Starting Your Seedlings
For early spring planting, you should start your seedlings six to eight weeks before the last frost date in your area.
Use a rich, balanced, sandy or loamy potting soil with a pH of 6.5 to 6.8 that has been blended specifically for vegetables or vegetables and herbs. Gardening soil is too heavy for use in containers and could contain eggs from pests, seeds from weeds, and disease.
You should space your seeds 2 inches apart and cover them with 1/4 inch of soil.
Water your cabbage evenly, but avoid overwatering that leaves the soil soggy or that leaves water standing in the containers.
Place your seeds in a sunny location or under a grow light or a cool white florescent light in an area where the temperature remains between 65-75°F (18-24°C) to encourage germination.
Preparing Your Seedlings for Transplanting
You can transplant your seedlings two to three weeks before the last frost date for your area. About one to two weeks before you intend to transplant your seedlings, you should begin hardening them, or acclimating them to the conditions outside:
- On the first day of hardening, bring your seedlings outside for about two hours on a cloudy afternoon.
- On the second day, set your seedlings out in the morning sun for about an hour and extend the time you leave your cabbage outside to four hours.
- From the third day on, gradually continue to extend the time you leave your cabbage outdoors and in the morning sun.
Eventually, you can begin leaving your cabbage outdoors overnight when no hard killing frost is expected.
Spacing Your Transplanted Cabbage Seedlings
The spacing of your seedlings determines how large of a head your cabbages will form. For your first spring planting, you might want to space your seedlings 6 inches apart in rows that are 12-24 inches apart. Then, you can harvest every other head and enjoy the smaller heads while the remaining heads grow to 12 inches.
If you want larger heads, wait until your seedlings have grown to 5 inches tall, and then thin your cabbages to 18-24 inches apart. Replant the thinned out cabbages in another area of your garden.
Instead of planting your cabbage in traditional rows, you can save space by planting one seedling on the row line, measuring 10-12 down the row, and then planting two cabbages 5-6 inches to each side of the row line. Continue alternating this pattern of one cabbage followed by two cabbages along the rest of the row.
Another space saving pattern is to plant three cabbages at one end of the row followed by two cabbages, and repeat that pattern to the opposite end of the row.