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When to Plant Cauliflower in Jackson County, OR

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.

Jackson County, Oregon is in USDA Zone 8a. The average last spring frost is May 7 and the first fall frost is October 10, giving you a growing season of approximately 156 days.

At an elevation of 422 feet, Jackson County receives approximately 46 inches of rainfall annually with predominantly silt loam soil. Summer highs average 88ยฐF, providing good warmth for Cauliflower during the growing season.

Jackson County, OR (Zone 8a) Moderate season
156 days
Last Spring Frost May 7
156 growing days
First Fall Frost October 10

Jackson County Soil Profile

Soil Type

Silt Loam

Soil pH

5.3-6.4

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (40 days to spare)
Start indoors: Mar 22 Transplant: Apr 26 🍅 Harvest: Jun 21 – Aug 23
Recommended (50%) ✓ Fits season (37 days to spare)
Start indoors: Apr 2 Transplant: May 7 🍅 Harvest: Jul 2 – Sep 3
Safe Start (90%) ✓ Fits season (41 days to spare)
Start indoors: Apr 28 Transplant: Jun 2 🍅 Harvest: Jul 28 – Sep 29

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
1.2″/week
You supply
0.7″/week
Watering frequency 2-3 times/week
Season total 988 gal / 100 sq ft
Cauliflower needs ~1,240 GDD — county provides 2,496 GDD Excellent fit

Cauliflower Planting Timeline โ€” Jackson County, OR

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 August 1 Aug 1 โ€“ Aug 15
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 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 8a

Growing Season

156 days

Growing Tips for Jackson County

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 Jackson County, OR?

Jackson County is in Zone 8a 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 Jackson County, OR?

Jackson County, Oregon is in USDA Hardiness Zone 8a. The average last spring frost is May 7 and first fall frost is October 10.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Jackson County gardeners in Zone 8a 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 Jackson County, OR. Local conditions may vary. Last updated: April 2026.