Cauliflower

Cauliflower is the most temperature-sensitive of the common brassicas. It needs a long stretch of cool weather — ideally between 60 and 70 degrees Fahrenheit — to develop a tight, well-formed head. Too cold as a seedling and the plant may button, producing a tiny, unusable curd on a short stalk. Too warm as the head forms and the curd loosens, turns ricey, or browns within days. There is essentially no margin for error at the end of the season.

Start seeds indoors about six weeks before your last frost, and transplant out around the frost date into well-prepared soil. Cauliflower is a heavy feeder — work a generous amount of compost into the bed, and side-dress with a balanced organic fertilizer three weeks after transplanting. A plant that stalls for lack of fertility will never fully recover. Fall plantings, timed to mature in cool autumn weather, are often more reliable than spring crops because the season is cooling rather than warming.

Most white cauliflower varieties need blanching — tying the outer leaves over the developing curd to shield it from sun. Exposure causes the white curd to turn yellow or purple and develop a stronger flavor. Check the developing curd daily once it reaches a few inches across; tie the leaves when the curd is about 2 inches wide and harvest 7 to 12 days later. Colored varieties like Cheddar (orange) and Graffiti (purple) do not need blanching and can be harvested based on size alone.

Buttoning is the failure mode that catches spring growers most often. It happens when a young transplant experiences prolonged temperatures below 40 degrees — the plant interprets this as a completed vernalization period and forms a small head prematurely. This produces a curd the size of a golf ball on an underdeveloped plant with no chance of recovery. Avoid transplanting weak or undersized seedlings into cold soil, and do not rush the planting date if a cold stretch is forecast.

Harvest when the curd is fully formed, tight, and still white (or the expected color for colored varieties). Once the surface starts to separate or turn granular, flavor and texture decline quickly. Cut the head with a few wrapper leaves still attached — they protect the curd during handling. In the refrigerator, an unwashed head keeps for about a week. Leave blanched heads in the garden too long and they will brown, loosen, and develop off flavors even in cool weather.