Blog

When to plant Brussels Sprouts in Oneida County, ID

Oneida County gardeners should plant Brussels Sprouts between May 9 and May 30 in spring. With Oneida County's Zone 6a climate (last frost May 23), Brussels Sprouts needs 90–130 days to mature — plant by May 13 for a full harvest. A second sowing from July 12 to July 26 extends the harvest into fall.

When to Plant Brussels Sprouts in Oneida County, ID

Brussels Sprouts

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

Oneida County, Idaho is in USDA Zone 6a. The average last spring frost is May 23 and the first fall frost is September 20, giving you a growing season of approximately 120 days.

At an elevation of 8,042 feet, Oneida County receives approximately 18.4 inches of rainfall annually with predominantly loam soil. Summer highs average 85°F, providing good warmth for Brussels Sprouts during the growing season. With low rainfall, drip irrigation is essential for growing Brussels Sprouts successfully. Mulch heavily to conserve soil moisture.

Oneida County, ID (Zone 6a) Short season
120 days
Last Spring Frost May 23
120 growing days
First Fall Frost September 20

Oneida County Soil Profile

Soil Type

Loam

Soil pH

6.3-8.2

Drainage

Well Drained

Monthly Watering Guide for Brussels Sprouts

Brussels Sprouts needs approximately 1 inches of water per week (4.3" per month). Here's how your county's rainfall compares month by month.

Month Brussels Sprouts Needs Rainfall You Supplement Action
Jan 1.2" 0" ❄️ Dormant
Feb 1" 0" ❄️ Dormant
Mar 1.8" 0" ❄️ Dormant
Apr 1.8" 0" ❄️ Dormant
May 4.3" 2.1" 2.2" 🚿 Regular watering
Jun 4.3" 1.1" 3.2" 🚿 Regular watering
Jul 4.3" 1.8" 2.5" 🚿 Regular watering
Aug 4.3" 2" 2.3" 🚿 Regular watering
Sep 4.3" 1.7" 2.6" 🚿 Regular watering
Oct 1.7" 0" ❄️ Dormant
Nov 1.3" 0" ❄️ Dormant
Dec 0.9" 0" ❄️ Dormant

Water needs are for active growing months only (May–Sep in Oneida County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.

Brussels Sprouts Planting Timeline — Oneida County, ID

Brussels Sprouts Planting Calendar

Activity When Date Range
Start Indoors April 18 Apr 18 – May 2
Transplant Outdoors May 23 May 23 – Jun 6
Direct Sow May 9 May 9 – May 30
Harvest August 22 Aug 22 – Oct 17
Fall Sowing July 12 Jul 12 – Jul 26

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

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

Moderate — regular watering

📅 Days to Maturity

90–130 days

🧪 Soil pH

Needs 6–7.5 · Your soil: N/A

🗺️ USDA Zone

Zone 6a

📆 Growing Season

120 days in Oneida County

Growing Tips for Oneida County

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 Oneida County, ID?

Oneida County is in Zone 6a with an average last frost of May 23. Plan your Brussels Sprouts planting based on this frost date — see the calendar above for exact timing.

What planting zone is Oneida County, ID?

Oneida County, Idaho is in USDA Hardiness Zone 6a. The average last spring frost is May 23 and first fall frost is September 20.

When should I plant Brussels Sprouts in Oneida County, ID?

In Oneida County, ID, plant Brussels Sprouts after the last frost (around May 23) and before the first frost (around September 20). Best results when soil holds above 50°F.

What growing zone is Oneida County, ID for Brussels Sprouts?

Oneida County sits in USDA Zone 6a. Brussels Sprouts grows reliably in zones 2a through 10b, so it's a good fit here.

Can Brussels Sprouts grow in Oneida County's climate?

Yes — Brussels Sprouts grows well in Oneida County's temperate climate. Oneida County averages a 120-day frost-free season, with last frost around May 23 and first frost around September 20.

🌱

Your Oneida County Garden Planner — Free

A 22-page printable planner built for Oneida County (Zone 6a). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.

Instant PDF download. No spam, unsubscribe any time.

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

Sources & credits

Every number on this page traces back to a primary horticulture or government data source. Click through to verify.