Broccoli and cauliflower are two popular garden vegetables belonging to the cabbage or cole family. Other commonly grown cole crops include brussels sprouts, collards, kale, kohlrabi, and cabbage. These vegetables go a long way to add variety and nutrition to the family diet.
Cole crops are cool weather vegetables, growing best when daytime temperatures are between 65 and 80 F. Cauliflower is more sensitive to hot weather than broccoli. In Ohio, broccoli is grown as a spring and fall crop, while cauliflower does best when planted in mid-summer for a fall harvest. Both broccoli and cauliflower do best when set out as transplants rather than planted from seed. It is important to use sturdy transplants and that they become established quickly or the plants may not develop properly.
All of the cole crops grow well in reasonably fertile, well-drained, moist soils with plenty of added organic matter. A mulch will help keep the ground cool and moist. The pH should be between 6.0 and 7.0 for optimum growth. A pH within this range will discourage clubroot disease and maximize nutrient availability.
Fertilizer and lime are best applied using the results of a soil test as a guide. Contact your local Cooperative Extension office for information on soil testing. In the absence of a soil test, 2 to 3 pounds of 8-16-16 fertilizer applied uniformly over 100 square feet of garden area is suggested. Work the fertilizer thoroughly into the soil about two weeks before planting time.
A liquid starter fertilizer applied to the transplants at time of planting will help get them off to a good start. Apply a half pint of a 20-20-20 or similar solution to each plant, preparing the fertilizer according to label directions.
For good side shoot production after harvest of the main head, try Green Comet and Packman. Two other excellent cultivars for the home garden are Green Hornet and Premium Crop.
Snow Crown, Snow King, Snowball 123, and Imperial 10-6 are good cultivars for the home garden. Also, try Self-Blanche using a 12-inch spacing for support and effective blanching. Violet Queen is a purple-headed cultivar that does not require blanching.
All cole crops are frost tolerant. Broccoli transplants may be set out in the garden as early as April 1st. For a fall cauliflower crop, set out transplants on July 1st. Broccoli may be spaced 18 inches apart in the row with 24 inches between rows. Cauliflower requires a little more room. Set cauliflower plants 24 inches apart in the row with 30 inches between rows.
As cauliflower plants begin to mature and the head or curd starts to form, gather together and tie the leaves over the curd with soft twine or tape. This “blanching” is required to ensure the curd will be white and tender at harvest. There are some ‘self-blanching’ types available where the leaves curl naturally over the head when grown in cool weather. However, some tying of the leaves may still be necessary.
An even moisture supply is needed for transplants to become established and to produce good heads. As mentioned earlier, an organic mulch will help keep soils cool and moist, and suppress weed growth. Hand-pull or use shallow cultivation if additional weed control becomes necessary. Apply 1 to 1.5 inches of water per week if an equal amount of rainfall does not occur. An additional side dressing of a nitrogen fertilizer when the plants are well-established may be desirable.
Principle insect and disease problems are the cabbage looper and imported cabbage worm, cabbage root maggot, aphids, flea beetles, blackleg, black rot, clubroot, and yellows. Contact your local Cooperative Extension office for identification and current control recommendations.
Harvesting and Handling
Harvest the center green flower bud cluster of broccoli while the buds are still tight and before any yellow petals begin to show. Cut the central stem five to six inches below the head. Many cultivars will continue producing bonus side shoots as long as a few leaves are left on the plant. This can extend the harvest period for a month or more. Green Comet, an All-American Selection, is a good producer of side shoots.
The cauliflower curd, like the broccoli head, is actually a group of tightly clustered white or purple flower buds. Harvest the curd when it reaches the desired size but before the buds begin to separate. This is about two months after transplanting. Cut the head so that at least two wrapper leaves are present.
Source: OSU Ext., Marianne Riofrio