Collard (Brassica oleracea) is a brassica vegetable, related to cabbage, broccoli and cauliflower. Steamed or boiled, collard greens provide a satisfying, nutritious side dish. The greens can also be used to make tasty soups. Native to the United States, collards are easy to grow and love cooler temperatures; the leaves can be picked and eaten throughout the season. The collard plant is biennial, meaning that the first season is spent growing and maturing, while reproduction -- flowering and seed bearing -- occurs in spring of the second year.
For the collard plant to produce seeds, it must first be healthy and thriving. To give the plants the strongest start possible, add two to three pounds of 8-16-16 fertilizer per every 100 square feet of soil two weeks before planting them in a full sun location. Check that the soil pH is between 6.0 and 7.5 to provide optimal nutrient absorption. Combat pests at the first sign of an infestation. Caterpillars, such as the cabbage looper and others in the Lepidoptera order, can be managed with Bacillus thuringiensis, a biological pesticide.
When to Pick Seed Pods
Like lettuce, collards thrive in cool weather and will bolt, or produce seeds, when temperatures heat up. The plant will overwinter and then reappear to flower and produce seeds in the spring. After it flowers, you’ll notice pods that resemble green beans. Discontinue watering the collard plants and allow the pods to turn brown and dry out. Don’t harvest them too early because green pods don’t produce viable seed, even if they are set out to dry after harvesting. If you leave the pods on the plant too long, on the other hand, birds may swoop down and steal them or they make crack open, dropping the seeds to the soil. Collard seeds should be black when removed from the pod. Store them in a brown paper bag in a cool, dry place until you’re ready to plant them. The seeds should remain viable for at least four years.
Planting Collard Seeds
Sow collard seeds in February through April or July through October in most areas. If you live in a cool, foggy area, such as along the coast, you have the opportunity to plant in January but lose October as a planting month. Plant collard seeds 1/2 inch deep, in rows set 18 to 30 inches apart. Collard plants need at least 18 inches of space surrounding them for proper growth.
Something else to be aware of is that the collard cross-pollinates with other brassicas, so you’ll need to control the plants during the pollination period. The best way to do this is to choose the collard plants from which you want to harvest the seeds -- strong, productive plants are ideal -- and then dig up the others and any other brassicas nearby before they produce flowers. If any of the plants have already flowered, cut off the flowering stalks and continue to harvest the leaves, as needed.
- University of Hawaii: Collards
- International Seed Saving Institute: Basic Seed Saving
- Carrie McCracken TRUCE Community Garden: Collards in Bloom, or, What’s Going on with the Yellow Flowers?
- High Mowing Organic Seeds: Organic Kale & Collards -- Growing and Seed Saving Info
- University of California Marin Master Gardeners: Gardener’s Checklist for Summer
- San Francisco Seed Library: Planting Calendar for San Francisco
- Vegetable Crops; Dennis R. Decoteau
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