Surprise - Cauliflower Needs Good Soil
Organic Matter is Critical - As we have preached for years, the quality of the produce grown in the home vegetable garden is directly related to the health of the garden’s soil (Duhh). Most garden soils lack sufficient organic matter down 8 to 12 inches. Such material begins as organic mulch which is over the season broken down and pulled down into the soil by earthworms and other soil creatures. That is why we recommend having 2 to 4 inches of organic mulch on the surface of the garden all 365 days of the year. Check out yardener.com for advice on building up your gardens soil; click here.
Transplant Spring Cauliflower Seedlings Into Garden
In Spring Grow or Buy Seedlings? – Another issue that makes cauliflower somewhat more difficult is that to have any real choice in which variety you grow, you must raise your own seedlings indoors. If you buy your seedlings from the garden center, you might have two varieties from which to choose, while there may be ten or twelve varieties that are good for your region. While for many gardeners, that is part of the fun, for beginners growing seedlings from scratch can be a bit daunting. See our file “Growing Seedlings” for information about how to grow your own seedlings.
Cauliflower can be grown in the spring and/or in the fall, however in most parts of the country, the fall crop is more productive and less problematic. Cauliflower should be grown rapidly for best results. The weather will have a lot to do with how quickly it grows, but following the instructions in this file should lead to success.
Set out transplants two to three weeks before the last expected frost when the soil temperature is at least 50° F (10° C). Space seedlings 12 to 15 inches from any other plants. Young plants will withstand a light frost and mature plants can tolerate a moderate frost, but a severe frost may cause the plant to form a "button" instead of a full-sized head.
However, exposure of young plants to temperatures below 50°F can result in premature seed stalk development or failure to develop full-size heads. This can be a particular problem with cauliflower.
If you expect a serious (drop)in temperature, cover your cauliflower with fleece which will protect the plant six degrees lower than it would without the fleece. Just lay the light white polyspun material over the plants and hold down the material with stones or bricks. Keep the fleece on the plants until all threat of frost is gone.
Cauliflower In The Fall – Better Than The Spring Crop
You can grow cauliflower for a fall harvest with somewhat less concern than in the spring. The problem is figuring out when to start the seeds and when to put the seedlings out into the garden. The seed packet will give you the days to maturity. That works for the spring crop but not for the fall crop. Add two weeks to the number on the seed pack because days get shorter in the fall which extends the growing period. Plan on starting harvest in the first week in October. So you count back the days to maturity plus 14 and you have the date for starting seedlings; usually late June or early July. Set out seedlings when they are six to eight weeks old. Remember you have to harden off seedlings in summer just as you did in the spring – two or three days outside during the day and inside at night.
Fall cauliflower grow best between 60° and 70°F which come in September and October. Late varieties will continue to grow at fall temperatures as low as 41° F, but few varieties make much growth above 78°F. Cauliflower can withstand light frosts.
Shade Cloth Trick
One way to ease the effect of the heat of August and early September on your cauliflower seedlings is to shade them with shade cloth; material that will cut out 20% to 30% of the sun’s rays. Remove the shade cloth when the temps get below 70°F. See our section on using shade cloth in yardener.com; click here.