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When to Plant Cauliflower in Jefferson County, PA

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.

Jefferson County, Pennsylvania is in USDA Zone 5a. The average last spring frost is May 18 and the first fall frost is October 7, giving you a growing season of approximately 142 days.

At an elevation of 1,026 feet, Jefferson County receives approximately 42.6 inches of rainfall annually with predominantly silt loam soil. Summer highs average 83ยฐF, so choose short-season varieties of Cauliflower to ensure they mature before fall.

Jefferson County, PA (Zone 5a) Short season
142 days
Last Spring Frost May 18
142 growing days
First Fall Frost October 7

Jefferson County Soil Profile

Soil Type

Silt Loam

Soil pH

4.8-6.4

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (26 days to spare)
Start indoors: Apr 4 Transplant: May 9 🍅 Harvest: Jul 4 – Sep 5
Recommended (50%) ✓ Fits season (23 days to spare)
Start indoors: Apr 13 Transplant: May 18 🍅 Harvest: Jul 13 – Sep 14
Safe Start (90%) ✓ Fits season (29 days to spare)
Start indoors: Apr 27 Transplant: Jun 1 🍅 Harvest: Jul 27 – Sep 28

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
1.3″/week
You supply
0.2″/week
Watering frequency Only during dry spells
Season total 303 gal / 100 sq ft
Cauliflower needs ~949 GDD — county provides 1,739 GDD Excellent fit

Cauliflower Planting Timeline โ€” Jefferson County, PA

Cauliflower Planting Calendar

Activity When Date Range
Start Indoors April 13 Apr 13 โ€“ Apr 27
Transplant Outdoors May 18 May 18 โ€“ Jun 1
Direct Sow May 4 May 4 โ€“ May 25
Fall Sowing July 29 Jul 29 โ€“ Aug 12
Harvest July 13 Jul 13 โ€“ Sep 14

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

Month-by-Month Timeline

MonthActivities
January โ€”
February โ€”
March โ€”
April Start Indoors
May Transplant Outdoors Direct Sow
June Transplant Outdoors
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 5a

Growing Season

142 days

Growing Tips for Jefferson 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 Jefferson County, PA?

Jefferson County is in Zone 5a with an average last frost of May 18. Plan your Cauliflower planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Jefferson County, PA?

Jefferson County, Pennsylvania is in USDA Hardiness Zone 5a. The average last spring frost is May 18 and first fall frost is October 7.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Jefferson County gardeners in Zone 5a 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 Jefferson County, PA. Local conditions may vary. Last updated: April 2026.