Year-Round (Brand New!)
Crop Planning for Sustainable Vegetable Production.
We are getting ready for fall and starting to plant our winter crops in the hoophouse.
I have written about transition to winter crops here: Planning and Growing Winter Hoophouse Vegetables (August 16, 2022). This post includes a bed plan, and links to lots of related posts, such as selecting and planning winter crops, bed prep, direct sowing and transplanting, and then caring for the crops, optimizing use of the space, harvesting, and what to do if something goes wrong,
Fall Lettuce Transition
From September 11-17 we sow to transplant in our greenhouse, and on September 15 and 24 to transplant in our hoophouse. This is our fall transition and I’ll write about that when the time comes.
On September 15 and 24, we sow leaf lettuces and romaines in an outdoor nursery bed. We transplant these into our hoophouse at 10” (25 cm) spacing. This is a bit closer than the 12” (30 cm) spacing we use outdoors. We will harvest outer leaves from the hoophouse lettuce all winter, so the plants won’t get as big as they do outdoors.
On October 23 we start sowing lettuce mix in the hoophouse. Baby lettuce mix can be ready in as little as 21 days from mid-spring to mid-fall, longer in colder weather. Our first sowing will be harvestable form 4 December to 15 May if we’re lucky, although if it gets too hot, this planting will get bitter and we’ll need to pull it up.
Baby lettuce mix is a direct-sown cut-and-come-again crop, the plants regrow and can be harvested more than once in cool seasons. We sow 10 rows in a 4’ (1.2m) bed, 4.5” (11cm) apart. Weed and thin to 1″ (2.5 cm). When 3″–4″ (7.5–10 cm) tall, cut 1” (2.5 cm) above the soil. Gather a small handful in one hand and cut with using large scissors. Immediately after harvesting, weed the just-cut area so the next cut won’t include weeds. Rake after harvest with a fine leaf rake to remove outer leaves and cut scraps. If you want to make more than one cut, you will need to remove anything that isn’t top quality salad while you can see it. Larger scale operations have harvesting machines.
We make four or five sowings of baby lettuce mix, sowing our last one on 15 February, for harvest starting mid-March, and ending in May when it gets too hot. By then we should be happily harvesting juicy lettuce heads outdoors and will have lost interest in the lettuce mix.
The soil temperature range for germination of lettuce seeds is 35-85°F (2-29°C), with 40-80°F (4-27°C) being the optimum range and 75°F (24°C) the ideal. At 41°F (5°C) lettuce takes 15 days to germinate; at 50°F (10°C) it takes 7 days; at 59°F (15°C) 4 days; at 68°F (20°C) only 2.5 days; at 77°F (25°C) 2.2 days. Then time to germination increases: 2.6 days at 86°F (30°C); after that it’s too hot.
Removing Shadecloth from our Hoophouse
We are now removing our shadecloth. Normally we would have removed the shade cloth in mid-September, or at least by the Equinox, but this year we are delayed a week. After 15 years with our initial piece of shadecloth we ordered a new piece. Well, we ordered two new pieces, because we mistakenly ordered a piece only half long enough. We bought a matching piece for the other half, and this winter we are going to sew the two pieces together with nylon twine, because the ends of each piece roll back, leaving a central gap about 6 feet long by September. Measure twice, order once!
Before next spring we need to replace quite a lot of the hooks the shadecloth ropes attach to. Next time we replace the big plastic we also need to replace the baseboards, as they are rotting and not holding the hooks well.
A reader passed on this tip: “When I ordered shadecloth for my hoophouse, I overshot each end by ten or twelve feet. We stake that out on either end, using six-foot T-posts, to give us a shaded area where air moving into the hoophouse’s open ends can be cooled before entering the structure. Every year in July and August, I’m grateful we did.”
Washing Down the Salts in the Hoophouse
Next week we will leach the salts that have risen to the surface of the soil and dried out there. My book The Year-Round Hoophouse has a whole chapter on recognizing, monitoring and reducing salts that have built-up in the hoophouse, and reducing the likelihood of problems in the future. There is also a chart of salt tolerance of various vegetables, so you can choose what to grow while you remediate your soil. Here I’ll just give a very short intro, in three slides. Click in the lower left of the first slide to move to the next one.
We are starting to close the doors at night when the temperature looks likely to drop below 50°F (10°C) outside. We had to trim down the grass to be able to push the doors to. We had to re-drill the holes the door-bolts (“cane bolts”) go down into. The doors have been wide open all summer.
In fall/winter/spring, if night time outdoor low temperatures will be below 40°F (4.5°C) here, we close the windows as well as the doors.
See my post Dealing with winter weather in your hoophouse (Jan 2022). Be ready to deal with snow and strong winds, extra cold temperatures, and holes in the plastic letting cold air in. If you have a double layer hoophouse, the air inflated between the layers adds strength to the structure, as well as thermal insulation. Holes are bad news.
SnoBrum and telescoping painter’s pole
Hat with visor
Long-handled broom with bristles covered with a towel or some bubblewrap
If you have a hoophouse, you may now be planning or planting crops for fall, winter and spring. If you don’t have a hoophouse, this is a good time of year to consider getting one. See Twenty Benefits of Having a Hoophouse at the end of that post. There are grants available from NRCS, including reparation levels of funding from traditionally underserved groups of people. There are now companies that will construct your hoophouse for you, if you don’t want to do it yourself, or can’t. If you do want to build your own, there are detailed instructions in my book The Year-Round Hoophouse. You can buy the book here on my Books page direct from me, or from my publisher New Society, or you can buy it wherever books are sold.
I have many posts about winter hoophouse vegetables, so rather than try to write something completely new on the topic, I am going to give you a guide to find your way around the information already here.
Sweet potatoes are grown from “slips,” (pieces of stem with a few leaves), grown from a mother root, not from seeds or replanted roots. We used to buy bare-root slips for transplanting, because we didn’t know how to grow our own, and had heard it wasn’t easy. We have been growing our own for many years now, and prefer the flexibility and reliability it gives us. We did make several mistakes initially, so I can warn you about what not to do. We have a system that we really like, and I have learned a few other methods that I will also tell you about, including one I helped out with the past two years, growing them in a hoophouse.
Disadvantages of buying sweet potato slips
You need to specify a shipping date months ahead, then hope for good weather and no shipping delays.
You might have late frosts, spring droughts, or El Niño wet springs, and climate change is only adding to the uncertainty, but slips that arrive in the mail need immediate attention.
You have to get them all in the ground promptly, and do your best to keep them alive (because they arrive wilting).
Some amount of drooping (transplant shock) is normal.
Advantages of growing your own sweet potato slips
You can delay planting if the weather is all wrong (frost, drenching rain, heatwave)
You can grow them big and plant 3-5 nodes underground, giving more chance of survival if there is a late frost, or an early drought.
You can plant them in stages rather than all on one day.
You can grow extra and keep them on hand to replace casualties.
The sturdy plants get off to a strong start – the transplants don’t wilt – a big advantage where the warm season is on the short side for a 90- to 120-day plant.
You have more self-reliance and less money going out.
How not to grow sweet potato slips
I made several mistakes learning to grow slips. You don’t have to repeat my mistakes! My first error – following directions written for much further south (in pre-internet days), was to try growing slips in mid-January in central Virginia. Dismal fight against nature! Likewise, I was puzzled by talk of using cold frames. Ours were freezing cold at that time of year.
Next, I set up a soil warming cable in a cinder-block-enclosed bed on the concrete floor of our greenhouse. This is how I discovered most soil warming cables have thermostats that switch off the heat at 70°F (21°C). I just couldn’t get the soil warm enough.
Three Successful Methods of Growing Sweet Potato Slips
Twin Oaks slips-in-flats method
Boutard single node cutting method
Hoophouse or caterpillar tunnel bedding method (Twin Oaks)
Twin Oaks Slips-in-Flats Method
I’ve written about this before, so I’ll just give you a link to open another page.
Starting Sweet Potato Slips discusses pros and cons of growing your own slips, and describes our “slips in flats” method, which I learned from Hiu Newcomb of Potomac Vegetable Farms. Here is our Worksheet we use to stay on track with that task.
Anthony Boutard and Caroline Boutard Hunt wrote an article about single node sweet potato propagation (which they learned from John Hart of Cornell) in Growing for Market in March 2015. They farm in Oregon and New York respectively.
Both the slips-in-flats method and this one start at the same time, planting roots in damp compost in a warm greenhouse. I corresponded with Anthony Boutard about our respective methods. He pointed out that the slips-in-flats method needs a lot of warm space to grow the slips, at a time when warm space is at a premium. Our method does take us from early March to mid-May.
The single node cutting method uses only 10-20% of the number of mother roots compared to the slips-in-flats method. It uses tiny plants in plug flats, saving on greenhouse space, and only needs 18 days between cutting the slips and planting in the field. The smaller plants can experience less transplanting shock than larger plants. On the other hand, I do not think they have the resilience that multi-node plants have, for example if a late frost strikes.
When these plants grow in the field, their root production is from the single node. This can lead to fewer, but very large tubers, an advantage or a disadvantage, depending on your goals. Better in climates with a short warm season than in hot places, although digging after a shorter growing period would be possible in warm climates.
This method can be used to grow more plants from purchased cut slips, which is very helpful if you are growing a rare heirloom with limited propagation material available. Plant the bought slips in the greenhouse and grow them on until you can make cuttings.
Like the slips-in-flats method, this one buys time if the weather turns bad and you need to back pedal on your planting out date.
To prepare single node cuttings, cut a slip from the mother tuber and cut off about ¼” (6mm) above a leaf node (the swollen point where the leaf emerges). In the leaf axil is a bud which will grow a shoot, and just below the bud is a ring of cells that can grow roots. You can trim back the leaf stem, or leave the leaf on. Make the second, lower, cut just above the next node down. You can make several cuttings from one regular slip.
50-cell plug flats work well to grow the cuttings. Push the lower end of the shoot cutting at an angle into the cell, creating an even V with the leaf stem. If a cutting is too tall to fit your cell plugs, you can cut more off the lower end. The new shoot will then grow upwards easily from the bud in the leaf axil.
Keep the trays warm and moist, and plant out after only 18 days, into well-prepared damp soil, with drip tape in place. Delaying planting for 10 days or so is not a problem.
This post includes a discussion of the Single Node Method, in an article in Growing for Market magazine by Andrew Schwerin from NW Arkansas. In warm climates, only use this method if you want really big tubers!
The Hoophouse Bedding Method
I learned this method from my friend and colleague River Oneida, who grew slips for Southern Exposure Seed Exchange. He planted up 4 beds 45’ (14 m) long with three rows/bed in a single-layer hoophouse and grew an average of 4000 slips/week, for a 6 week sales season (24,000 slips), with a peak and bell-curve ends of the season. Caterpillar tunnels could also work.
Store your saved roots at room temperature. From March 1 onward: start the sweet potatoes sprouting indoors in stages, as heated space permits, at 85°F (29°C), and high humidity. Remove any rotting potatoes. When each potato grows ¼” (6 mm) sprouts, take it out of the heated space and replace with new ones. Put the ¼” (6 mm) sprouted ones at room temperature to slow them down for batching with later ones.
In March: Cover the bed area in the hoophouse with a single layer of clear plastic, and kill any weeds that pop up. Four weeks before shipping starts (on April 1 in central Virginia), prepare the beds in the hoophouse. Dig out a flat-bottomed bed 1” (2.5 cm) deep, and set the sprouted sweet potatoes an inch (2.5 cm) apart in rows. One or two sprouts are enough. If possible, don’t bed unsprouted roots
Spread some compost, not lots. Replace the soil you dug out, on top of the sweet potatoes. Add soil from the aisles, putting 1”-3” (2.5-7.5 cm) of soil on top of the potatoes. Not more. Set out drip tape and irrigate regularly.
After bedding, stab holes in the plastic every 4” (10 cm) for respiration. Check regularly, opening the plastic on warm days once slips are visible. In mid-April or whenever you see slips emerging, remove the plastic in the daytime, but put it back for frosty nights Add more soil later to cover exposed tubers if needed. Regulate temperature if you want a faster or slower rate of production.
Some slips will be ready from the 3rd or 4th week of April onwards. If too many slips are ready at any point, pull and heel them in outdoors. Remember to water.
I first wrote this up for an article for Growing for Market magazine, and have included it in my updated slideshow, at the end of this post. It’s a great method for people growing lots of slips (for instance, for sale). It could also be used for smaller amounts, by occupying a corner of a hoophouse growing other crops at the same time.
More Posts on Sweet Potatoes
I have written a lot on sweet potatoes at all stages from propagating our own slips, growing them all summer, and harvesting. My posts include:
“Isn’t too cold for the predators to be around, Pam? unless they hibernated in the greenhouse. but even so, it’s still cold in there at night. We have some aphids too in the tatsoi and some of the lettuce, so thank you for all the tips, and the life cycle. I had not quite realized that the cycle was so short. I grow borage in the hoophouse but in the ground – the plants get large and gorgeous with clouds of blue flowers in March and April – much bigger and healthier than anything I try to grow outside. The honeybees absolutely love it and they attract are a lot of other insects too.”
Yes, it has been still too cold for predatory insects to be around, until this week, when ladybugs greet us around every corner. Our idea with the flowering plants was that by starting the plants in the fall, we’d have actual flowers earlier than if we started in “spring”, and that perhaps the extra stresses would even cause the plants to flower earlier. Apart from the borage, none of the others have flowered yet (Feb 23). We likely need to fine tune our sowing dates. We sowed at the very beginning of September and the very end of October. That two-month gap probably has better sowing dates! We noticed that some of our plants were not very cold-hardy. Some died and some had to be pruned of dead bits. Since then, we started more flowers in our greenhouse on February 1. Another thing we’re noticing since early February is that the plants in pots dry out very fast. It’s probably better to get the flowers in the ground in the hoophouse and greenhouse as soon as they are big enough, as suggested by the results of my reader quoted above, with borage.We had thought that having them in pots would enable us to move them into trouble spots.
Vegetable Crop Resources, Especially Weeds
A newly released handbook from Sustainable Agriculture Research and Education (SARE), Manage Weeds On Your Farm: A Guide to Ecological Strategies by Charles L. Mohler, John R. Teasdale and Antonio DiTommaso, is set to help us all. I haven’t read it yet (although I am looking forward to that!), so this is not a review, But these are three big names in weed science, and SARE is well-known for providing solid information on sustainable farming.
I had the great good fortune to attend a workshop by Chuck Mohler years ago, and got some realizations that forever changed my approach to weeds. Top of the list is that some weeds, such as pigweed (amaranth species), don’t distribute any seeds until they have grown very big. Until that point they are not threatening next year’s farming efforts. We used to get huge pigweed plants in our sweet corn, and fatalistically did nothing once we were in there harvesting, somehow believing it was “too late”. No, it’s not! They hadn’t seeded. We started to make a practice of pulling the huge pigweed every two days while harvesting corn. Often it was necessary to stand on the base of the corn plant to hold it in place, while pulling the weed. Then all we had to do was drop the pigweed between the rows. Sweet corn ripens in hot weather and the weeds soon died, rather than re-rooting. All those big leaves sucked the moisture right out of the plants. Be extra careful if you have spiny amaranth. We have twice eliminated this weed form our gardens, by diligent hand-pulling, only to have it reappear a few years later!
Conversely, galinsoga forms seeds very soon after germinating, while still small. This weed is one to strike early and repeatedly. It readily re-roots in damp soil. Our strategy when we are too late to hoe and have to hand-pull them, is to shake off as much soil as possible, then to either twist and break the stem (if there are not many), or “shingle” the weeds, laying them down with the roots of one on top of the leaves of the previously pulled plant, providing a surface of roots all exposed to the air, and none touching the soil. This works quite well. Timely hoeing is much better, of course!
Manage Weeds has chapters on How to Think About Weeds, Cultural Weed Management, Mechanical and Other Physical Weed Management Methods, Profiles of successful managers,and then the alphabetical rogues gallery of grass weeds and broadleaf weeds.
This book and all the online information from SARE is free of charge. You can buy print copies if that suits you better. Other good resources from SARE, while you’re at their website, include several other books:
You can find a wealth of information on my website about growing, harvesting and storing winter vegetables. There are many links here in this post (all should open in a new tab, so you won’t go down a rabbit hole), and you can also use the search box in the upper right to enter whatever vegetable you are wondering about, and “grow” “harvest” or “store”, Remember I also have several annual series of posts, on Asian greens, root vegetables, workhorse crops, alliums, cooking greens, and lettuce. Just don’t look for “Storage lettuce” until April 1st.
I’ve also included some good blogs that I sometimes consult.
Fall and Winter Vegetable Growing
Season extension into cold weather
Prepare your garden for colder weather: plant winter crops if there is still time, use rowcover on hoops to protect crops from wind and cold weather, plant up every little bit of space in your greenhouse or hoophouse.
Shannon suggests using a variety of strategies. “Plant some vegetables that will mature quickly, others that will hold well in your garden beds, and still others that will overwinter and begin growing again when the days lengthen.”
Good late season vegetables: salad greens, Swiss chard, beans, peas (in climates milder than 7), carrots, radishes, senposai, spinach, pak choy, cabbage and winter lettuces.
Good cold hardy vegetables: Plant in late summer and fall to harvest throughout the winter. These late-sown crops reach full maturity before seriously cold weather, and hold so you can harvest them when the rest of your crops have been eaten. They don’t usually grow much during the winter, but they do stay fresh. Grow enough to supply your needs without depending on any further growth. This category includes Asian greens, beets, broccoli, Brussels sprouts, cabbage, carrots, collards, kale, leeks, scallions, spinach, turnips and other root vegetables,
Good crop protection so you can grow some crops through the winter. If your winter temperatures routinely drop below 25 F (- 4 C), crops need protection, from simple rowcover to hoophouses or greenhouses. This improves the temperatures, but it’s hard to address the reduced amount of daylight or sunlight. The increased warmth, plus the protection from winds, can be enough for some, such as spinach, kale and lettuce, to make some growth whenever their temperature is greater than 40F (5C).
Good slow growing crops to harvest outdoors in late winter or early spring. In this category are crops that go into the winter less than fully grown. After the winter solstice, when the days begin to lengthen, crops start growing again, making them usually ready for harvest very early, much earlier than any crops planted after the solstice. They don’t usually need winter protection and include beets, some types of broccoli, cabbage, carrots, collards, kale, onions, garlic, garlic scallions, spinach, kale and collards.
Good crops to grow in hoophouses include arugula, beets, chard, Chinese cabbage, collards, kale, lettuce, Maruba Santoh, mizuna, mustards, pak choy, parsley, radishes, spinach, tatsoi, Tokyo bekana, turnips and Yukina Savoy
We like to eat lettuce year round, and have put time and energy into finding the varieties and planting dates that work best here in Central Virginia, as well as how to get the best results in each season. Recently I revised our lettuce schedules, partly to take account of hotter weather arriving earlier in the year, and also to even out the harvest dates.
I have frequently written blogposts about growing lettuce. And I have a whole year of Lettuce for the Month posts. See here for the overview, or click on the month you want to know more about. These posts are mainly about our favorite varieties for each time of year.
Back in 2006, I wrote Lettuce: Organic Production in Virginia for VABF. We’re now in Winter Hardiness Zone 7a. Back then we were 6b. Read this publication for details you are hazy on, but see our updated Lettuce Varieties List and Lettuce Log in this post.
Choose appropriate lettuce varieties for each time of year.
Sow several varieties each time to spread the harvest season and the risks of poor germination. I like to use something fast, something slow; at least one red; a romaine, a bibb and a couple of leaf types.
Consider multileaf lettuces too, Salanova and Eazyleaf brands. They are bred for uniformly small leaves, with more texture, loft and flavor than baby mixes and faster harvesting. Transplanted 6″–8″ (15-20 cm) apart they produce 40% more than baby leaf mixes. The full-size plant can be harvested as a head, providing a collection of bite-sized leaves. Or just one side (or the outer leaves) of the plant can be cut and the plant will regrow for future harvests. Growing multileaf heads takes 55 days, compared to 30 days for baby lettuce
Our recent changes to our Lettuce Varieties List include switching over from “Early Spring” varieties to “Spring” varieties at the end of February rather than the end of March. This means we only make 3 sowings of the early spring varieties, and we need to stop buying much seed of those varieties! Next year I might even abolish that category and those early varieties to simplify life.
The spring varieties we now sow from February 28 to April 22. We used to sow these until May 15. We’re still making 5 sowings of those, but the dates have moved earlier.
On April 23 we switch over to our Summer varieties, which we make 20 sowings of, until August 14. (Buy lots of seed of those varieties!) We then switch to nine sowings of Fall varieties, until September 7.
From September 8 to the end of September we use our cold hardy varieties. These 9 sowings include those for the greenhouse and hoophouse, which will feed us all winter.
You’ll need a large screen, a magnifying glass or the ability to expand the image.
We like to grow a balance of leaf lettuce and head lettuces, and, in winter, baby lettuce mix too. We harvest the baby lettuce mix when 3″–4″ (7.5–10 cm) tall, cutting 1” (2.5 cm) above the soil. We harvest leaves from the big lettuces the rest of the time. Baby lettuce mix is very pretty, but I actually prefer the juiciness and crunch of big lettuce.
Keys to year round lettuce
·Store seed in a cool, dry, dark, mouse proof place.
·Grow your lettuce quickly, for high quality and flavor, using good soil preparation and high organic matter.
·Learn the skills of lettuce germination in all weathers. Minimum soil temperature for germination is 35°F (1.6°C). Optimum temperature range for germination is 68°F–80°F (20°C–27°C).1/4″–1/2″ (6–10 mm) deep is ideal. Good light.
Watch the temperature – Germination takes 15 days at 41°F (5°C), 7 days at 50°F (10°C), 3 days at 68°F (20°C) and only 2 days at 77°F (25°C). Germination will not occur reliably at temperatures hotter than 86°F (30°C).
Keep watching the temperature – Optimum growing temperatures are 60°F–65°F (15°C–18°C), Some growth occurs whenever the temperature tops 40°F (4.5°C).
·Choose good locations! We grow lettuce outside from transplants from February to December (harvesting from late April); in a solar-heated greenhouse from September to March (harvesting leaves from November) and in a solar heated hoophouse from October to April (harvesting leaves from November, and whole heads in April). We also sow baby lettuce mix in the hoophouse from October to February, for harvest multiple times from December to April.
·Use shade cloth on hoops in hot weather
·Use rowcover in cold weather, or plant in cold frames, greenhouses or hoophouses.
Lettuce under shade cloth. Photo by Nina Gentle
Grow a consistent lettuce supply using succession crop planting
To have a continuous supply, it is important to plant frequently, at intervals adapted for the time of year. The gap between one sowing and the next gets smaller as the year progresses; the gap between one transplanting and the next does likewise. The number of days to reach transplant size dips to 21 days in the summer, then lengthens as the weather cools and the days get shorter.
We made a Lettuce Succession Crops graph using our records for sowing date and harvest start date. From this we determined the sowing dates to provide us with a fresh harvest (120 heads of lettuce, or equivalent) every single week. We made a Lettuce Log with our planned sowing, transplanting and harvest dates. This is explained in my slideshow Lettuce year round.
Recently I fine-tuned this in light of more recent records. In some cases we had been led astray by a spreadsheet date calculator that was based on 30 day months in a 360 day year! Not reality! We also had data showing that transplants were not always ready on the dates we had thought, probably due to a mistake in an earlier year when we were unable to transplant on time, and repeated the delayed date the next year. Most of the tweaking was in early and late spring, and then in August.
I recommend transplanting lettuce (other than baby lettuce mix) at 4-6 true leaves (3-6 weeks of age). It is worth learning good transplanting skills, so that plants thrive, even if transplanted in mid-summer.
Water enough, with an efficient irrigation system. Water new transplants daily for the first 3 days, then every 4-7 days after that. Lettuce needs a relatively large amount of water throughout its growth. Deeper weekly waterings equivalent to 1” (25 mm) of rain are better than frequent superficial irrigation – roots will grow deeper, giving the plant greater drought-resistance.
To make best use of space and time, plant lettuces 10-12” (25-30 cm) apart, in a hexagonal pattern. If you plant too close, you are restricting the size of the lettuce. If you plant with more space than needed, you will waste time dealing with more weeds!
Transplanting gets a head start on weed control, which is important from planting to a couple of weeks before harvest. Don’t waste time hoeing lettuce you will be harvesting next week. I generally find that if I hoe once, a couple of weeks after transplanting, that is all the weed control I need at the fast-growing time of year. We like the stirrup, or scuffle, hoes, which are safer in the hands of novices than sharp edged hoes, because the blade is in a closed loop.
Some growers use black plastic mulch, but I hate filling the world with single use plastic, so we don’t do that. Some others use landscape fabric with melted holes at the right spacing. I used this for strawberries and liked it. I’m not sure I’d find it worthwhile for fast-growing lettuce. No-till growers can transplant into mulch, first making what we call “nests” at the appropriate measured spacing. It’s tempting to skip the measuring, but if you drift from a 12” (30 cm) spacing to a 15” (38 cm) spacing, you will end up with fewer lettuces!
For those who like to direct sow lettuce, you could prepare the bed, let it rest for a week (watering it), then flame or lightly hoe the surface before sowing to remove a flush of weeds.
Bolting and/or bitterness are more likely with under-watering, long days, mature plants, poor soil, crowding, high temperatures, and vernalization—once the stems are thicker than 1/4″ (6 mm), if plants suffer 2 weeks of temperatures below 50°F (10°C), followed by a rapid warm-up.
Deal promptly with pests and diseases. Aphids, cutworms, slugs, rabbits, groundhogs and deer all like lettuce as much as we do. If you find your lettuces melting down with fungal diseases, you can, of course, commit to better crop rotation. You can also consider solarizing beds for next year’s lettuce. You need a minimum of 6 hot weeks in which to cook the soil-borne disease spores by covering the prepared beds tightly with clear plastic. Old hoophouse plastic is ideal – construction plastic does not have the UV inhibitors that prevent the plastic shattering into shards.
If you haven’t already made a plan for winter cover crops, this is a good time to do it. Having plants growing through the winter, or at least into the winter until they get killed by cold temperatures, will improve your soil both physically (the roots hold the soil in place, preventing erosion, and they open up channels that improve the drainage) and biologically (the soil microorganisms thrive when they have active plants to cooperate with, exchanging nutrients). Cover crops will also reduce the number of weeds you have next year, because they crowd out weed seedlings. In some cases they even inhibit weed seeds from germinating.
I have some slideshows about cover crops, and am including one at the end of this post.
Choosing the “perfect” cover crops can be confusing, but any is better than none, so I encourage you to experiment and keep records, so you can improve your choices each year. It helps to know your first frost date, and your winter-hardiness zone (the lowest temperature your garden is likely to encounter). A two-week delay in sowing can seriously reduce the effectiveness of the cover crop, so follow these guidelines if you can.
Short Simple Guide to Winter Cover Crops
If the area has been fully harvested of food crops by 60-80 days before frost, sow a frost-killed cover crop or even a fast-growing food crop. Buckwheat, soy, cowpeas, spring peas, sunnhemp, Japanese millet, sorghum-sudangrass will frost-kill. Forage radish lab-lab bean or bell beans will die back and leave almost bare soil. Don’t sow a winter cover crop yet. If sown too early, oats head up in the fall and even drop seed.
If the area is clear of vegetable crops by 40-60 days before frost, sow oats to winter-kill. If possible add a legume (soy and spring peas are easy, and will be killed by the frost, so they won’t complicate food crops next year). For us with a first frost date of October 14, the cut-off date for oats is September 7. This would be after growing early sweet corn, spring broccoli, cabbage, spring-planted potatoes or early season spinach, lettuce, beets, carrots. Oats will winterkill completely at 6°F (-17°C) or even milder than that, leaving the plot quick to prepare for early crops next year. So plan to put your early crops where you had oats in the winter. See the slideshow for more about oats.
If the area is ready for cover crops 20-40 days before frost, sow winter wheat. Add a legume such as crimson clover, if you won’t need to prepare the area before it flowers (in central Virginia 4/16-5/2, most usually around 4/20). You get the most nitrogen from the legumes if they reach the flowering stage before you kill them off in spring. If you have a legume that doesn’t reach flowering, it’s not the end of the world, you just get less nitrogen for your money. It is too late to usefully sow cover crops that are not frost-hardy, or even oats, which won’t make enough growth before getting killed.
If the area is ready for cover crops up to 10 days past the frost date, sow winter wheat or winter rye and hairy vetch or Austrian winter peas. Winter rye is hardier than any other cover crop and can take later planting dates. But it is a bit harder than wheat to incorporate in the spring. Austrian winter peas can be sown later than other legumes.
If you are up to3-4 weeks past your average frost date, (we choose November 7 here, where our average first frost is October 14), sow winter rye alone. It’s too late for any legumes.
If you are later than 3-4 weeks past your average first frost date, leave the weeds or crop remains growing. It’s too late to sow a cover crop, and you’ll do more harm than good tilling up the soil. You can mow the weeds anytime you see lots of flowers and seed heads. The weed roots will hold the soil together and help feed the soil microorganisms until early spring. Be prepared to act soon in spring, so you don’t get weed seeds.
More Options for Each of These Time-frames
60-80 days before frost: You could follow a frost-tender cover crop with an over-wintering cover crop, for best effect. If you leave the dead tender cover crops in place, in early spring the winter weeds will start growing in the open space, so be ready for fast action. For the very earliest spring crops, forage radish lab-lab bean or bell beans will die back and leave almost bare soil. While still growing, they suppress weeds. BUT fast-maturing spring vegetables will not do well with no-till cover crops unless you add N fertilizer, as they need nitrogen more quickly than can be got from no-till.
40-60 days before frost: Austrian winter peas, crimson clover, or red clover are other options for legumes, but they won’t die when the oats do. They are relatively easy to incorporate in spring. Frost-killed cover crops can also be combined with oats. Or for a cover crop to survive the winter, sow winter barley or winter wheat with Austrian winter peas, crimson clover, hairy vetch, red clover, fava beans. Hairy vetch takes a few weeks longer than crimson clover to reach flowering. Which you choose will depend what you want to grow there next spring and when you need to plant it. After oats or other winter-killed cover crop, we like to plant our early spring food crops, peas, cabbage, broccoli, carrots, March-planted potatoes, spinach and the first sweet corn.
20-40 days before frost: Winter rye, or winter barley are also options for the cereal grain part of the mix, if you have those seeds on hand. In central Virginia, it’s a mistake to sow rye as early as August, as it can set seed. Austrian winter peas, or red clover are other legume options if that’s what you have. Sometimes it pays to use what you already have, as it may not give good germination if saved over to next fall. Winter rye needs 3-4 weeks after tilling in, in spring, to break down and to disarm the allelopathic compounds that stop small seeds germinating. Plan for the next food crops to be ones planted after late April, such as late corn plantings, winter squash, transplanted watermelon, tomatoes, peppers, sweet potatoes, June-planted potatoes, fall brassicas, and second plantings of summer squash, cucumbers, beans.
Up to 10 days past the frost date: it’s too late for clovers. Austrian winter peas winter-kill in zone 6, but are hardy in zone 7. Hardy to 0°F (-18°C). AWP bloom in late April at Twin Oaks, before hairy vetch. Suitable crops in the year before using Austrian winter peas are the late-finishing winter squash, melons, sweet potatoes, tomatoes, peppers, middle sweet corn, June-planted potatoes. The same group of crops are suitable for following AWP, as they are planted after May 1. You can sow AWP several weeks later than clovers, but at least 35 days before first hard freeze (25°F/-4°C) – in zone 7, 8/10–10/24 (11/8 is sometimes OK)
Up to3-4 weeks past your average frost date: no really, it’s too late for any other cover crop. If you don’t have winter rye, don’t till! Leave the weeds, see below.
Later than 3-4 weeks past your average first frost date: no, really, do not till! You could mow and tarp, to kill the weeds before spring. I’m not sure what the soil life thinks about that, though! You could mow again in early spring, or till and sow oats, if you won’t be planting a food crop in the following 8 weeks, giving the oats time to make respectable growth before turning them under.
Create a crop rotation for vegetables that includes good cover crops
If you include winter cover crops when planning a crop rotation for your vegetables, you can tweak your plan to maximize your cover crop opportunities. Here’s the steps:
Figure out how much area is needed for each major crop (the ones needing the largest amount of space).
Measure and map the space available
Divide into equal plots big enough for your major crops
Group compatible crops together to fill out each plot
Set a good sequence, maximizing cover crop opportunities
Include best possible cover crops at every opportunity
Try it for one year, then make improvements
For more details, see my slideshow Crop Rotations for Vegetables and Cover Crops on SlideShare.net
Advanced Options for Winter Cover Crops
Sometimes you can undersow the cover crop between the rows of a growing food crop, to take over after the food crop dies of frost or mowing. We do this with our last planting of sweet corn, and with fall broccoli and cabbage.
Timing is critical: Sow the cover crop late enough to minimize competition with the food crop, but early enough so it gets enough light to grow enough to endure foot traffic when the food crop is harvested. The leaf canopy of the food crop should not yet be closed. Often the best time is at the last cultivation, often about a month after planting the food crop. With vining food crops, it’s important to sow the cover crop before the vines run.
Choose vigorous food crops, but cover crops that are only moderately vigorous. Ensure the seedbed is clean and the soil crumbs small enough. Use a high seeding rate, whether broadcasting or drilling, and irrigate sufficiently.
No-till Winter Cover Crops
In the spring, kill the cover crop without tilling it in, and plant food crops into the dying residue. There are three ways to kill cover crops without herbicides:
Winter-killed cover crops for early spring food crops
Mow-killed cover crops.
Roll-killing (but it usually requires special equipment).
We have had one year in 10 as a no-till year. We use no-till cover crops before Roma paste tomatoes, which are transplanted in early May. We don’t need early-ripening for these, making them a good no-till food crop. The soil under no-till cover crops stays colder than tilled soil, slowing the plant growth down.
Late-spring transplanted crops such as late tomatoes, peppers, eggplant, Halloween pumpkins, or successions of cucumbers and squash can do very well after a winter-hardy legume-grass mix no-till cover crop.
To be an effective mulch, you need to get a thick sturdy stand of cover crops, which means sowing in plenty of time, and being generous with the seed. To make the timing work, you need a previous food crop that finishes before the sowing date 4-5 weeks before the average frost (that’s September 7-14 for us).
Timing is also critical in the spring. For maximum N, the legumes in the mix will be flowering right when you need to plant the food crop. Mow the cover crop mix close to the ground, and plant right into the stubble. Transplants or big seeded crops work well. The ground will be relatively hard – you probably can’t make a furrow for small seeds).
It’s not all over with the weed-prevention after that. In our humid climate the no-till mulch biodegrades after 6-10 weeks. In July we roll hay between the rows, to top up the mulch.
I’ve chosen 14 Workhorse Crops (including two pairs) to focus on at the beginning of every month, until April 2022: These are crops that we can rely on under a wide range of conditions. Some Workhorse Crops are easy to grow, some pump out lots of food, some are “insurance crops”, some are especially profitable (for those growing for market), and watermelons are the circus pony among the workhorses, I admit, but we all need fun!
I intend for this series to help growers who want to become more efficient, productive and profitable (if selling) as we emerge from sheltering at home and expand our lives again. Don’t give up growing your own food, just choose some less time-consuming ways to do it.
Workhorse Crops to Plant in June
June is another busy planting month here in central Virginia. Next month the heat strikes hard, and the daylight starts to get shorter, but this month we are still climbing the hill of the year. Ten of our 14 Workhorse Crops can be planted in June.
Beans: We sow bush beans every few weeks to keep up supplies of tender beautiful beans. See the Special Topic section for info about Succession Planting, to help you determine when and how often to sow beans and other short-lived warm weather crops. Also see the Special Topic section to read how we control Mexican Bean Beetles that used to destroy our bean plantings. Click this link to read about soaking bean seed, using inoculant, sowing through biodegradable plastic mulch using a jig, sowing sunflowers in our bean rows as place-markers when harvesting.
Carrots: I wrote a lot about carrots in the past year, when the monthly series was on root crops. See this post on preparing beds for sowing carrots, and weeding and thinning. Check out this post on flame-weeding, if you plan lots of carrot-growing!
We sow carrots in late February, then twice in March, once a month in April and May and after that we’d like to not sow more until the beginning of August. Carrots grown in hot weather don’t taste that good: there’s little sweetness and too many terpenes (the compound that in small quantities gives carrots their distinctive carrotiness, but can be overpowering if too strong.) But home-grown hot weather carrots are still better than jet-lagged travel-weary carrots from afar. You could use shadecloth over the beds. If we have not grown enough carrots by the end of May to see us through to October, we sow in June, and even July if we must.
Chard: The perfect insurance crop! We use chard for fresh greens in summer, when spring kale, collards, broccoli and cabbage have long bolted and been turned under so we can plant something else. We transplant our chard into a hay mulch in late April. Organic mulches help keep the soil cool during hot weather, so are very helpful for leafy greens. This crop will be in the ground until mid-winter, and mulch will keep back most of the weeds.
Chard provides leafy greens all summer whenever you need them, and you can ignore it when you have plenty of other vegetables! As a biennial, chard will not bolt the first year (unless stressed by lack of water). I’ve noticed the red chards bolt more easily than the green ones. I suppose red crops are a bit stressed already, as they are short of chlorophyll, compared to the green ones, making photosynthesis harder work.
Potatoes: I wrote a special series on potatoes last year. Click the link to access the whole series, starting with planting in April. Here we plant in March and June. For our June-planted potatoes, we pre-sprout the seed potatoes for just two weeks (shoots grow quicker in warm weather than in early spring). To protect the planted potatoes from the summer heat, we hill immediately after planting, even though we can’t see the rows! Then we unroll big round hay bales down the field to cover all the soil. Potato shoots grow strongly, and can make it up through the extra height of the hills/ridges and through the 3” (7.5 cm) of hay. After about 16 days, we walk through the field, investigating spots where there is no sprout. We call this task “Liberating the Trapped Shoots”. Often the problem is just an overthick clump of mulch, and the shoot will be quite literally trapped (and completely white). We simply let he shoot see the light, and redistribute the over-thick mulch.
Sweet corn: we make 6 sowings of sweet corn, to harvest from July 4 to mid-October. We are well into corn-planting time, which continues until mid-July, when there are not enough warm days left in the season to mature another sowing. Remember: don’t plant a mixture of different corn genotypes, and don’t plant Indian corn, popcorn or any kind of flint or dent corn within 600′ (180 m) of your sweet corn. This leads to very disappointing starchy corn. We grow only sweet corn in our garden, to avoid this problem.
Sweet potatoes: I wrote a lot about planting sweet potatoes in 2020. Wait for the soil to warm before planting out your sweet potato slips, they don’t grow well if too cold. We plant ours a couple of weeks after the last frost, around the time we transplant peppers and okra. In early June, we replace any casualties, if needed, to fill out the rows again. This year we have a beautiful looking patch, with rows of healthy plants on ridges, with biodegradable plastic mulch. We have a solar-powered electric fence to deter the deer. My latest worry is groundhogs, who can slip right under the electric fence. They haven’t yet, but I expect they will, if we don’t catch them first.
Tomatoes: In mid-June we plant a bed of late tomatoes, to boost the yields when the maincrop beds start to pass their peak. We planted our main crop tomato beds at the very beginning of May, and they’re looking quite good.
Here’s a post about planting tomatoes in our hoophouse. We use the same techniques in the hoophouse and outdoors. We transplant one row of tomatoes down the centerline of a 4ft (1.2 m) bed, 2ft (60 cm) apart. Once the weather has settled so that we’re confident we won’t need rowcover any more, we stake and stringweave. We install a steel T-post every two plants (4ft /1.2 m) apart and start stringweaving when the plants are about 12ins (30 cm) tall. I’ll say more about stringweaving next month.
Watermelons: As I explained in May, I gave watermelon a “Circus Pony” place among the workhorses! They’re not easy, therefore not reliable, but they provide so much pleasure when they do grow well. We transplant our watermelons, to get ripe ones as early as possible.
Watermelons grow very well on black plastic mulch, which warms the soil as well as keeping weeds at bay. The first year we switched from using hay mulch to biodegradable plastic mulch, we were astounded to get ripe melons a full month earlier!
If you want to use organic mulches for warm weather crops, don’t do it immediately. Wait till the soil warms through. This year we made that mistake, then we had late cold weather and the transplants all died. We’re going to experiment with station-sowing seeds directly in the gaps. Station-sowing is a technique of putting several seeds in the ground at each spot (station) where you want one plant to grow. Rather than making a furrow and sowing a row that needs thinning later. It’s a good technique for remedial work (ahem!), or if growing very expensive seeds, or for crops you are not familiar with, such as parsnips. You see several seedlings all the same and can be pretty sure it’s the thing you planted.
Watermelons can be planted from seeds when the ground has warmed to at least 70°F (21°C). On average, it takes about 85 days for Crimson Sweet seedlings to mature and produce ripe fruit. This is late for us to sow watermelons, and we certainly won’t get early ones this year, but we could get them in September. Better than none.
Winter squash are a true workhorse, and can still be sown here early in June, provided we don’t sow the slow-maturing ones like the gigantic Tahitian Butternut. Aim for harvesting in September and October and count back to see how many days you have until you want to harvest. Then choose the varieties that will have enough time. You can also transplant winter squash if you need to. We did this once when our fields flooded. It worked out fine.
We mostly grow Butternuts, Moschata types that store best. This is the type to focus on if you want squash with no damage from borers or cucumber beetles. The tougher stems are better able to repel invaders. They need warm growing temperatures above 60°F (16°C).
See last month’s post for more about sowing winter squash, and for other kinds of winter squash, such as some Maxima squashes that store quite well and have relatively high resistance to squash bugs compared to others in this group, and Pepo squashes, suitable for storing a few weeks only
Zucchini (courgettes) and summer squash: another crop type that we succession sow, to get a continuous supply. More about succession planting below in the Special Topic section. We make five or six plantings, each one half yellow squash (Zephyr, Gentry) and half zucchini (TenderGrey, Noche, Golden Glory). We grow our earliest squash in the hoophouse, setting out transplants at the beginning of April. Our first outdoor crop is also from transplants. After that, the soil is warm (60°F/15.5°C) and we direct sow. The time from sowing to harvest is only around 42-54 days.
After transplanting or sowing, we hoop and cover the row with insect netting (rowcover works if it has no big holes). We have many bugs that like these plants, especially the striped cucumber beetles, so we keep the rows covered until female flowers appear. At that point we need the service of the pollinators, unless the squash is parthenocarpic (sets fruit without pollination). We pack away the covers, hoe and thin the squash to 24” (60 cm). It would be better to thin sooner, but we rarely find the time.
Workhorse Crops to Harvest in June
We have mnemonics for harvesting: Monday, Wednesday and Friday might be the crops beginning with the plosive Ps and Bs: peas, beans, beets, broccoli, blueberries etc. Tuesdays, Thursdays and Saturdays would be the crops beginning with the hard K and G sounds: kale, corn, carrots, collards, cabbage, garlic scapes etc.
Other crops like asparagus, lettuce, cucumbers, summer squash and zucchini we harvest 6 days a week. Some, like cabbage, we harvest twice a week.
Asparagus can be harvested here until early in June. Every day for the 8-week harvest period, snap off at ground level all the spears above a certain length. We chose 7” (18 cm). This task is best done first thing in the morning, when the spears are crisp. Daily harvest will also remove asparagus beetle eggs, controlling the pest level.
Cabbage is ready here from late May until mid-July. We store enough to feed us until we start harvesting fall cabbage. An early sowing of fast-maturing varieties (like Farao or Early Jersey Wakefield which can be ready in only 60 days) can be followed by harvests of slower varieties. When a cabbage is ready for harvest, the head is firm and the outer leaf on the head (not the more horizontal wrapper leaves) will be curling back. For cabbage to store to eat over the summer, cut with a strong knife and set it upside down on the nest of leaves to dry a little. Come back along the row with a net or plastic bag and gather up the storage quality cabbages to refrigerate. Gather any lower quality cabbages to eat soon. If you would like to get another harvest from the same plants, cut criss-cross into the stump. Small “cabbagettes” will grow and can be used raw or cooked. They won’t store.
Carrots can be ready about three months after sowing in spring, although you can get thinnings for salads sooner. Read here about harvesting carrots.
Chard is ready for harvest as soon as you decide the leaves are big enough. Simply snap or cut off some outer leaves and stand them in a bucket with a little water until you cook them. For a sustainable rate of harvesting with chard, always leave at least 6 of the inner leaves to grow.
Garlic harvest time will be soon if not already. I wrote about garlic last week.
Kale and collards can be harvested until they are bolting, as long as the flavor is acceptable. Our spring-planted ones are not bolting yet, but the fall-planted ones were tilled in a couple of weeks ago.
New potatoes could be dug here during June, if you don’t mind reducing the final yield. The flavor of new potatoes, with their delicate skins, is very special. As a child, I ate them boiled with mint, and topped with some butter.
Tomatoes start to ripen this month. Our hoophouse tomatoes have started to yield a small amount of Glacier, Stupice, Sungold and Amy’s Apricot.
Zucchini and summer squash are ready from the hoophouse early sowing since about May 20. We are now (June 2) harvesting our first planting of outdoors. We harvest every day to the fall frost (or beyond if we remember to cover that last planting with rowcover on chilly nights.).
From storage: carrots, potatoes,
Workhorse Crops Special Topic:
Succession planting, and Mexican bean beetles
Succession planting is a topic I have often presented at workshops, so rather than give you more words, I’m giving you the slideshow from 2019. Towards the end it includes information about dealing with Mexican bean beetles.