Zone 6 · Brassicas Growing Guide

When to Plant Cauliflower
in Zone 6

The most demanding brassica. Needs consistent temperatures — too hot or too cold and the head won't form. 'Blanching' (tying leaves over the head) keeps it white. Rewarding when it works.

Plant outdoors
Mar 15 – Apr 15, Aug 1 – Sep 1
Start indoors
Feb 10 – Mar 1
Last Frost
~Apr 1
Days to harvest
75–100 days
Difficulty
Hard
Growing — Zone 6
Harvest window: May – Jun, Oct – Dec

Planting Calendar

In Zone 6, Cauliflower should be planted outdoors Mar 15 – Apr 15, Aug 1 – Sep 1, after the average last frost date of approximately Apr 1. Start seeds indoors around Feb 10 – Mar 1 for a head start.

Fall crop is most reliable in Zone 6. Consistent temperatures make better heads.

Care Guide

Sunlight
Full sun · 6–8 hrs/day
Watering
Regular
Spacing
18–24 inches
Soil
Rich, fertile, well-draining
Days to maturity
75–100 days
Soil pH
6.0–7.0
plant tip · Zone 6

Fall crop is most reliable in Zone 6. Consistent temperatures make better heads.

Feeding Schedule

How often
monthly
Feed type
high nitrogen then balanced
Key timing
switch to balanced when curds form

Same as broccoli — nitrogen early, balanced once the head appears. Consistent moisture matters more than feeding.

Succession Planting

Sow every 4 weeks

Start a spring crop and a late-summer crop for autumn harvest. Cauliflower is tricky — succession helps spread risk as individual plants often fail.

Companion Planting for Cauliflower

What you plant next to cauliflower makes a real difference — some plants actively help, others compete or attract pests.

Grows well with
  • Celery
  • Onions
  • Hyssop
  • Spinach
Keep away from
  • Tomatoes
  • Strawberries
  • Beans
  • Fennel

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Common questions

In Zone 6, cauliflower has two planting windows: Mar 15 – Apr 15, Aug 1 – Sep 1. The spring window opens after your last frost around Apr 1. The fall window lets you grow a second crop before first frost around Oct 31. Fall crop is most reliable in Zone 6. Consistent temperatures make better heads.
Zone 6 has an average last spring frost of approximately Apr 1 and a first fall frost around Oct 31. These dates vary by specific location — use your ZIP code in the plant app for precision based on the nearest NOAA weather station.
Good companion crops for cauliflower include Celery, Onions, Hyssop, Spinach. Avoid planting near Tomatoes, Strawberries, Beans, Fennel, which can compete for nutrients or attract pests.
Cauliflower typically takes 75–100 days from transplant or direct sow to harvest in Zone 6. Expected harvest window: May – Jun, Oct – Dec.

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Cauliflower in other zones
Crop Guides