Yes, you CAN grow cole crops!
All cole crops are frost-tolerant, which makes them ideal for Rhode Island’s nippy nights in the spring. Broccoli transplants may be set out in the garden as early as April 15. For a fall cauliflower crop, set out transplants on July 1. Read on, and you’ll be enjoying your own cole crops this summer and fall!
Climatic Requirements
Cole crops are cool weather vegetables, growing best when daytime temperatures are between 65° and 75° F. Cauliflower is more sensitive to hot weather than broccoli. In Rhode Island, broccoli is grown as a spring and fall crop, while cauliflower does best when planted in early summer for a fall harvest. We highly recommend growing both broccoli and cauliflower by setting them out as transplants rather than planting from seed. At Confreda Greenhouses, we grow many varieties of cole crops that you can purchase for planting. They’re available now, so you can get your plants ready just in time for the season!
Soil Requirements
All cole crops grow well in fertile, well-drained, moist soil with plenty of added organic matter. Use mulch to keep the ground cool and moist. The soil pH should be between 6.0 and 7.0 for optimum growth, discouraging clubroot disease and maximizing nutrient availability.
Fertilizers
Work the fertilizer thoroughly into the soil about two weeks before planting time. Fertilizer and lime are best applied using the results of a soil test as a guide. (Hope you got your soil tested at Confreda last week!) In the absence of a soil test, we suggest applying 2 to 3 pounds of a balanced fertilizer over 100 square feet of garden area.
Planting Suggestions
It is important to use sturdy transplants and allow them to become established quickly, or the plants may not develop properly. An even moisture supply is needed for transplants to become established and to produce good heads.
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.
Hand-pull or use shallow cultivation if additional weed control becomes necessary. Apply 1-1 ½ inches of water per week if an equal amount of rainfall does not occur. An additional side dressing of a nitrogen fertilizer (organic or synthetic) may be desirable when the plants are well-established.
Principal insect and disease problems are the cabbage looper and imported cabbage worm, cabbage root maggot, aphids, flea beetles, blackleg, black rot and clubroot.
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.
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.
