How to grow Greens
For all greens, nitrogen is a necessity - the more nitrogen that is available,
the bushier and leafier your greens will be. Prepare your soil with a
nitrogen boost before planting, then side dress with nitrogen throughout
your growing season to maintain leaves.
Also, temperature is a key factor with greens. Most can withstand light
freezes, especially when covered with a plant-protector fleece. However,
temperatures above 75oF will usually cause most greens to bolt (begin
flowering to produce seeds, ie, the end of their season) - it’s important to
understand your area’s temperatures in order to decide if fall or spring
growing is better for your greens: in southern climates with hot summers
and mild winters, fall is the best growing season, while in northern
climates with longer springs and harsher winters, early spring planting
gives the best production. If you’re unsure, you can always start your
greens in the fall and cover them as needed. A hard freeze can kill your
greens, but light freezes will often make the leaves taste crisper.
Pests are similar on most greens as well. Cabbage loopers and other types of caterpillars are drawn to leafy greens, but as they are mostly grown in cooler weather, pests are often a sign that it is too warm and the plant will bolt soon. Flea beetles, cucumber beetles, harlequin bugs, and aphids can be prevalent in greens, so always be sure to wash your greens before eating. Because greens are directly edible, take care with any pesticide use and be sure it is marked for vegetable gardening on the label.
If growing microgreens, these are often best done indoors, in controlled environments. Add sterilized potting soil (to prevent fungus and gnats) to a propagation tray, or use seed mats. Liquid fertilizer is best for this use, but isn’t a requirement. With microgreens, spacing isn’t really an issue, because your seedlings will be used when small. Microgreens do need to be kept moist, but too much moisture can promote mold. Harvest when your microgreens are of a usable size. Use scissors to cut the tops, leaving the roots intact and leave a few lower leaves if you want them to regrow.
Cabbage seeds can be started indoors and transplanted outside, which is ideal if your area is still too hot, or if you’re saving for a spring planting. For spring, start your seeds 6-8 weeks before the last frost date. For fall, start your seeds 10-12 weeks before the first frost date. Cabbage seeds need the average temperature to be between 65-75oF to germinate. Plant your seeds only 1/4-1/2” deep. You can also soak the seeds overnight in tepid (lukewarm) water to give them a head start germinating. Keep seedlings moist, but be sure that your soil drains well. Greens with wet feet tend to rot. Cabbage seeds (and most greens) will have initial leaves, but need 2-3 sets of true leaves before they can go outside. If starting indoors, you’ll transplant the cabbage 6-8 weeks before the first frost date in fall or 2-3 weeks before the last frost date for spring plantings.
You’ll need an area with 6 hours of full sunlight, and be sure not to plant near other brassicas, like cauliflower and broccoli, and strawberries and tomatoes. Good companion plants are cucumbers and beans.
Plant cabbages 2’ apart and do the transplant on a cloudy day to prevent shock to the seedlings. Add mulch - ground leaves, finely ground bark, or compost, then water deeply (mulch usually sucks up water, so you need to water more to penetrate the extra layer). Keep your seedlings well watered, you’ll water them about 1.5”/week until they approach maturity. Stop watering about 3 weeks before harvest to prevent splitting.
Add a nitrogen rich fertilizer when the head begins to develop. You’ll determine if the head is ready to harvest with a squeeze test. The head should be between 4-10”, and when squeezed, it should be firm. If it is soft or loose, it needs more time. Once you harvest the main head, if you remove it carefully and leave the stem in the ground, they can regrow new, smaller heads which will mature sooner. Chinese cabbage grows upright and will only make one head.
Extra cabbage heads can be stored for later use. Clean the heads from dirt and bugs and let dry. You can wrap it in plastic and store in the fridge for 2 weeks, store it in a cellar for up to 3 months, dry or freeze it, or make sauerkraut!