Updated 11/16/2024
Ready To Grow Fall Greens and Vegetables?
It’s hard to believe it’s already time to start seeds for fall greens and vegetables. I’ve been putting it off because of the hot weather we’ve been having. But, unless I want to buy transplants, seeds will have to be started soon. You folks up north probably have sown seeds for the broccoli and cauliflower by now, and certainly the Brussels Sprouts.
Here in North Carolina, fall seems a long time away, but in order for us to harvest those fall greens, we need to start sowing seeds now. Remember to locate your fall/winter garden where it will receive adequate sunlight. And, of course, I’ll sow successive crops through the rest of summer and early fall, as space permits.
Because we have a long growing season in the Carolinas, we can squeeze in another crop of summer vegetables. Zucchini, summer squash, cucumber, and beans can be sown again. But with the encroaching canopy of the trees on the berm, south of the garden, I’ll be planting only cool-season vegetables for late summer and autumn harvests. The ‘Diva’ cucumber is loaded with fruits. And I will wait patiently for every last fruit to ripen on the tomatoes and peppers.
(***Update***: A few days ago, a large and dangerously crooked pine tree was taken down, and now there’s more afternoon sun for the tomatoes and peppers. More sun also gives us opportunities to grow containerized vegetables and fall greens inside the fence, protected from deer. August 2018)
If They Can’t Take the Heat
Temperatures are still too high to sow lettuce and spinach outdoors, so I’ll wait another week or two. It’s still in the 90’s! They can be started indoors, in air-conditioned space, if needed.
Check the temperature of the soil before sowing seeds in the garden. Direct sun beating down on the dark soil surface can raise the temperature too high and dry it out very quickly. Look for one of those “Easy Tunnels”, or fabricate something yourself, to partially shade the soil and the tender young seedlings. You can purchase knitted shade fabric, made from black polyethylene, from mail order suppliers. In the southern states, 30-50% shading should work during the late summer months. This could lower the temperature by 10° or 15°F. Keep the soil surface moist to ensure good germination and to cool it down.
The best germination occurs between 55° and 70°F for lettuce and spinach. I usually put transplants into the garden instead of sowing seeds directly because hungry slugs, snails, and cutworms find tiny seedlings very tender and delicious.
Organic Sluggo will bait the mollusks (slugs and snails) to their deaths, and Bacillus thuringiensis (Bt), sprayed on the seedlings, will kill cutworms. Slug baits made with iron phosphate, such as organic Sluggo, are far less harmful to pets and to people than products containing metaldehyde, so be sure to read the labels.
One way to gather up a whole lot of slugs is to place a board, maybe 1′ x 2′, over damp soil. Go out and check the underside early the next morning, old knife in hand, and cut them quickly in half or squish them any way you choose…but, don’t use salt in the garden!
Choosing Varieties of Fall Greens
Sowing seeds for fall greens and vegetables, which prefer cool weather, can be tricky in July’s heat. Look online or through seed catalogs for lettuce, spinach, broccoli, and other crops that are described as being heat tolerant varieties. Yes, all lettuce and broccoli varieties prefer cool temperatures, but some will take warmer or colder weather than others as they form heads. If you’re buying transplants, ask the grower.
Either way, plan to provide some sort of device that will lower the temperature during these last hot weeks of summer. For later harvests, I’ll sow seeds that grow cool and mature in cold weather, and they will not need the shade fabric. Plants grow better with more hours of direct sun as the temperatures cool down.
Check with your local agricultural extension office for recommendations or for a planting calendar.
Planting Young Transplants
Soil
Starting a vegetable garden with soil that has not been conditioned could result in a mediocre or poor harvest. Fall greens grow faster and larger in well-prepared soil.
Garden soil for these crops needs additional organic matter (compost, composted cow manure), drainage material (pine fines, coarse sand), and sometimes lime. A soil test will indicate the need for lime.
Our fall greens are being planted in soil that has been worked for 6 years, so it’s in very good condition. I will, however, continue to add compost, fertilizer, or manure to the garden with all new plants.
When digging soil, bring some of the lower-level clay up to the surface, and turn under the richer topsoil 4″ to 6″ deep (a few inches deeper for tomatoes, in spring). Over time, the clay soil on the surface will improve as mulch decomposes or when compost is added as a top dressing. Here you can see clumps of light brown clay that were brought to the surface of the soil (photo, above) before they were broken up.
Roots
Growers use pots and market packs of various sizes, including small 9-cell packs, 4-cell packs, 2″ peat pots and 4″ plastic pots. A smaller root ball needs more careful monitoring while the plant becomes established.
An important step before planting is to rough up the outside of the root ball (photos, above). This slightly injures the inner root layer called the pericycle, stimulating the plant to quickly send out new lateral roots into the soil. Be careful not to so severely damage the root system that the plant can’t supply water to the leaves on a hot, sunny day. Do this for every plant that is about to be repotted or planted into the garden.
A root ball that’s tightly packed with roots can be shallowly scored down the sides in a few places. Use a knife, a rock, or even a twig. Or use a cultivator to pry out some of the roots.
To Bury or Not To Bury?
Most young vegetable transplants can be placed an inch deeper into the soil, or up to the bottom leaves. If the plant is more mature and has developed a somewhat woody or tough stem, plant it at the same level it was growing in the pot. But always, if possible, choose younger transplants.
Older plants can be stressed by being potbound or underfertilized, and might go to flower or head up prematurely, yielding undersized harvests. Young plants require more time to grow, but they will give you the largest heads of lettuce, broccoli, cauliflower, and cabbage. If in doubt, plant the top of the root ball level with the soil surface.
Firm the soil around the roots and stem using medium pressure. Humidity between the soil particles encourages the stem to grow fine roots without interference from tightly packed soil. Watering the plant helps the soil settle in around the root system and charges the soil with much-needed moisture.
These are same broccoli ‘Arcadia’ plants photographed in late December (photo, above). Trees on the berm cast too much shade until leaves dropped off, delaying harvest. When the garden gets more sun, heads should form in mid to late winter.
Fertilizer for Fall Greens
Planting fall greens and vegetables into late September, I mix a handful of granular organic vegetable fertilizer into the planting area. These crops grow beautifully with adequate nitrogen, so I will soon use higher nitrogen fish emulsion. Another application of fish emulsion will be made every 2-3 weeks through November, or every 2 weeks for potted greens.
Microbes in the soil break down organic compounds and make nutrients available to the roots. But, as the weather cools significantly, microbial activity slows down. I’ll use synthetic soluble fertilizers a few times in winter to keep the plants growing.
Greens and vegetables can grow all winter here, with some protection during very cold weather. This is worth the effort, since I can pick beautifully fresh kale and spinach for the Sunday omelet, or a big bunch of collards for collards soup.
Mustard greens ‘Florida Broadleaf’ was sown in late September, and germinated a few days later. The thinned seedlings will be used in soup, salad, or an omelet. Spinach sprouted about a week later.
Arugula
Love, love arugula! A forkful of salad greens that has a piece of arugula in it…mmm… The variety I prefer is ‘Astro’. It’s not as hot as the wild types, and it tolerates warmer temperatures. Arugula self-sows if it likes where it’s growing. Just let it flower and set seed. The papery seed capsules release the seeds, which germinate within 2 weeks, during favorable weather, near the mother plant.
It grows well in morning sun, during warm weather, and in moist, rich soil. Those who are more adventurous than I might enjoy growing the hotter ‘Wasabi’. Arugula doesn’t look like a member of the family Brassicaceae, but it, too, is in that famous family.
You might have seen the term “cruciferous” being used when describing members of the Brassicaceae family (formerly Cruciferae). It refers to the flowers of these plants, which have 4 petals arranged in the shape of a crucifix. The terms brassica, cole crops, and crucifer (or cruciferous) refer to the same plants.
Broccoli
One of the most nutrient-rich foods, broccoli is a must in my garden. Nutrients include protein, Vitamins A, several B’s, C, K, minerals, fiber, and their famous phytonutrients. To say that we eat broccoli in one form or another every 2 or 3 days is not an exaggeration. Just ask Mother.
Heat and cold tolerance ranges from poor to excellent, depending on the cultivar. In this zone 7b area, ‘Imperial’ can be sown in July or planted as transplants from July through August; Johnny’s Selected Seeds’ catalog rates it “excellent” in heat tolerance for broccoli. Normally, broccoli grows best in cool weather, but you can extend the harvest by choosing 2 or 3 varieties that are suited to the weather at different times of the year.
The variety that will see us through the winter is cold-hardy ‘Arcadia’, which grows a large number of side shoots once the main head has been harvested. For that reason, don’t cut off too many leaves when you do harvest broccoli, because each of those leaves could be topped by another side shoot.
By the way, tender broccoli leaves are edible as well. Add them to soup, a smoothie, pasta, or a stir-fry. After the harvest is done, I keep the plants in the garden to flower. Bumble bees and other early risers are fond of this bounty, and the flowers are quite pretty!
Miniature Broccoli ‘Happy Rich’
I’ve grown ‘Happy Rich’ for many years. This plant grows a small head at the end of a stem, harvested ideally before the white flowers open. Each of those little green beads is a flower bud, and even if the buds start opening when the stems are picked, they’re still going to the kitchen.
The head will never get to the same size as regular broccoli, but the flavor is superb. Once the little heads have been cut off with 6″ to 10″ of the stem, the plant will branch out and grow more little heads. The stem, the leaves, and the head are edible—steamed, stir-fried, or added to soup or a pasta dish.
Two plants have been growing in the garden since the spring, and they don’t look very happy. It’s been a hot summer in Charlotte, so I didn’t expect them to survive this long.
***Update***: In autumn, 2021, I moved to a larger property in the Piedmont, with lots of gardening potential. In the photo, below, ‘Happy Rich’ produced harvests for over 9 months in 2022. An Arctic Blast just before Christmas, when the temperature dropped 50 degrees to the low single digits, put an end to this planting. This area is in USDA zone 7b, so average temperatures allow growth all through the winter for many types of greens…usually. 11/16/2024
Bt
The imported white cabbage butterflies visit frequently—more frequently, alas, than I do with the bottle of Bt.
Bt is an abbreviation for Bacillus thuringiensis, a naturally-occurring bacterium that kills caterpillars of moths and butterflies, and nothing else. Before you groan “no chemicals”, Bt is used by organic growers and it’s been around for decades. Perfectly safe, even for pollinators, and not a chemical. It easily rinses off produce. You can find both organic and conventionally prepared products.
All brassica crops are targeted by a few kinds of moths and one species of butterfly, which lay eggs on the leaves. The eggs soon hatch into voraciously hungry and well-camouflaged caterpillars. After consuming some of the Bt, they stop feeding and die shortly thereafter. Young caterpillars are more easily controlled than older caterpillars. Thuricide and Dipel are two brand-name products with Bt as the active ingredient.
Page 1: Ready To Grow Fall Greens and Vegetables?, If They Can’t Take the Heat (Choosing Varieties of Fall Greens), Planting Young Transplants (Soil, Roots, To Bury Or Not To Bury?, Fertilizer for Fall Greens), Arugula, Broccoli, and Miniature Broccoli ‘Happy Rich’ (Bt)
Page 2: Brussels Sprouts, Cabbage, Cauliflower, Collards, Kale, Lettuce, Nutritional Considerations of Fall Greens (The Sulforaphanes, Where’s the Beef?), and Only the Beginning