When to Plant Kale in Jefferson County, OK
Kale is an exceptionally hardy, nutrient-dense green available in curly, lacinato, and Russian varieties. It tolerates heavy frost and often tastes sweeter after cold exposure.
Jefferson County, Oklahoma is in USDA Zone 7b. The average last spring frost is March 26 and the first fall frost is November 9, giving you a growing season of approximately 228 days.
At an elevation of 883 feet, Jefferson County receives approximately 24.7 inches of rainfall annually with predominantly loam soil. Summer highs average 91°F, providing good warmth for Kale during the growing season.
Jefferson County Soil Profile
Soil Type
Loam
Soil pH
6.6-7.5
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 Jefferson County
How your county's soil matches Kale's growing requirements.
Soil pH
Your soil pH (6.6–7.5) is within Kale's preferred range (6.0–7.5).
Soil Texture
The loam soil in Jefferson County is excellent for Kale — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is excellent (4.1%) — Kale will thrive.
How to Plant Kale
Fall planting: Sow 10 weeks before your first frost date for a fall harvest.
Succession Planting Kale
Sow every 5.7 weeks. Last sowing by Aug 31 to harvest before frost.
For a dedicated fall crop, sow by Aug 31.
Plant Water Budget
Monthly Watering Guide for Kale
Kale needs approximately 0.8 inches of water per week (3.5" per month). Here's how your county's rainfall compares month by month.
| Month | Kale Needs | Rainfall | You Supplement | Action |
|---|---|---|---|---|
| Jan | — | 0.6" | 0" | ❄️ Dormant |
| Feb | — | 0.8" | 0" | ❄️ Dormant |
| Mar | 3.5" | 1.7" | 1.8" | 🚿 Regular watering |
| Apr | 3.5" | 2.7" | 0.8" | 💧 Light watering |
| May | 3.5" | 3.2" | 0.3" | 💧 Light watering |
| Jun | 3.5" | 4" | 0" | ✅ Rainfall sufficient |
| Jul | 3.5" | 3.1" | 0.4" | 💧 Light watering |
| Aug | 3.5" | 3.2" | 0.3" | 💧 Light watering |
| Sep | 3.5" | 2.1" | 1.4" | 💧 Light watering |
| Oct | 3.5" | 1.6" | 1.9" | 🚿 Regular watering |
| Nov | 3.5" | 0.8" | 2.7" | 🚿 Regular watering |
| Dec | — | 0.7" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Mar–Nov in Jefferson County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.
Kale 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.
Kale Planting Timeline — Jefferson County, OK
Kale Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | February 19 | Feb 19 – Mar 5 |
| Transplant Outdoors | March 26 | Mar 26 – Apr 9 |
| Direct Sow | March 12 | Mar 12 – Apr 2 |
| Harvest | May 21 | May 21 – Jul 16 |
| Fall Sowing | August 31 | Aug 31 – Sep 14 |
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 | Harvest |
| June | Harvest |
| July | Harvest |
| August | Fall Sowing |
| September | Fall Sowing |
| October | — |
| November | — |
| December | — |
Growing Conditions
☀️ Sun
Full Sun (6-8+ hours)
💧 Water
0.8"/week · 1-2 times/week
📅 Days to Maturity
50–70 days
🧪 Soil pH
Needs 6–7.5 · Your soil: ideal
🗺️ USDA Zone
Zone 7b
📆 Growing Season
228 days in Jefferson County
Growing Tips for Kale in Jefferson County
Direct sow Kale outdoors after March 26 in Jefferson County when soil has warmed and frost danger has passed.
Summer highs in Jefferson County reach 91°F — grow Kale as a spring or fall crop. Use shade cloth if planting in summer.
Common pests for Kale in this region include cabbage worm and flea beetles. Use row covers early in the season and inspect plants weekly.
General growing tips
Direct sow or transplant in early spring or late summer. Harvest outer leaves first to keep plants productive. Kale overwinters in many climates and can provide greens all year.
Companion Planting
Good Companions
Avoid Planting Near
Check more plant combinations with our Companion Planting Checker →
Isolate 1/2 mile from other brassicas (broccoli, cabbage, etc.) — they all cross.
Kale in Other Locations
Frequently Asked Questions
When should I plant Kale in Jefferson County, OK?
Jefferson County is in Zone 7b with an average last frost of March 26. Plan your Kale planting based on this frost date — see the calendar above for exact timing.
What planting zone is Jefferson County, OK?
Jefferson County, Oklahoma is in USDA Hardiness Zone 7b. The average last spring frost is March 26 and first fall frost is November 9.
Plan Your Garden with Confidence
Get our free Garden Planner — designed to help Jefferson County gardeners in Zone 7b 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.