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When to Plant Brussels Sprouts in Jackson County, OR

Brussels sprouts are a cold-hardy brassica that produces miniature cabbage-like heads along a tall stalk. Flavor improves after a light frost.

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 Brussels Sprouts 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 (12 days to spare)
Start indoors: Mar 22 Transplant: Apr 26 🍅 Harvest: Jul 26 – Sep 20
Recommended (50%) ✓ Fits season (9 days to spare)
Start indoors: Apr 2 Transplant: May 7 🍅 Harvest: Aug 6 – Oct 1
Safe Start (90%) ✓ Fits season (13 days to spare)
Start indoors: Apr 28 Transplant: Jun 2 🍅 Harvest: Sep 1 – Oct 27

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.

Soil Compatibility in Jackson County

How your county's soil matches Brussels Sprouts's growing requirements.

Soil pH

Your soil pH (5.3โ€“6.4) is more acidic than Brussels Sprouts prefers (6.0โ€“7.5). Add garden lime to raise pH.

Soil Texture

The silt loam soil in Jackson County is excellent for Brussels Sprouts โ€” good drainage, moisture retention, and nutrient holding capacity.

Drainage

Drainage is adequate for Brussels Sprouts.

Organic Matter

Organic matter is excellent (5.0%) โ€” Brussels Sprouts will thrive.

How to Plant Brussels Sprouts

1"
Planting Depth
15"
Between Plants
24"
Between Rows

Fall planting: Sow 10 weeks before your first frost date for a fall harvest.

Plant Water Budget

Plant needs
0.9″/week
Rainfall provides
1.2″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft

Monthly Watering Guide for Brussels Sprouts

Brussels Sprouts needs approximately 0.9 inches of water per week (3.9" per month). Here's how your county's rainfall compares month by month.

Month Brussels Sprouts Needs Rainfall You Supplement Action
Jan โ€” 6.1" 0" โ„๏ธ Dormant
Feb โ€” 5.8" 0" โ„๏ธ Dormant
Mar โ€” 5.1" 0" โ„๏ธ Dormant
Apr โ€” 3" 0" โ„๏ธ Dormant
May 3.9" 2.8" 1.1" ๐Ÿ’ง Light watering
Jun 3.9" 1.7" 2.2" ๐Ÿšฟ Regular watering
Jul 3.9" 0.7" 3.2" ๐Ÿšฟ Regular watering
Aug 3.9" 1" 2.9" ๐Ÿšฟ Regular watering
Sep 3.9" 1.8" 2.1" ๐Ÿšฟ Regular watering
Oct 3.9" 3.5" 0.4" ๐Ÿ’ง Light watering
Nov โ€” 6.4" 0" โ„๏ธ Dormant
Dec โ€” 8.2" 0" โ„๏ธ Dormant

Water needs are for active growing months only (Mayโ€“Oct in Jackson County). Supplement amounts are based on average rainfall โ€” actual needs vary with temperature, soil, and mulching.

Brussels Sprouts Heat Requirements (GDD)

What are Growing Degree Days (GDD)?

Growing Degree Days measure the total warmth your plants receive during the growing season. Think of it as a "heat bank" โ€” every day above 50ยฐF deposits warmth that helps your plants grow.

Each plant needs a certain amount of accumulated heat to mature. If your county provides more GDD than the plant needs, it's a great fit. If it's close, you may want to choose faster-maturing varieties or start seeds indoors to get a head start.

Brussels Sprouts needs ~1,760 GDD — county provides 2,496 GDD Excellent fit

Brussels Sprouts Planting Timeline โ€” Jackson County, OR

Brussels Sprouts 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
Harvest August 6 Aug 6 โ€“ Oct 1
Fall Sowing August 1 Aug 1 โ€“ Aug 15

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 โ€”
August Fall Sowing Harvest
September Harvest
October Harvest
November โ€”
December โ€”

Growing Conditions

โ˜€๏ธ Sun

Full Sun (6-8+ hours)

๐Ÿ’ง Water

0.9"/week ยท Natural rainfall sufficient

๐Ÿ“… Days to Maturity

90โ€“130 days

๐Ÿงช Soil pH

Needs 6โ€“7.5 ยท Your soil: too_acidic

๐Ÿ—บ๏ธ USDA Zone

Zone 8a

๐Ÿ“† Growing Season

156 days in Jackson County

Growing Tips for Brussels Sprouts in Jackson County

Direct sow Brussels Sprouts outdoors after May 07 in Jackson County when soil has warmed and frost danger has passed.

Common pests for Brussels Sprouts in this region include cabbage worm and flea beetles. Use row covers early in the season and inspect plants weekly.

General growing tips

Start seeds indoors 12-14 weeks before first fall frost. Stake tall plants to prevent toppling. Remove lower leaves as sprouts develop to improve air circulation.

Companion Planting

Good Companions

Avoid Planting Near

  • Tomatoes
  • Strawberries

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Brussels Sprouts in Jackson County, OR?

Jackson County is in Zone 8a with an average last frost of May 7. Plan your Brussels Sprouts 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.

Get Your Free Garden Planner →

Free download. Plan your entire garden season in minutes.

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.