Gardening Help FAQs

Here are answers to some of the most common questions we receive about garden plants. You will find concise information on general gardening techniques as well as plant selection and care. For detailed information on specific plant pests and problems refer to our Common Garden Pests and Problems page.

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Horticulture Questions and Answers

How do I grow cabbage, broccoli, and cauliflower?

Cabbage, cauliflower, broccoli and brussels sprouts are closely related plants that require similar growing conditions. They are all from the cabbage family and are commonly referred to as cole crops. With the exception of cauliflower, which is quite sensitive to cold in the early spring, these crops are very hardy and can withstand light frost. Cauliflower is also sensitive to summer heat. Transplants can be set out between March 20 and the middle of April. These crops prefer cool moist spring weather but if spring warm up is slow delay planting a week or so.

All of these crops can be started from seeds sown indoors about 6 weeks before planting in the garden. Germinate and grow under cool conditions. A sunny window or under fluorescent lights in a cool room or basement are good location for growing these transplants. Seeds can also be sown directly in the garden but harvest will be delayed. For a fall crop sow seeds around June 15th or set out plants around August 1st.

When the soil is dry enough to work without forming clods, spade the soil and incorporate 1-2 inches of organic matter and fertilizer as specified by a soil test. If you have not had a soil test you will have to guess at your fertilizer needs. A one pound coffee can measure of a complete fertilizer like 5-10-10 per 100 feet is a standard recommendation but since many urban gardens often have adequate phosphorus and potassium you may only need to add nitrogen. Only a soil test can give you this information. For information on soil testing listen to Hortline message "Soil Sampling and Testing".

Do not plant these crops too deeply. Plant so the root ball is covered by only 1/2 to one inch of soil. Do not bury the stems of leggy plants like you would leggy tomatoes. Space broccoli, brussels sprouts and cauliflower 18 to 24 inches apart. Cabbage can be planted a bit closer, 12 inches for early varieties and 18 inches for late varieties. Place a 2 inch collar of light cardboard around the stem of each plant as a barrier to cutworms.

As soon as cauliflower flower heads begin to form they should be covered to keep them white. Use a large cabbage leaf to shade out the light or gather the cauliflower leaves together and tie them loosely above the growing flower head.

Cole crops are very attractive to the imported cabbageworm, cabbage looper and aphids. Aphids are soft bodied insects usually found on the under side of leaves or in the center of the plant. They are often seen on transplants. They are piercing sucking insects which feed on the plant's sap. They can be controlled by the use of insecticidal soap sprays which are non toxic to humans and pets or with the insecticide Malathion. The imported cabbageworm and cabbage looper chew ragged holes in the leaves. Severely affected plants can be stripped to their veins! Control is by hand picking or by spraying. Bacillus thuringiensis, often called BT, is a biological control that is non-toxic to humans and pets. The insecticide Sevin is also very effective in controlling these pests. Read and follow all label directions before using pesticides. Many pesticides require a waiting period between application and harvest.