Growing cauliflower (Brassica oleracea) is a little more challenging and labor-intensive than some other garden vegetables, but adding this versatile vegetable to your menu will be worth all the extra time. Whether you stick with a white variety, like Snowball Y or Snow King, or opt for the more exotic purple Graffiti, lime-green Romanesco with its pointed head, or orange Cheddar, your cabbage-cousin will thrive in a cool-temperature garden.
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Sun and Soil Requirements
Cauliflower loves fertile, well-drained loamy soil with a pH level of 6.0 to 7.0. Prepare your planting area by tilling the soil 12 to 15 inches down and then mix well-cured compost to a 6-inch depth. Situate your cauliflower bed to ensure six hours of full sun daily. Plant about three weeks before the last frost for spring gardens or about seven weeks before the first frost for fall crops.
Spacing and Depth Needs
Transplant seedlings when they have five leaves, planting them 18 to 24 inches apart in rows spaced about 3 feet apart. Cover the bed with a 3-inch layer of mulch to maintain soil moisture and temperature level. If you are direct-seeding, place the seeds about 1/2 inch deep.
Water and Feeding Requirements
Cauliflower needs a steady supply of both water and nutrients, so be sure that your plants receive 1 to 1 1/2 inches of water each week, including rainfall. Feed your veggies every month with fish emulsion or compost tea. To make the tea, mix 1 pound of aged compost and 1 gallon of water. Stir the mix each day. After five days, strain the results through cheesecloth and apply it to the garden. Stop using the tea three weeks before you plan to harvest.
Pest and Disease Control
While cauliflower is fairly hardy, it can be vulnerable to clubroot and similar diseases. The best control for these problems includes crop rotation and disease-resistant cultivars, along with strong garden sanitation. Keep flea beetles away from your cauliflower with floating row covers and remove aphids with a blast of water from the hose. Cabbage loopers may require a little more effort. Hand-pick the larvae when you see them and encourage Trichogramma wasps to call your garden home. If that doesn’t do the trick, you can apply a solution of Bacillus theringiensus as a last resort. Mix about 2 teaspoons of the bacillum to 1 gallon of water and spritz it on actively feeding loopers.
Special Considerations and Requirements
For bright white heads, you need to blanch the cauliflower. To do this, when the head is about the size of an egg -- about 2 inches in diameter -- pull the leaves of the plant over the head and use clothespins to hold the leaves in place. Also, avoid stress on the plants by disturbing the roots when weeding, giving too much or too little water or putting other strain on the growing vegetables to prevent “buttoning,” or premature formation of tiny heads.