Cabbage is a cool-season vegetable that thrives in moderate temperatures, optimally between 45°F and 75°F. Missouri’s climate permits two separate growing periods: spring for an early summer harvest, and late summer for a fall or early winter harvest. Successfully navigating the state’s last spring frost and the onset of summer heat is the core challenge for the Missouri cabbage gardener.
Spring Planting: Targeting the Early Harvest
The spring cabbage crop is timed to mature before the intense heat of a Missouri summer arrives, which can cause the heads to split, bolt, or develop a bitter flavor. Gardeners should begin the process by starting seeds indoors approximately six to eight weeks before the average last spring frost date for their region. This indoor head start allows the seedlings to establish a robust root system before encountering the unpredictable outdoor conditions.
Transplanting the seedlings should occur early, generally two to four weeks before the last expected frost, or as soon as the soil is workable. Seedlings require a gradual transition known as “hardening off,” which involves slowly introducing them to outdoor conditions like wind and direct sun over about a week. This process strengthens the young plants, making them more resilient, as mature cabbage can tolerate temperatures as low as 20°F for short periods.
Fall Planting: Scheduling for Cooler Weather
A second, often higher-quality, crop of cabbage can be harvested in the fall, as the cooler temperatures enhance the plant’s sweetness. The timing for the fall crop is determined by counting backward from the first anticipated hard frost, allowing 60 to 100 days for the specific variety to reach maturity. This requires planting transplants into the garden between late July and mid-August.
The primary difficulty with fall planting is starting seeds during the high heat of mid-summer, when soil temperatures can hinder uniform germination. Gardeners often find it more reliable to start seeds indoors or purchase transplants ready for the garden. If starting seeds outdoors, planting them slightly deeper helps conserve moisture and provides a cooler environment for successful germination. The goal is to have the heads mature during the cooler days of September and October, allowing them to be sweetened by a light frost.
Site Selection and Soil Preparation
Cabbage is a heavy feeder that requires specific conditions to produce large, firm heads. The planting site must receive at least six hours of direct sunlight each day for optimal growth. The soil needs to be rich, well-draining, and high in organic matter to support the plant’s rapid development.
Amending the planting bed with aged manure or compost before transplanting improves the soil structure and fertility. Cabbage has a high demand for nitrogen, especially in the early stages of growth, which supports the development of lush foliage and large heads.
The soil pH should be maintained in a range between slightly acidic and neutral, ideally from 6.0 to 6.8, which also helps to discourage soilborne diseases.