Plant Brassicas Now for Fall Harvest and Holiday Dinners
By Janet Scheren, Fairfax Master Gardener Intern
Yes, you can plant brassicas in the spring as well. But in the fall they grow into the cooler weather, allowing them to reach full maturity and size with vigor. For most of the brassicas, the cool weather — and for some, even light frost — sweetens their favor and enhances their texture. This dynamic allows for an extended growing season in the fall and an extra planting for most of these crops.
Temperature governs the growth and development of these healthful, beautiful and flavorful crops. It not only affects their ability to form tightly wrapped heads and leaves, or heads of flower buds and florets, but it also sets the timing for the plant going to seed, thus signaling the end of the plant’s productive life cycle. So, it’s important to get the timing right with these cole crops.
The best approach for Virginia gardeners is to start seeds indoors in late July or early August, thus providing 12 to 14 weeks before the first average frost date. For Northern Virginia’s USDA Zone 7a, the first frost date falls between October 14 and October 25. Use grow lights and a seed warming mat for best germination and seedling development. To minimize shock, use biodegradable pots made from materials such as peat, coir, manure, TP rolls, paper egg cartons or newspaper so that they can go right in the ground with your seedlings. Plant them when the seedlings are about 4 inches high, typically at about four weeks. You can also start with transplants from your local garden center.
This family of plants prefers a sunny location with rich, fertile soil that is slightly acidic to neutral. Brussels sprouts and cabbage prefer a pH ranging from 5.5 to 6.5. Broccoli and cauliflower like a slightly more neutral pH of 6.0 to 6.7. A bed with a pH of 6.0 to 6.5 meets the needs of all. While cabbage is a medium feeder, the others are heavy feeders and need starter fertilizer when transplanted and again two to four weeks later. All four of these plants come in a wide pallet of colors ranging all the way from white to shades of purple. Check online seed companies for descriptions of the many tasty and colorful varieties for each.
Here are some key tips for your brassica crops.