By Sommer Cartier.
Cauliflower is a cool season crop widely loved for its beautiful, tight, white curds and its mild nutty flavor. However, cultivating this plant can be a challenge; even the most experienced gardeners can find themselves discouraged. Two of the most common obstacles to growing this brassica in San Diego’s semi-arid Mediterranean climate are insect damage and buttoning of the heads (tiny head formation).
Insect Damage
Aphid infestations are common and result in shriveled leaves and underdeveloped heads. As with all pests and disease, prevention starts with healthy, nutritious soil. Like humans, plants are more equipped to fight disease and pests when they are strong, healthy, and getting ample nutrients. Make sure your soil is rich with nutrient-dense organic matter and beneficial micro-organisms like earthworms, or what I like to call the “underground farmers."
It’s equally important to incorporate plants that attract beneficial insects such as lady bugs, lace wings, and parasitic wasps. These friendly critters help maintain a balanced population of insects. Plant flowering herbs such as dill, fennel, and coriander. Sweet alyssum, lemon balm, and lavender are great as well.
If your cauliflower falls victim to aphids, try the following strategies:
1. Start with the least invasive method—spray the aphids off with a hose.
2. If aphids continue to return, take a more aggressive approach and spray with a homemade soapy water solution. Simply mix a tablespoon of liquid soap with a gallon of water and pour into a spray bottle. Thoroughly spray the plant with the soapy water making sure you get those hard to reach spots under the leaves and in the crevices surrounding the cauliflower heads. Be aware of bugs hiding in curled leaves. Repeat this process every four to seven days until the aphids are gone. Just remember: soapy water kills soft body insects, including beneficials. For this reason, it’s critical that you take an integrated approach to treating pests.
Buttoning of Heads
There are several causes for tiny head formations, and most are environmental. In San Diego, this head buttoning tends to occur during heat waves. Too much heat (temperatures over 80 degrees) prevents cauliflower heads from fully forming. Cauliflower does best in continuous growing conditions from seed to harvest. Environmental stressors, whether they be excessive heat or cold, pests, or insufficient water, may result in tiny head formations. Wherever possible, plant cauliflower in cooler parts of the garden where they receive six hours of direct sunlight. If your garden has full sun exposure, utilize shade cloth to protect your cauliflower.
Follow these tips and you will enjoy a healthy bounty of beautiful, pearly white cauliflower heads this winter.