Cabbage is a cool-season vegetable that thrives in moderate temperatures but suffers in extreme heat or prolonged cold. Successful planting requires aligning the growth cycle with the mild temperatures of spring and fall. Planting at the wrong time can cause plant loss from frost or premature flowering, known as bolting, which makes the head bitter and inedible.
Spring Planting for Early Harvest
The goal for a spring crop is to establish plants early so they mature before summer heat arrives. Gardeners typically use transplants rather than direct-sowing seeds to gain a time advantage. Set these young plants into the garden bed approximately two to four weeks before your region’s last expected frost date.
Cabbage is relatively hardy and can tolerate light frost once established, allowing for early planting. Mature plants can safely tolerate temperatures down to around 20°F. However, young seedlings are more vulnerable; prolonged exposure to temperatures below 45°F can trigger bolting. Seedlings require protection if a hard freeze is predicted during their initial establishment phase.
Fall Planting for Late Harvest
Fall planting allows cabbage to mature during the cooling temperatures of late summer and autumn. This gradual drop in temperature helps sweeten the cabbage heads and improve flavor. Unlike the spring crop, the fall planting date must be calculated backward from the first expected frost date in your area.
To determine the correct window, consider the variety’s specific maturity time, which ranges from 60 to over 100 days. Count the maturity period days back from the first expected fall frost date. Then, add an additional two to three weeks to account for slower growth as daylight hours shorten. For example, an 80-day variety should be transplanted roughly 10 to 12 weeks before the first frost, usually in mid-to-late summer.
Preparing Seedlings and Soil
Before transplanting cabbage seedlings outdoors, they must be “hardened off” to acclimate them to the outdoor environment. This involves gradually exposing the indoor-started plants to sunlight, wind, and cooler temperatures over a seven- to ten-day period. This slow transition, which begins when seedlings are four to six weeks old, prevents transplant shock and stunted growth.
The soil should be rich, well-draining, and contain plenty of organic matter to support the plant’s heavy feeding habits. Cabbage thrives in a slightly acidic to neutral pH, ideally ranging between 6.0 and 6.8, which helps prevent diseases like clubroot. The soil temperature should be around 50°F to 60°F for optimal root establishment and continued growth.