Collard is one of the most primitive members of the cabbage family. They are closely related to kale and cabbage and could be described as a non-heading cabbage. They originated in the eastern Mediterranean or Asia Minor and have changed little in the thousands of years that man has used them for food. Collards are a traditional vegetable for the southeastern US and are not as popular in the rest of the US. They are grown for the rosette of smooth, rather thick and tender leaves that are used as greens or pot herbs.
Collards are low in calories and fat but are excellent sources of fiber, Vitamins A, C and K, calcium, manganese and folic acid. They are also a good source of Vitamins B2, B3, B6 and E and magnesium. People on blood thinners such as coumidan should be careful because of high Vitamin K content and people prone to kidney stones should be careful because of oxalate content.
Sun: Full Sun
Spacing: 18 – 24”
Optimum Soil Ph: 6.5 – 6.8
Days To Maturity: 75
Sowing Method: Outdoors
You can grow collard greens as either a spring or fall crop, though your greens will be more flavorful and sweeter when grown in the cool autumn. Collards are usually sown right into the garden rather than indoors for transplants.
In the spring, get your soil ready for seeds about 6 to 8 weeks before your last frost date. Dig down to loosen the soil and add in compost or aged manure for nutrients. Collards are considered to be “heavy-feeders”. Plant a few seeds every 2 feet, and thin them down to 1 plant after they sprout. Seeds should be planted just a 1/4 inch under the surface.
If you want to start harvesting young greens earlier, you can not bother with the specific spacing and just sprinkle the seeds over the soil. Cover them over with a thin layer of soil. As the plants begin to grow, you can pick the young ones for eating, until you are left with larger plants with at least 2 feet of spacing between them.
Later in the season, you can seed out your fall crop. For many people, this would be their main collard crop for the year. Follow the same planting arrangements as for the spring crop above, but start them out about 4 to 6 weeks after your last frost date.
Collard greens are one of those crops that you harvest at your leisure throughout the growing season. See the harvest section for more on how and when to pick collard leaves.
Water your plants often. Dry periods won’t necessarily harm the plant, but the leaves will take on a much stronger flavor afterwards and possibly become too bitter to eat.
Fertilizing with a high-nitrogen blend of fertilizer is a great help to boost leaf production. Just remember that this kind of fertilizer should only be used on leafy green vegetables. It will help leaves develop but will shrink or stunt any fruit or tuber formation. Regular fertilizer is also fine with collards if that is what you are using. Give your plants a feeding two or three times through the summer.
Collards do grow larger than most other greens, so you will have to have one plant per 10″ pot. Larger containers are fine with 2 plants as long as you can provide at least 18 to 20 inches between their main stalks. Keep them well-watered and well-fed with fertilizer.
Pests and Diseases
Collards are part of the Brassica family, which includes cabbage and broccoli. This also means that they are at risk from the same host of pests that plague those other vegetables (and many others).
First off are the slugs and snails common to any vegetable garden. You can buy commercial baits and traps, or drown them in saucers of beer left out at night. Diatomaceous earth is a fine white powder made from microscopic crushed shells. Harmless to animals, it will kill soft-bodied pests like slugs and snails. It can also help get rid of other caterpillars as well. Sprinkle heavily around the plants and re-apply after rain.
Cabbage worms and cabbage loopers are two different kinds of caterpillar that will do serious damage to your collard leaves if you don’t control them. Both of these pests are green so look closely at your plants or you might miss them. Insecticide sprays can usually protect your plants, and you should pick them off whenever you see them.
A harder to spot threat is the cabbage root maggot because they attack underground. If your plants are dying back for no other visible reason, dig one up and see if the roots are being eaten by small worms or maggots. Once you have them, its difficult to get rid of them. Your best approach is to keep them out of the soil in the first place. A light cover of mesh or screen in the spring can keep the moths away that lay the maggot eggs. It’s less of a problem for fall crops because the moth season has passed.
Harvest and Storage
You can start taking leaves about 4 to 6 weeks after you’ve started your seeds. If you let the leaves get too large before cutting, there may be a tough central stalk through the leave that will have to be cut out before using.
You can pick the leaves as the plant grows, always cutting off the ones at the bottom of the plant. As the inner stalk continues to grow upwards and produce more leaves, your collard plant will eventually look like a little tree with a bare stem at the bottom and leaves on the top. They will start to get top-heavy towards the end of the season and may require support.
For spring collards, your growing season comes to an end when hot weather arrives and your plants bolt to seed. The leaves will be too bitter to eat at this point. It’s not a problem with fall collards, and you can keep on harvesting well after the frosts start arriving.
Cooked collard greens can be frozen for longer storage, but the fresh leaves will only last a few days in the fridge.