Cauliflower can be a tricky crop to grow, especially for southern gardeners. A member of the cabbage or brassica family, cauliflower thrives in the cool temperatures of spring and fall. While cauliflower may survive light frosts, it isn’t winter hardy, so growing it in much of the Southeast means finding a sweet spot between temperatures that are too hot or too cold. These tips can help you grow finicky fall cauliflower with success.
When to Plant Fall Cauliflower
Southern gardeners can grow cauliflower anytime the weather is consistently cool and they can avoid the risk of hard frosts. For those in the Deep South, cauliflower may be a good winter crop.
Cauliflower is highly sensitive to temperature. It grows best when the temperature is consistently between 60° and 65°F. If the temperature is too hot, cauliflower will form stunted heads and bolt, or go to flower prematurely. Wait to plant cauliflower outdoors until temperatures are consistently below 75°F.
You also want to plant your cauliflower early enough that you can harvest the heads before it gets too cold. Cauliflower can tolerate light frosts, but prolonged exposure to temperatures below 32°F will damage the curds, making them rubbery.
Days to maturity can vary for cauliflower depending on the variety you select, when you plant, and the weather. For fall-planted crops, we recommend adding 15 days to your cauliflower variety’s expected ‘days to harvest’ to account for dwindling fall light. Those days should begin when you transplant the cauliflower out into the garden, not when you start seeds indoors.
Start Your Cauliflower Indoors
While you can direct-sow cauliflower, for fall gardens its best to start your plants indoors. Even if the weather is still too hot for cauliflower to germinate and grow, you can get the plants started in a cool spot indoors.
Cauliflower can get leggy and weak without adequate light. Most growers will find they need supplemental lighting to start cauliflower and other plants indoors.
Read more about starting transplants indoors here.
Soil Preparation
Cauliflower can also be picky about its soil requirements. If possible, have your soil tested. Cauliflower thrives in fertile soil with a pH between 6 and 7.
For good production, cauliflower needs consistent nutrients throughout its growing period. Amend your soil with finished compost or aged manure before planting. Fertilize with a well-balanced fertilizer if necessary.
Transplanting Cauliflower
After hardening off, transplant your cauliflower seedlings out into the bed on a cool, overcast day. Cauliflower needs plenty of space as it matures, so plant it 18 to 24 inches apart in rows 30 inches apart.
Watering, Weeding, and Care
Cauliflower requires consistent moisture throughout its growth period to produce firm, nicely flavored heads. Cauliflower plants that experience drought can develop off-flavors or a mushier texture. Water consistently if you’re not getting at least one inch of rain per week, especially if you have sandy soil, which drains more quickly.
Ensuring your plants aren’t competing with weeds will also help your cauliflower develop. Weed frequently using a hoe to kill small weeds, but be careful not to damage the plants. Using mulch can also help reduce weeds and keep the soil cool and moist.
Cauliflower Pests & Diseases
Unfortunately, cauliflower is susceptible to several pests and diseases, including cabbage worms, flea beetles, black rot, and downy mildew. Cabbage worms, also called cabbage moths or cabbage loopers, are what we most frequently see gardeners struggling with, and they can be particularly troublesome in the fall after breeding all summer.
To conquer the cabbage worms, visit our guide to organic cabbage worm control.
Blanching Cauliflower
If you want white cauliflower, you need to blanch the curds. When the white head or curd begins to form, tie the top leaves together over it to protect the curd from sunlight, which causes the curd to yellow.
Don’t do this for purple or yellow cauliflower or romanesco! They need the light to develop full color.
Harvesting Cauliflower
Cut your cauliflower heads when they are large and firm. If you leave them too long, the curds will become loose and open, and they will lose flavor. Usually, this is slower in the cool temperatures of fall and winter. Don’t harvest when heads are wet, or the curds will mold in storage.
Cauliflower heads will typically last a week or two in the refrigerator when harvested properly. You can also blanch and freeze cauliflower for later use.
