Cauliflower planting guide
When to start cauliflower seeds
Start cauliflower about five weeks before a suitable transplant date: roughly four weeks of seedling growth and about one week of hardening. Choose the outdoor date for cool head-forming weather.
Transplant lead time
About 5 weeks
Allow about four weeks indoors and one week to harden.
Best head development
50-70°F
Cool conditions support dense, good-quality heads.
Rotation interval
4 years
Avoid beds recently used by related cabbage-family crops.
Season choice
Variety matters
Fast, heat-tolerant types are better candidates for spring.
Seed-starting calculator
Find when to start seeds indoors
We count backward from the outdoor planting date using university timing guidance.
Seedling stage
Harden after about four weeks
The source says plants should have four or five true leaves after about four weeks. Reduce watering, then gradually expose them to more sunlight and wind over the next week.
Head formation
Aim for cool finishing weather
Dense cauliflower heads develop in cool conditions, with the source listing 50-70°F. A seed-starting date cannot predict whether the crop will reach that stage before heat or severe cold.
Variety and color change the care plan
Spring varieties
For spring, the source favors heat-tolerant varieties with a short 50-60 day growth cycle so heads form before sustained summer heat.
White heads
White cauliflower may need blanching, which means shielding the developing head from sunlight. Follow the variety directions.
Colored heads
Green, orange and purple types need sunlight to develop their color, so do not automatically use the white-cauliflower method.
Spring and fall are different plans
The Extension source provides Minnesota month examples for both seasons. This page keeps the transferable five-week transplant process and temperature guidance but does not turn those month examples into national dates.
A practical next step
Plan cauliflower with your local season
Cool-season crops may grow before the last spring frost or after summer heat fades. Use crop-specific soil and temperature guidance too.
- 1. Local dates
Find spring and fall frost dates
See historical 32°F freeze estimates and the matched NOAA station for your ZIP Code.
- 2. Season length
Estimate the frost-date growing window
Compare cautious, middle and less-cautious spring/fall date pairs.
- 3. Seed schedule
Count backward for indoor seed starting
Choose a suitable outdoor date for cauliflower, then use the reviewed crop-specific lead time to build a seed schedule.