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Collard Greens (Brassica oleracea var. acephala)

Collard Greens - Vegetable 

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(Best months for growing Collards in New Zealand - temperate regions)

S = Plant undercover in seed trays T = Plant out (transplant) seedlings

  • Easy to grow. Grow in seed trays, and plant out in 4-6 weeks. Sow seed at a depth approximately three times the diameter of the seed. Best planted at soil temperatures between 8°C and 30°C. (Show °F/in)
  • Space plants: 40 - 50 cm apart
  • Harvest in 8-11 weeks.
  • Compatible with (can grow beside): Dwarf (bush) beans, beets, celery, cucumber, onions, marigold, nasturtium, rhubarb, aromatic herbs (sage, dill, chamomile)
  • Avoid growing close to: Climbing (pole) beans, tomato, peppers (chili, capsicum), eggplant (aubergine), strawberry, mustard

Collards are a member of the same plant genus – Brassica – that includes cabbage, kale, broccoli, cauliflower, Brussels sprouts, and kohlrabi, among others. Collectively, these plants are often referred to as “cole crops.” You may also hear them called “cruciferous” vegetables or “brassicas.” The word “cruciferous” derives from “Cruciferae,” the former family name for what is now called “Brassicaceae.”

The collard’s loose leaf form means it is less susceptible – although not immune – to the fungal diseases that can plague plants in this genus. This is an important consideration for cultivation in the South, where high humidity offers fungal diseases a welcoming environment. In addition to having good heat tolerance, these plants are also known for their preference for a cool growing season. Collards can reach 20-36 inches in height and 24-36 inches in width. They’re hardy in zones 8-10, which means they’re perennials — which may live several years — in warmer regions. In other zones they may be grown as annuals

Growing collard greens

Collard greens thrive in cold weather, and in fact are the most-cold hardy of all the Brassica species. If you live in a warm climate, the best time to plant is in fall for a harvest throughout the winter months. Choose a location that gets at least four or five hours of sunshine per day. Since this plant is a biennial, when spring arrives and the weather warms up, plants will bolt and set seed. Collards prefer full sun, but will tolerate a few hours of light shade, and they have a few soil requirements:

  • Deep
  • Well-drained
  • Rich in organic material
  • Fertile
  • Weed-free

Harvesting collard greens

You can begin harvesting collard leaves whenever they’re the size you want to eat them.  Typically this is at around 40 days, but it can be as early as 28, or even younger as we mentioned above regarding thinning. You can harvest the entire plant, or you can simply cut off outer leaves as needed, allowing the plant to continue growing.

Health and nutritional benefits

As a group, brassicas are appreciated for their nutritive value. Collards are high in fiber, manganese, folic acid, calcium, and vitamins A, C, and K, though some of their nutritional value can be lost through the cooking process. Aside from being a beautifully green and leafy addition to the garden, they are also highly nutritious! Like most vegetaables, they are low in calories and high in essential nutrients. One cup of cooked collard greens has a modest 42 calories. It packs 179 milligrams of calcium, or about 18 percent of the recommended daily intake for adults. Consuming one cup of the cooked greens also meets 7 percent of your daily magnesium needs, 20 percent of daily dietary fiber needs, 6 percent of phosphorus needs, and 54 percent of vitamin A needs.

Eaten raw, they are just as nutritious, but remember that you need to eat a higher volume to get to the same nutrient totals. Raw, they offer a measly 12 calories per cup. If you’re looking for a good source of folate, raw greens are recommended over cooked. One cup of raw greens provides 46 micrograms of folate, where one cup of cooked greens only offers 20.5 micrograms.

They are a good source of calcium, which is commonly known to support bone health. Most calcium is used to aid bone structure and function, but it also supports muscle function, nerve contraction, and dilation of veins.

Vitamin A is another key nutrient. Vitamin A allows us to be able to see, by helping to make a protein that absorbs light in our retinas. Additionally, vitamin A supports immune health and cell growth.

They offer a boost of dietary fiber as well. Fiber is important for regulating the digestive system, encouraging the production of helpful gut bacteria, regulating blood sugar, and helping to balance cholesterol levels.

Phytochemicals also play a role in the health benefits that this leafy veggie has to offer.

Indole-3-carbinol or I3C is a phytochemical found in these and other cruciferous vegetables that may be associated with antioxidant and cancer-preventing properties. More research is still needed surrounding this compound and its effects.

If you are going to use Collard Greens to treat an existing health condition please consult with your healthcare provider first.