Kale contains higher levels of beta-carotene than any other green vegetable, and is also high in vitamin C and calcium. Collards are not far behind. All are easy to grow, vigorous, nutritious, resistant to cold, and easy to harvest and prepare. And the greens even get sweeter after frost. They are perfect for juicing and a long-lasting green that stores well, delicious in crunchy salads. Continue reading below for some expert tips on how to grow kale and collards.
Brassica oleracea var. acephala
Season & Zone
Season: Cool season
Exposure: Full sun
Zone: Winter hardy to Zone 6.
Direct sow in early spring to mid-summer for summer to winter harvests. Or start indoors 4-6 weeks before the last frost, and transplant out as soon as the soil warms up. Optimal soil temperature: 10-30°C (50-85°F). Seeds should germinate in 7-10 days.
Sow 3-4 seeds 5mm (¼”) deep in each spot you where a plant is to grow. Thin to the strongest plant. Space 45-60cm (18-24″) apart in rows 75-90cm (30-36″) apart.
Ideal pH: 6.0-6.8. Add lime to the bed 3 weeks prior to sowing. Kale likes well-drained, fertile soil high in organic matter. This plant prefers plentiful, consistent moisture. Drought is tolerable, but quality and flavor of leaves can suffer. Mix ¼ cup of complete organic fertilizer into the soil beneath each transplant, or use 1 cup beneath every 3m (10′) of seed furrow.
Kale and collards can both be grown as a cut and come again crop for salad mixes by direct-seeding and cutting baby leaves. They will re-grow if you pick leaves from the bottom up, as you need them. Continue harvesting lower leaves as they mature—plants will keep producing all season. Kale can overwinter in many areas. In fact, the leaves get sweeter after frost, though growth will slow. In spring, the surviving plants start to flower, so eat the delicious flowering steps and buds.
Diseases & Pests
Protect from cabbage moths and other insect pests with floating row cover. Prevent disease with a strict 4-year crop rotation, avoiding planting Brassicas in the same spot more than once every four years.
All Brassicas benefit from chamomile, dill, mint, rosemary, and sage. Avoid planting near eggplants, peppers, potatoes, or tomatoes, as the acidic soil these plants thrive in can cause problems for Brassicas.
More on Companion Planting.