Blog

When to Plant Brussels Sprouts in Minidoka County, ID

Minidoka County, Idaho Zone 6a May

What to do in May

May rewards gardeners who work with the weather, not against it. Here's how to stay in step this month in Minidoka County, Idaho.

Avg. last frost May 10
Avg. first frost October 3
Soil temp (4") 40°F
Watering High
Pest pressure Low
Daylight 14.4 hrs
  1. Move brussels sprouts from tray to bed

    Frost risk is low now in Minidoka County, Idaho. If you've been covering beds overnight, you can stop.

Coming up in June — start thinking about
  • Starting indoors: brussels sprouts

Instant PDF download. No spam, unsubscribe any time.

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

Minidoka County, Idaho is in USDA Zone 6a. The average last spring frost is May 10 and the first fall frost is October 3, giving you a growing season of approximately 146 days.

At an elevation of 5,990 feet, Minidoka County receives approximately 22.3 inches of rainfall annually with predominantly loam soil. Summer highs average 86°F, providing good warmth for Brussels Sprouts during the growing season.

Minidoka County, ID (Zone 6a) Short season
146 days
Last Spring Frost May 10
146 growing days
First Fall Frost October 3
Share this guide:

Minidoka County Soil Profile

Soil Type

Loam

Soil pH

6.6-7.8

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (1 days to spare)
Start indoors: Mar 27 Transplant: May 1 🍅 Harvest: Jul 31 – Sep 25
Recommended (50%) ✗ May not fit
Start indoors: Apr 5 Transplant: May 10 🍅 Harvest: Aug 9 – Oct 4
Safe Start (90%) ✗ May not fit
Start indoors: May 2 Transplant: Jun 6 🍅 Harvest: Sep 5 – Oct 31

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 Minidoka County

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

Soil pH

Your soil pH (6.6–7.8) overlaps with Brussels Sprouts's range (6.0–7.5), though not a perfect match.

Soil Texture

The loam soil in Minidoka County is excellent for Brussels Sprouts — good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is moderate (2.6%). Annual compost additions will help Brussels Sprouts.

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
0.6″/week
You supply
0.3″/week
Watering frequency 1-2 times/week
Season total 403 gal / 100 sq ft
Drought risk

Water stress score is 6/10 — consider drought-tolerant varieties and mulching

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 1.7" 0" ❄️ Dormant
Feb 1.2" 0" ❄️ Dormant
Mar 2" 0" ❄️ Dormant
Apr 2.5" 0" ❄️ Dormant
May 3.9" 2.5" 1.4" 💧 Light watering
Jun 3.9" 1.4" 2.5" 🚿 Regular watering
Jul 3.9" 2" 1.9" 💧 Light watering
Aug 3.9" 2.5" 1.4" 💧 Light watering
Sep 3.9" 2.1" 1.8" 💧 Light watering
Oct 3.9" 1.7" 2.2" 🚿 Regular watering
Nov 1.5" 0" ❄️ Dormant
Dec 1.2" 0" ❄️ Dormant

Water needs are for active growing months only (May–Oct in Minidoka County). Supplement amounts are based on average rainfall — 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" — every day above 50°F 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 ~1,595 GDD — county provides 2,117 GDD Excellent fit

Brussels Sprouts Planting Timeline — Minidoka County, ID

Brussels Sprouts Planting Calendar

Activity When Date Range
Start Indoors April 5 Apr 5 – Apr 19
Transplant Outdoors May 10 May 10 – May 24
Direct Sow April 26 Apr 26 – May 17
Harvest August 9 Aug 9 – Oct 4
Fall Sowing July 25 Jul 25 – Aug 8

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

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.9"/week · 1-2 times/week

📅 Days to Maturity

90–130 days

🧪 Soil pH

Needs 6–7.5 · Your soil: acceptable

🗺️ USDA Zone

Zone 6a

📆 Growing Season

146 days in Minidoka County

Growing Tips for Brussels Sprouts in Minidoka County

Direct sow Brussels Sprouts outdoors after May 10 in Minidoka 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.

Minidoka County receives only 22" of rain annually. Brussels Sprouts needs consistent moisture — install drip irrigation or water deeply 2-3 times per week.

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 Minidoka County, ID?

Minidoka County is in Zone 6a with an average last frost of May 10. Plan your Brussels Sprouts planting based on this frost date — see the calendar above for exact timing.

What planting zone is Minidoka County, ID?

Minidoka County, Idaho is in USDA Hardiness Zone 6a. The average last spring frost is May 10 and first fall frost is October 3.

🌱

Your Minidoka County Garden Planner — Free

A 24-page printable planner built for Minidoka 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 Minidoka County, ID. Local conditions may vary. Last updated: May 2026.

Sources & credits

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