Cabbage plants grow easily and provide beneficial nutrients, but you must provide the plants with appropriate services to boost their growth. A cool-season vegetable, it is possible to plant cabbage in spring to crop before the hot summer months or plant them in late summer to crop before frost. Purchase cabbage plants from your regional nursery or — if you have room — start seeds indoors about 60 days before the last spring frost. You can use cabbage to make coleslaw and sauerkraut, or you can wrap the leaves around a savory meat mixture to make cabbage roles.
Loosen the soil to a depth of about 12 inches before planting to ensure it is easy for roots to spread. Till about 4 inches of compost and other organic substance, such as aged manure, leaf mold or sphagnum peat moss into the garden soil to improve drainage and soil structure.
Set transplants outside for a couple hours every day to harden them off before planting in the garden. Plants should be prepared to plant after about two weeks and when all danger of frost has passed.
Space plants about 15 to 18 inches apart to allow enough room for the heads to achieve maturity. Plant seedlings deeply, burying about half of the primary plant stem. You can sow seed 2 inches deep in the soil, spaced about 2 inches apart in late summer for a fall harvest; when seedlings emerge, leave only the very best plants to supply the appropriate spacing. When your cabbage plants grow to about 5 inches tall, thin out additional plants to supply 18 to 24 inches of space between plants.
Expand a 1-inch layer of organic mulch around the plants, such as a mixture of compost, shredded leaves and manure, which insulates the soil, retains moisture and gradually releases nutrients in the soil. Replenish the flux since the organic materials decompose.
Supply the plants with 1 to 1 1/2 inches of water each week. Put a rain gauge in the ground around plants so you know if you need to water the plants. Put on the water evenly around the plants so all the roots have equal access into the water source. Avoid watering directly onto the plant because water can pool up in the leaves. Regular, steady watering is important to prevent cabbage heads from growing too quickly and splitting, a result of getting too much water after a period of drought.
Remove the weeds around the cabbage plants consistently. You can pull weeds by hand if there are just a few weeds, but a garden hoe makes it a lot easier to clear a large area of weeds, while also keeping the dirt loose. If you use a hoe, move carefully so you do not disturb the cabbage roots.
Inspect the leaves and dirt around the plants consistently for cabbageworms, which will eat holes through the leaves. Remove these tiny green bugs immediately so they do not destroy your harvest.
Apply fertilizer to the plants when the cabbage heads start to develop, choosing either a complete, water-soluble fertilizer or an organic fertilizer such as fish emulsion. Mix the water-soluble fertilizer in the water supply for easy, even application.
Cut cabbage heads in the stem with a sharp knife when they reach the size of a softball. Peel away the outer leaves and discard. You can harvest fall crops when they grow beyond softball size, if desired, because you don’t need to think about hot summer temperatures damaging the cabbage.