When to Plant Brussels Sprouts in Harmon County, OK
Brussels sprouts are a cold-hardy brassica that produces miniature cabbage-like heads along a tall stalk. Flavor improves after a light frost.
Harmon County, Oklahoma is in USDA Zone 7b. The average last spring frost is March 31 and the first fall frost is November 5, giving you a growing season of approximately 219 days.
At an elevation of 993 feet, Harmon County receives approximately 34.4 inches of rainfall annually with predominantly loam soil. Summer highs average 91°F, providing good warmth for Brussels Sprouts during the growing season.
Harmon County Soil Profile
Soil Type
Loam
Soil pH
6.5-7.5
Drainage
Well Drained
Plant Planting Risk Windows
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 Harmon County
How your county's soil matches Brussels Sprouts's growing requirements.
Soil pH
Your soil pH (6.5–7.5) is within Brussels Sprouts's preferred range (6.0–7.5).
Soil Texture
The loam soil in Harmon County is excellent for Brussels Sprouts — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is excellent (4.0%) — Brussels Sprouts will thrive.
How to Plant Brussels Sprouts
Fall planting: Sow 10 weeks before your first frost date for a fall harvest.
Plant Water Budget
Water stress score is 8/10 — 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 | — | 0.9" | 0" | ❄️ Dormant |
| Feb | — | 1.2" | 0" | ❄️ Dormant |
| Mar | 3.9" | 2.3" | 1.6" | 💧 Light watering |
| Apr | 3.9" | 3.7" | 0.2" | 💧 Light watering |
| May | 3.9" | 5.1" | 0" | ✅ Rainfall sufficient |
| Jun | 3.9" | 5" | 0" | ✅ Rainfall sufficient |
| Jul | 3.9" | 4.1" | 0" | ✅ Rainfall sufficient |
| Aug | 3.9" | 4.8" | 0" | ✅ Rainfall sufficient |
| Sep | 3.9" | 3" | 0.9" | 💧 Light watering |
| Oct | 3.9" | 2" | 1.9" | 💧 Light watering |
| Nov | 3.9" | 1.3" | 2.6" | 🚿 Regular watering |
| Dec | — | 1" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Mar–Nov in Harmon 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 Planting Timeline — Harmon County, OK
Brussels Sprouts Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | February 24 | Feb 24 – Mar 10 |
| Transplant Outdoors | March 31 | Mar 31 – Apr 14 |
| Direct Sow | March 17 | Mar 17 – Apr 7 |
| Harvest | June 30 | Jun 30 – Aug 25 |
| Fall Sowing | August 27 | Aug 27 – Sep 10 |
Plant 1" deep · 15" apart · Rows 24" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | Start Indoors |
| March | Start Indoors Transplant Outdoors Direct Sow |
| April | Transplant Outdoors Direct Sow |
| May | — |
| June | Harvest |
| July | Harvest |
| August | Fall Sowing Harvest |
| September | Fall Sowing |
| 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: ideal
🗺️ USDA Zone
Zone 7b
📆 Growing Season
219 days in Harmon County
Growing Tips for Brussels Sprouts in Harmon County
Direct sow Brussels Sprouts outdoors after March 31 in Harmon County when soil has warmed and frost danger has passed.
Summer highs in Harmon County reach 91°F — grow Brussels Sprouts as a spring or fall crop. Use shade cloth if planting in summer.
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
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Brussels Sprouts in Other Locations
Frequently Asked Questions
When should I plant Brussels Sprouts in Harmon County, OK?
Harmon County is in Zone 7b with an average last frost of March 31. Plan your Brussels Sprouts planting based on this frost date — see the calendar above for exact timing.
What planting zone is Harmon County, OK?
Harmon County, Oklahoma is in USDA Hardiness Zone 7b. The average last spring frost is March 31 and first fall frost is November 5.
Plan Your Garden with Confidence
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