Cool-Season Vegetable

When to Plant Cauliflower in New Hampshire

The diva of the brassica family. More temperamental than broccoli but worth the extra attention.

The Short Answer

Cauliflower are cold-tolerant and do well in New Hampshire's varied climate. New Hampshire gardeners can also plant a fall crop. Rocky, acidic New England soils. Glacial deposits. Granite bedrock. Raised beds essential in many...

New Hampshire Frost Dates

Your planting dates depend on which part of New Hampshire you're in. Here are the frost date ranges by region:

Region	Zones	Last Frost (Spring)	First Frost (Fall)
Northern New Hampshire	3b, 4a, 4b	May 20 - Jun 5	Sep 10 - Sep 25
Southern New Hampshire	5a, 5b, 6a	May 1 - May 20	Sep 25 - Oct 10

Cauliflower Planting Schedule for New Hampshire

Northern New Hampshire (Zones 3b, 4a, 4b)

Average last frost: May 20 - Jun 5 · Average first frost: Sep 10 - Sep 25

Start Seeds Indoors

6 wks before frost

Transplant Outside

2 wks before frost

Fall Planting

10 wks before first frost

Southern New Hampshire (Zones 5a, 5b, 6a)

Average last frost: May 1 - May 20 · Average first frost: Sep 25 - Oct 10

Start Seeds Indoors

6 wks before frost

Transplant Outside

2 wks before frost

Fall Planting

10 wks before first frost

Growing Cauliflower in New Hampshire

Cauliflower in New Hampshire's Climate

Cauliflower is more demanding than broccoli — it needs steady 60-70°F temperatures during heading, which your unpredictable spring weather may not provide. Fall is the better season: start indoors in mid-June, transplant in mid-July, and let the gradual autumn cool-down produce tight, clean heads. Temperature swings cause buttoning (premature tiny heads).

Soil Considerations for New Hampshire

Rocky, acidic New England soils. Glacial deposits. Granite bedrock. Raised beds essential in many areas.

New Hampshire Climate & Growing Season

Short growing season especially in north. Cold winters. Cool summers. Hardy varieties important.

Growing season length varies across New Hampshire: Northern New Hampshire (3b, 4a, 4b) has a last frost around May 20 - Jun 5, while Southern New Hampshire (5a, 5b, 6a) sees frost end around May 1 - May 20. This difference matters for cauliflower — adjust your planting dates to match your specific region.

Growing Tips

Blanch white varieties by tying outer leaves over the head when it reaches 2 inches. Temperature swings cause buttoning.

Companion Planting

Plant cauliflower alongside these companions for better growth:

Beets Celery Onions

Keep cauliflower away from:

Strawberries Tomatoes

The Bottom Line

Cauliflower can be grown successfully across New Hampshire, but your exact planting dates depend on which region you're in. Northern New Hampshire gardeners should plan around a May 20 - Jun 5 last frost, while those in Southern New Hampshire can typically plant earlier. For exact dates based on your zip code, use our free planting date finder.

Note: All dates are based on NOAA 30-year Climate Normals and represent historical averages, not predictions for any specific year. Always check your local weather forecast before planting frost-sensitive crops. Learn about our data sources.

Last reviewed: March 29, 2026