Cabbage - Key Growing Information
SCIENTIFIC NAME: Brassica oleracea
CULTURE: Cabbage as well as cauliflower, Brussels sprouts, broccoli, and related brassicas are heavy feeders. They require fertile soils in a pH range of 6.5-7.5, supplied with consistent irrigation throughout the growing period.
EARLY SPRING CROP: Use early and midseason varieties. Sow 2 seeds per cell in 50- or 72-cell plug flats, 3-4 seeds/in. in 20-row flats, or in outdoor beds 1/4" deep. Seedlings should be ready to transplant in 4-6 weeks. If possible, keep soil temperature over 75°F (24°C) until germination, then reduce air temperature to about 60°F (16°C). Transplant outdoors, 4-6 weeks after sowing, 12-18" apart in rows 18-36" apart. Cabbage prefers cooler growing temperatures, between 55-75°F (13-24°C), optimum being 60-70°F (16-21°C), but will produce good crops under warmer, summer conditions.
FALL CROP: Use midseason and storage varieties. Start seedlings as above in May and transplant to the garden in June-July. To ensure mature heads, seed the crop early in areas where heavy freezes occur early in fall.
WINTER CROP: Successful cabbage crops can be grown where winters are mild (temperatures rarely below 32°F/0°C). Transplants can be set out from September to February in these regions.
DIRECT SEEDING: Sow 3-4 seeds 12" apart, 1/2" deep, rows 24-36" apart, thinning to one plant in each group.
SPLITTING: Early varieties may split or burst at maturity or from rapid new growth if rain or heavy irrigation follows a dry spell. Splitting may be partially avoided by slowing a plant's growth. To accomplish this, cultivate close to plants to sever some of the root system, or by slightly twisting the plant.
DISEASES: Adhere strictly to a preventive program including: (1) long crop rotations with non-brassica crops, (2) clean starting mixes and outdoor seedbeds, and (3) strict sanitation practices. Johnny's Selected Seeds only sells seed lots of cabbage that have tested negative for black rot (Xanthomonas campestris pv. campestris) and black leg (Phoma lingam).
INSECT PESTS: Repel flea beetles and root maggots on young seedlings by covering with floating row covers from day of planting. Treat flea beetles with insecticides such as pyrethrin or azadirachtin if heavy pressure is observed. For cabbage worms and loopers, use Bacillus thuringiensis (Bt). Cutworm prevention: Cultivate soil 2-4 weeks before planting to work in cover crops and destroy weeds.
HARVEST AND STORAGE: Relatively young heads (still green and actively growing) store best. Ideal conditions are 32°F (0°C), at 95-98% relative humidity, with good air circulation. Store only disease-free heads.
DAYS TO MATURITY: From cool weather, spring transplanting. Subtract 10-14 days for late spring or early summer, warm weather transplanting. Add about 14 days for direct seeding.
AVG. PRECISION SEEDING RATE: 100 seeds/50', 500 seeds/250', 1M/500', 29M/acre at 2 seeds/ft. with rows 36" apart.
SIZED SEEDS: "Sized" seeds have been sorted so they are roughly the same size. This consistency allows for more accurate spacing with mechanical seeders and more even germination. Cabbage seeds are sized, except when noted in the product description.
SEED SPECS: SEEDS/LB.: 67,500-164,300 (avg. 108,600).
PACKET: 100 seeds, unless otherwise noted.