Cabbage propagation provides gardeners with options to begin their harvest either through traditional seed starting or by utilizing kitchen scraps. Cabbage is botanically a biennial plant, meaning it takes two years to complete its life cycle, but it is routinely cultivated as an annual to produce the edible, dense head within a single growing season. For a successful harvest, understanding the timing and environmental requirements for the two primary propagation methods—seed starting and core regrowth—is necessary to ensure plants thrive until they are ready for the garden plot.
Starting Cabbage from Seed
Beginning cabbage plants from seed indoors gives gardeners a significant head start on the cool-season crop, allowing for an earlier spring harvest. Seeds should be sown indoors approximately six to eight weeks before the final expected spring frost date. This timing is designed to produce robust seedlings ready for transplanting when outdoor conditions are optimal.
The small seeds should be planted about one-quarter inch deep in a sterile seed-starting mix, which provides a light, disease-free environment for initial root development. Maintaining a soil temperature around 70°F is beneficial for encouraging quick germination, which typically occurs within seven to fourteen days. Once the seedlings emerge, the air temperature should be reduced to a cooler 60°F to 65°F to promote compact, sturdy growth rather than long, weak stems.
Seedlings require a significant amount of light to prevent stretching. A bright grow light placed a few inches above the emerging plants for 14 to 16 hours daily will help develop strong, thick stalks. Keeping the soil consistently moist but never saturated is important; watering from below once the seedlings have sprouted helps reduce the risk of damping-off disease.
Regrowing Cabbage from the Core
Regrowing involves using the stem or core left over from a harvested head of cabbage. This technique utilizes the plant’s natural ability to sprout new growth from its basal plate. To begin, select a fresh cabbage core that still has a small portion of the head and the basal stem intact.
The core is placed cut-side up in a shallow container with just enough water to submerge the bottom one inch of the stem. The container should be positioned in an area that receives bright, indirect sunlight, such as a windowsill. It is important to change the water every few days to prevent the growth of mold or bacteria that could cause the stem to rot.
Within a week or two, small roots will begin to emerge from the base, and new leaves will sprout from the top of the core. While this method can produce new, edible leaves for continual harvesting, the regrown plant may eventually “bolt,” or send up a flower stalk for seed production, especially when subjected to environmental stress. The resulting new growth, whether harvested as leaves or allowed to form a small, loose head, is a simple way to extend the use of kitchen scraps.
Managing Seedlings and Transplanting
Once the cabbage seedlings have developed two to three sets of true leaves, they are ready for the next stage of care. If multiple seeds were sown in a single cell, the weakest seedlings must be thinned out, leaving only the strongest plant to continue growing. This step ensures that the remaining plant has adequate space and resources for proper development before moving outdoors.
The transition from a sheltered indoor environment to the outdoors requires a process called “hardening off,” which takes approximately seven to ten days. This gradual acclimatization strengthens the plant tissue, making the seedlings more resilient to direct sun, wind, and temperature fluctuations. Plants should be placed outside in a shady, protected area for only a couple of hours initially, with the exposure time and sunlight intensity increasing each day.
After the hardening off period is complete, the sturdy seedlings are ready to be planted into the garden plot, two to three weeks before the last frost date. Cabbage thrives in fertile, well-drained soil rich in organic matter and requires full sun exposure. Seedlings should be spaced 12 to 24 inches apart, depending on the variety, with closer spacing resulting in smaller heads. The plant should be set in the ground at the same depth it was growing in its container, and immediately watered to settle the soil around the roots.