Cauliflower
What Plant Yet? knows about cauliflower, and where each number comes from. For today's answer, pick your town.
Planting numbers
- Frost category
- Semi-hardy Source: Colorado State University Extension
- Plant outdoors
- From 2 weeks before typical last frost up to the frost date Given for semi-hardy crops as a group. Source: Colorado State University Extension
- Start seeds indoors
- 6–8 weeks before typical last frost Source: Colorado State University Extension
- Cover at or below
- 28°F Source: Oregon State University Extension
- Grows once daytime temperatures reach
- 40°F Given for semi-hardy crops as a group. Source: Colorado State University Extension
- Days to harvest
- 55–80 Source: Iowa State University Extension
Left out because we found no university extension source for it: minimum night temperature. We don't estimate.
Growing tips
- Summer heat and long days discolor the curds red-purple. (Colorado State University Extension)
- Avoid early stress (cold, drought, low nitrogen, transplant shock) or heads stay button-sized. (Colorado State University Extension)
- For the best-quality crop on the Front Range, direct-seed in early July for fall harvest. (Colorado State University Extension)
- Both freezing (32°F) and heat above 80°F reduce growth and head quality. (Utah State University Extension)
- Handle transplants gently and protect the growing tip from cold and cutworms. (Colorado State University Extension)
How the answer uses this
The planting window opens 2 weeks before typical last frost up to the frost date in your town and stays open while a planting still has 80 days to mature before the typical first fall frost. Inside the window the answer is Plant when the coldest of the next 7 nights stays above 28°F (no source gives a minimum night temperature, so the cold-damage temperature is used). Cover tonight shows when tonight's low is 28°F or colder while cauliflower is normally in the ground.
Sources
- Colorado State University Extension — checked Nov 11, 2026
- Colorado State University Extension — checked Nov 11, 2026
- Oregon State University Extension — checked Nov 11, 2026
- Iowa State University Extension — checked Nov 11, 2026
- Colorado State University Extension — checked Nov 11, 2026
- Utah State University Extension — checked Nov 11, 2026
Guidance only. Extension advice is written for typical conditions; your soil, variety and microclimate matter.