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New Mexico State University

New Mexico State University

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Plant Cole Crops in Summer For High Quality Fall Crop

ALBUQUERQUE -- To avoid split cabbage heads, brown cauliflower curds and bitter broccoli florets, plant these cole crops in early July for fall harvest. In warm areas of New Mexico, planting these crops in the spring causes them to mature in hot weather, said a New Mexico State University horticulture specialist.

"For optimum quality, cole crops should be direct-seeded in the garden during early July so they mature in the fall," Dickerson said. "Cool weather in the fall will reduce respiration in the plants causing sugars to accumulate. Growth is also slower, so crops like cabbage and kohlrabi don't split."

Before planting, it is important to prepare the seed bed with plenty of organic matter and a balanced fertilizer, he said. The distance between the plants will vary with the type of cole crop. Keeping the seeds moist with a drip irrigation system will ensure a good stand.

"Cole crops require a lot of nitrogen fertilizer," Dickerson said. "Since nitrogen fertilizers dissolve readily in water, most are applied in several split applications as the plants grow."

To apply the fertilizer, dig a trench with a hoe approximately two to three inches deep and about five to six inches away from the plants. Lightly scatter the nitrogen fertilizer in the trench and cover it with soil. Irrigate immediately so the fertilizer is dissolved and moved slowly to the feeder roots, he said.

"I like to plant to a stand using a hill system," Dickerson said. "Soil temperatures can be extremely hot in summer, so I plant the seed at least a half inch deep and cover it with vermiculite to reflect the sun and keep the seed cooler."

Two to three seeds in each hill will insure a stand as long as seeds are kept moist. Extra plants can be removed when the seedlings have at least two true leaves.

Dickerson recommends keeping an eye out for insects on developing seedlings this year. If seedlings look like they've been hit with birdshot, the problem may be flea beetles, he said. Later in the season, plants are often attacked by cabbage loopers, more commonly called the inch-worm.

An organic control for these worms is to spray or dust with a bacteria called Bacillus thuringensis (B.t.). Caterpillars will turn brown and die within a few days.