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When to Plant Brussels Sprouts in Geary County, KS

Geary County, Kansas Zone 6b May

Your May game plan for Geary County, Kansas

Your Geary County, Kansas garden is entering a new phase. Here's what's on the schedule for May and why each task matters now.

Avg. last frost April 15
Avg. first frost October 20
Soil temp (4") 64°F
Watering Low
Pest pressure Low
Daylight 14.1 hrs
  1. Indoor seed-starting week for brussels sprouts

    These need a head start before your last frost (April 15). Sow into cells now so you're ready to transplant in a few weeks.

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

Geary County, Kansas is in USDA Zone 6b. The average last spring frost is April 15 and the first fall frost is October 20, giving you a growing season of approximately 188 days.

At an elevation of 610 feet, Geary County receives approximately 31.2 inches of rainfall annually with predominantly loam soil. Summer highs average 88°F, providing good warmth for Brussels Sprouts during the growing season.

Geary County, KS (Zone 6b) Moderate season
188 days
Last Spring Frost April 15
188 growing days
First Fall Frost October 20

Geary County Soil Profile

Soil Type

Loam

Soil pH

6.4-7.8

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (38 days to spare)
Start indoors: Mar 7 Transplant: Apr 11 🍅 Harvest: Jul 11 – Sep 5
Recommended (50%) ✓ Fits season (41 days to spare)
Start indoors: Mar 11 Transplant: Apr 15 🍅 Harvest: Jul 15 – Sep 9
Safe Start (90%) ✓ Fits season (40 days to spare)
Start indoors: Mar 26 Transplant: Apr 30 🍅 Harvest: Jul 30 – Sep 24

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 Geary County

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

Soil pH

Your soil pH (6.4–7.8) overlaps with Brussels Sprouts's range (6.0–7.5), though not a perfect match.

Soil Texture

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

Organic Matter

Organic matter is moderate (3.3%). 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
0.7″/week
You supply
0.2″/week
Watering frequency Only during dry spells
Season total 408 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 0.8" 0" ❄️ Dormant
Feb 1.1" 0" ❄️ Dormant
Mar 1.8" 0" ❄️ Dormant
Apr 3.9" 3.3" 0.6" 💧 Light watering
May 3.9" 4.9" 0" ✅ Rainfall sufficient
Jun 3.9" 4.5" 0" ✅ Rainfall sufficient
Jul 3.9" 3.8" 0.1" 💧 Light watering
Aug 3.9" 3.8" 0.1" 💧 Light watering
Sep 3.9" 3.2" 0.7" 💧 Light watering
Oct 3.9" 1.9" 2" 🚿 Regular watering
Nov 1.2" 0" ❄️ Dormant
Dec 0.7" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Geary 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 ~1,760 GDD — county provides 3,008 GDD Excellent fit

Brussels Sprouts Planting Timeline — Geary County, KS

Brussels Sprouts Planting Calendar

Activity When Date Range
Start Indoors March 11 Mar 11 – Mar 25
Transplant Outdoors April 15 Apr 15 – Apr 29
Direct Sow April 1 Apr 1 – Apr 22
Harvest July 15 Jul 15 – Sep 9
Fall Sowing August 11 Aug 11 – Aug 25

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

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.9"/week · Only during dry spells

📅 Days to Maturity

90–130 days

🧪 Soil pH

Needs 6–7.5 · Your soil: acceptable

🗺️ USDA Zone

Zone 6b

📆 Growing Season

188 days in Geary County

Growing Tips for Brussels Sprouts in Geary County

Direct sow Brussels Sprouts outdoors after April 15 in Geary 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 Geary County, KS?

Geary County is in Zone 6b with an average last frost of April 15. Plan your Brussels Sprouts planting based on this frost date — see the calendar above for exact timing.

What planting zone is Geary County, KS?

Geary County, Kansas is in USDA Hardiness Zone 6b. The average last spring frost is April 15 and first fall frost is October 20.

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Your Geary County Garden Planner — Free

A 24-page printable planner built for Geary County (Zone 6b). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.

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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 Geary County, KS. 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.