We got a question at Ask Gardenerd this week from Jeff: “I’m having trouble with cauliflower – the plants are not flowering. Is there anything I can do to encourage flowering? By the way, I planted broccoli as well and it’s doing fine. Thanks, Jeff”
You’re not alone, Jeff. This is typical of places that don’t have really cold temperatures in fall or winter. Cauliflower needs low temps to set a head, so in warm-winter climates you often get Jurassic leaves but no head. Warm-winter climates should grow cauliflower in the fall instead of spring. That may increase your chances if you haven’t tried that already. We grow Romanesco broccoli instead, since it has needs more similar to broccoli than cauliflower. If cold is not the issue, here are some other reasons why your cauliflower may not be flowering:
Nutrients – Cauliflower needs soil that is rich in nitrogen and potassium. Potassium is responsible for fruit and flower development and overall vigor. If your soil is lacking potassium (or it is locked up in the soil, which is more likely) your cauliflower won’t set a head. Some gardeners recommend applying fish emulsion every couple of weeks. We use kelp emulsion here and compost tea. A properly brewed batch of compost tea will be full of microbes that go to work to unlock trapped potassium in soils.
Water – according to Organic Gardening Magazine, cauliflower requires consistent moisture. The soil should never be allowed to dry out or you end up with “ricey” heads. So if you water regularly and mulch around your plants, you’ll retain moisture and prevent soils from drying out.
Variety – Explore cauliflower varieties that grow in your specific climate. Try purple cauliflower or Romanesco to see if they work better for you. We’re big fans of locally adapted seed, so check your seed library to see if anyone has contributed cauliflower seed for your neck of the woods. You’ll find more success by combining efforts with other gardeners in your area. If you don’t have a seed library, buy seeds from catalog companies that grow out seed in your hardiness zone or region. (Don’t forget to save the seeds if they are open pollinated varieties).
Don’t despair. Keep trying different approaches. Feed the soil first, then try adapted varieties and other cultivars that you haven’t experimented with yet. You’ll find the answer with persistence.
Thanks for writing in. And fellow Gardenerds – if you have suggestions for how you grow cauliflower, post your comments below.