In the spring about five to seven weeks before the last frost date.
How to Grow Cabbage. When growing cabbage, be sure to space the plants 12 to 24 inches apart. The closer you space your cabbage plants, the smaller the head of the cabbage will be. Early varieties of cabbage can be planted 12 inches apart and will grow one to three pound heads. The later varieties can produce heads upwards of eight pounds. Once you learn how to grow cabbage, you will have a great cabbage crop. Make sure to sow the cabbage seeds ¼ to ½ inch deep Spring plants should produce before the heat of the summer and can be planted 4 weeks before the last frost. Fall cabbage is best to be in the ground 6 to 8 weeks before the first frost. You should also try to plant the seedlings on a cloudy or overcast day to minimize the shock of transplanting. Ad. You can leave the rest of the cabbage plant and harvest a later batch of cabbage sprouts, which will be 2 to 4 inches (5.1 to 10.2 cm) in diameter. Cabbage heads can be placed in the refrigerator for up to 2 weeks if covered loosely with a plastic bag. Cabbage seeds should typically be started indoors in the spring, about five to seven weeks before the last frost date predicted for your area. Plants started in April or May can be moved outside in about four to six weeks. Transplant the cabbage seedlings outside as soon as they have three real leaves. This may be as early as a couple of weeks before the last expected frost. If daytime temperatures consistently reach a high of 50 degrees F, your cabbage plants will be fine. Planting Cabbage. When planting cabbage, it's usually best to transplant seedlings into your garden. If you want to start with seeds, plant them indoors in small containers or flats. Once the seedlings reach 3 inches tall, they can be transplanted into your garden. You can also purchase cabbage seedlings at most garden centers.  Cabbage seed can be direct sown in the garden but this is not the typical method. Early varieties are started indoors, four to six weeks prior to your last expected frost date. Two weeks before transplanting into the garden, the seedlings should be hardened off to acclimate the tender plants to the conditions outdoors.  When to Plant Cabbage. In spring, start seeds indoors or in a cold frame eight to 10 weeks before your last spring frost, and set out hardened-off seedlings when they are about 6 weeks old. Seeds germinate best at 65 to 75 degrees Fahrenheit. In summer, start seeds 12 to 14 weeks before your first fall frost, and transplant the seedlings to the garden when they are 4 to 6 weeks old. Plant early and late varieties to stretch your harvest season. You can get seed from a head of cabbage if you grow it yourself. It is a biennial vegetable so it will grow the head the first year and if you leave it in the ground over the winter it will sprout seed heads the next year. You can buy seeds to plant or you can also find seedlings to transplant at garden centers.  1 Once the seeds have germinated, thin the seedlings to 7.5cm (3in) between each plant. 2  Cabbage and broccoli seedlings are ready for transplanting when they're between 6 and 8cm high (2.5-3in). 3  Brussels sprouts and kale should be 15cm (6in).Water the day before moving, and keep well watered until established. Seeds should be sown thinly, as this reduces the amount of future thinning necessary and potential risk from pests. 1  Sow seeds 1.25cm (1/2in) deep and rows should be spaced 15cm (6in) apart. 2  Cabbage seeds can be planted in the garden in the spring and fall. If you want to give the cabbage plants a head start in the spring, start them inside. Plant the seeds indoors about 6 weeks before you want to transplant the seedlings into the garden. In the fall you can plant the cabbage seeds directly into the garden. After the seeds germinate and begin to grow, thin them so the growing cabbage has enough room to grow. Plant your fall crop of cabbage at least 70 days before the weather gets too cold.
http://www.gardeningknowhow.com/edible/vegetables/cabbage/growing-cabbage.htm http://www.wikihow.com/Plant-Cabbage http://www.gardenguides.com/101029-cabbage-seeds-sprout-indoors.html http://www.backyard-vegetable-gardening.com/planting-cabbage.html http://www.victoryseeds.com/cabbage.html http://www.motherearthnews.com/organic-gardening/vegetables/growing-cabbage-zm0z12aszkon.aspx http://www.almanac.com/plant/cabbage http://www.bbc.co.uk/gardening/basics/techniques/growfruitandveg_growingbrassicas1.shtml http://www.provident-living-today.com/Growing-Cabbage.html
when should cabbage seeds be planted