Greens are a mainstay in the Florida Cool Season garden. Leafy greens are nutritious as well as bountiful in a well maintained vegetable garden. When harvested and prepared properly in the kitchen, they make many excellent and interesting side dishes.
Cool Season vegetable crops are those crops that can be planted in the Florida vegetable garden that will grow well during the shorter, cooler days of late fall through winter. The vegetables need the cooler temperatures to help them germinate, grow, set fruit and mature. They may even benefit from a light frost, as it converts the starches into sugar and improves the taste. It is important to plant Cool Season crops late enough in the fall so that they can complete their full cycle up to harvest before the temperatures get too warm, usually at the beginning of March.
The Brassica (cabbage) family is a remarkable group of Cool Season vegetables comprising of cabbage, collards, mustard, broccoli, cauliflower, Chinese cabbage, bok choy, kale, kohlrabi, radishes and turnips. Swiss chard and spinach are more closely related to beets and offer great tasting greens too. When planted at the right time of the year in the vegetable garden, you will experience five very productive months for growing greens.
Some of these greens are planted once and grown for up to five months as “cut and come again” crops such as mustard and collards. As the plant grows, remove the older leaves for the kitchen table and leave the new leaves and center of the plants alone. They will grow more leaves so you can come back and cut some more at a later date. Leaf lettuces could also be considered “cut and come again” crops.
I have intentionally left out Brussels sprouts. Unless we have a very cool winter, I have not had much success with them. That doesn’t mean you should leave them out if you want to grow them. However, if the winter is not cool enough, don’t be discouraged. Perhaps you will try again.
We should grow these crops in full sunny locations, in soil that has been amended with plenty of organic matter. Give the plants enough space so they grow to mature size. Keep the soil moderately moist and provide a complete fertilizer that has a moderate amount of nitrogen for best growth. Nitrogen may cause a lot of leafy growth (OK for collards, kale, mustard and cabbage). Lower nitrogen applications are better for broccoli, cauliflower, kohlrabi, radishes and turnips where we are growing crops for the compact flower buds or tasty roots. Broccoli, mustard, collards, cabbage and kale can be fertilized every three weeks. Fertilize cauliflower every 4 weeks. Keep weeds and caterpillars under control.
Brassica seeds can be planted in a container in September to grow transplants but they all do equally well being planted directly in a well amended garden bed. Don’t over plant to reduce the amount of thinning required. Usually, a small pinch of seeds placed in the soil about ¼” deep at the correct spacing, approximately every 12”, will be sufficient for an excellent crop, and you may actually have some seeds left over for next year’s Cool Season vegetable garden.
There are many pests in the Cool Season vegetable garden that like to eat greens too. These pests include caterpillars such the cabbage looper, diamondback moth, armyworms, cutworms and the cabbage webworm, and leaf feeding beetles. Aphids, whiteflies and stink bugs/stink bug relatives feed on the leafy greens. Fortunately the caterpillars are easy to control when they are young by using products that contain Bacillus thuringiensis. Beetles and bugs will need an appropriate insecticide but the Florida Vegetable Garden Guide does not list an organic control at this time. Aphids and whiteflies can be controlled with insecticidal soaps. The soap spray should be applied directly to the insects to be effective. I find that oil sprays on leafy green vegetables can cause harm to the leaves if over applied.
Develop your own Integrated Pest Management (IPM) strategy for your garden. Identify the pest first. Decide if the pest is causing enough damage to require a control strategy. Once you determine what the pest is and that it needs control, then select the best method/pesticide to control that pest.
Keep the gardening soil moderately moist throughout the growing season. Avoid overhead irrigation from sprinklers or hoses to reduce the incidence of diseases. Drip irrigation systems work well when crops are growing so close to the soil. If irrigating with reclaimed water, it is also highly recommended to keep the water off the plants. Of course, always rinse your vegetables with drinking water before eating them.
Weeds are also pests in the vegetable garden. They take up space, compete for nutrients and water and are often a host plant for many of the pests we experience in the garden. Hand pulling them is a good control strategy as there are few herbicides recommended for the garden.
UF/IFAS Gardening Solutions discusses harvesting and cooking information. Some greens can be eaten raw in a salad such as kale and spinach. Greens can be sautéed with oil and spices for a bold flavor. For Southern preparations, you can boil the greens with onion, garlic and some kind of smoked meat such as a smoked turkey wing or a ham hock. The liquid from these boiled greens, called pot liquor, can be eaten separately with corn bread.
Most of all, care for the garden as needed and enjoy the best tasting vegetables ever — your own.
Come back and read more about the “New Vegetable Gardener.”