Emmalea Ernest, Scientist – Vegetable & Fruit Crops; emmalea@udel.edu
Cauliflower is typically a fall crop in Delaware with transplants started in mid-July going into the field in mid-August. Fall plantings are subject to less heat stress during head development and therefore less likely to develop heat-related physiological disorders like curd separation (ricing), fuzziness, leaf formation in the head and purpling (Figure 1). However, some newer varieties are more heat tolerant and less prone to developing physiological disorders. To see how spring cauliflower might work in Delaware I planted a trial in 2020 at UD’s research farm in Georgetown, Delaware to test 18 white cauliflower varieties.
Figure 1. Cauliflower heads with curd separation, leafy heads and purple discoloration caused by heat stress
The transplants for the trial were seeded on March 4 and transplanted into bare ground on April 20. Some leftover transplants were used in a planting into white plastic mulch on May 1. Cauliflower matured and was harvested from June 15 to July 2.
Of the 18 varieties tested, three produced a high percentage of marketable heads in the April 20 transplanted trial: Bishop, Bermeo and Denali (Figure 2). Bishop and Bermeo have also been successful in all of my fall cauliflower trials and tend not to develop physiological disorders. If you decide to attempt a spring cauliflower planting, I’d recommend trying one or all of these three varieties.
Figure 2. Three cauliflower varieties that performed well in the spring 2020 cauliflower trial.
None of the varieties produced marketable heads when transplanted on May 1 onto white plastic, indicating that the window for planting spring cauliflower in Delaware is probably quite narrow and success will vary depending on our unpredictable spring weather conditions.