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When to Plant Cauliflower in Haines Borough, AK

Cauliflower is a cool-season brassica that produces dense white, purple, or green heads called curds. It is more finicky than broccoli but rewards with a mild, nutty flavor.

Haines Borough, Alaska is in USDA Zone 6a. The average last spring frost is May 7 and the first fall frost is September 29, giving you a growing season of approximately 145 days.

At an elevation of 1,921 feet, Haines Borough receives approximately 57.3 inches of rainfall annually with predominantly silt loam soil. Summer highs average 68ยฐF, so choose short-season varieties of Cauliflower to ensure they mature before fall. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Cauliflower root diseases.

Haines Borough, AK (Zone 6a) Short season
145 days
Last Spring Frost May 7
145 growing days
First Fall Frost September 29

Haines Borough Soil Profile

Soil Type

Silt Loam

Soil pH

4.9-6.4

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (27 days to spare)
Start indoors: Mar 24 Transplant: Apr 28 🍅 Harvest: Jun 23 – Aug 25
Recommended (50%) ✓ Fits season (26 days to spare)
Start indoors: Apr 2 Transplant: May 7 🍅 Harvest: Jul 2 – Sep 3
Safe Start (90%) ✓ Fits season (24 days to spare)
Start indoors: Apr 23 Transplant: May 28 🍅 Harvest: Jul 23 – Sep 24

Percentages indicate frost risk at transplant. The 70% safe window means there is a 30% chance of frost after transplant — suitable for cold-hardy crops or gardeners with frost protection. The 90% safe window is best for tender plants.

Plant Water Budget

Plant needs
1.5″/week
Rainfall provides
1.7″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft
Cauliflower needs ~78 GDD — county provides 145 GDD Excellent fit

Cauliflower Planting Timeline โ€” Haines Borough, AK

Cauliflower Planting Calendar

Activity When Date Range
Start Indoors April 2 Apr 2 โ€“ Apr 16
Transplant Outdoors May 7 May 7 โ€“ May 21
Direct Sow April 23 Apr 23 โ€“ May 14
Fall Sowing July 21 Jul 21 โ€“ Aug 4
Harvest July 2 Jul 2 โ€“ Sep 3

Plant 1" deep ยท 15" apart ยท Rows 24" apart

Month-by-Month Timeline

MonthActivities
January โ€”
February โ€”
March โ€”
April Start Indoors Direct Sow
May Transplant Outdoors Direct Sow
June โ€”
July Fall Sowing Harvest
August Fall Sowing Harvest
September Harvest
October โ€”
November โ€”
December โ€”

Growing Conditions

Sun

Full Sun (6-8+ hours)

Water

High โ€” keep soil consistently moist

Days to Maturity

55โ€“100 days

Soil pH

6 โ€“ 7

USDA Zone

Zone 6a

Growing Season

145 days

Growing Tips for Haines Borough

Start seeds indoors 6 weeks before transplanting. Blanch white varieties by tying outer leaves over the head. Provide consistent moisture and avoid temperature extremes.

Companion Planting

Good Companions

Avoid Planting Near

  • Tomatoes
  • Strawberries

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Frequently Asked Questions

When should I plant Cauliflower in Haines Borough, AK?

Haines Borough is in Zone 6a with an average last frost of May 7. Plan your Cauliflower planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Haines Borough, AK?

Haines Borough, Alaska is in USDA Hardiness Zone 6a. The average last spring frost is May 7 and first fall frost is September 29.

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Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Haines Borough gardeners in Zone 6a organize planting dates, track what's growing, and never miss a planting window.

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Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for Haines Borough, AK. Local conditions may vary. Last updated: April 2026.