When to Plant Corn in Johnson County, KY
Corn is a warm-season grass grown for its sweet ears, which are best eaten soon after harvest. It is wind-pollinated and must be planted in blocks for good kernel fill.
Johnson County, Kentucky is in USDA Zone 6b. The average last spring frost is April 14 and the first fall frost is October 26, giving you a growing season of approximately 195 days.
At an elevation of 3,308 feet, Johnson County receives approximately 47 inches of rainfall annually with predominantly silt loam soil. Summer highs average 86°F, providing good warmth for Corn during the growing season.
Johnson County Soil Profile
Soil Type
Silt Loam
Soil pH
5.3-7
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 Johnson County
How your county's soil matches Corn's growing requirements.
Soil pH
Your soil pH (5.3–7.0) overlaps with Corn's range (6.0–7.0), though not a perfect match.
Soil Texture
The silt loam soil in Johnson County is excellent for Corn — good drainage, moisture retention, and nutrient holding capacity.
Drainage
Drainage is adequate for Corn.
Organic Matter
Organic matter is moderate (3.0%). Annual compost additions will help Corn.
How to Plant Corn
Succession Planting Corn
Sow every 6.9 weeks. Last sowing by Jul 18 to harvest before frost.
Plant Water Budget
Water stress score is 6/10 — consider drought-tolerant varieties and mulching
Monthly Watering Guide for Corn
Corn needs approximately 1.5 inches of water per week (6.5" per month). Here's how your county's rainfall compares month by month.
| Month | Corn Needs | Rainfall | You Supplement | Action |
|---|---|---|---|---|
| Jan | — | 3.4" | 0" | ❄️ Dormant |
| Feb | — | 4.2" | 0" | ❄️ Dormant |
| Mar | — | 5.1" | 0" | ❄️ Dormant |
| Apr | 6.5" | 4.1" | 2.4" | 💧 Light watering |
| May | 6.5" | 3.5" | 3" | 💧 Light watering |
| Jun | 6.5" | 4.6" | 1.9" | 💧 Light watering |
| Jul | 6.5" | 4.6" | 1.9" | 💧 Light watering |
| Aug | 6.5" | 4.4" | 2.1" | 💧 Light watering |
| Sep | 6.5" | 3.5" | 3" | 💧 Light watering |
| Oct | 6.5" | 2.6" | 3.9" | 🚿 Regular watering |
| Nov | — | 3.6" | 0" | ❄️ Dormant |
| Dec | — | 3.5" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Apr–Oct in Johnson County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.
Corn 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.
Corn Planting Timeline — Johnson County, KY
Corn Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Direct Sow | April 21 | Apr 21 – May 12 |
| Harvest | June 23 | Jun 23 – Aug 18 |
Plant 1" deep · 12" apart · Rows 36" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | — |
| April | Direct Sow |
| May | Direct Sow |
| June | Harvest |
| July | Harvest |
| August | Harvest |
| September | — |
| October | — |
| November | — |
| December | — |
Growing Conditions
☀️ Sun
Full Sun (6-8+ hours)
💧 Water
1.5"/week · Only during dry spells
📅 Days to Maturity
60–100 days
🧪 Soil pH
Needs 6–7 · Your soil: acceptable
🗺️ USDA Zone
Zone 6b
📆 Growing Season
195 days in Johnson County
Growing Tips for Corn in Johnson County
Direct sow Corn outdoors after April 14 in Johnson County when soil has warmed and frost danger has passed.
Common pests for Corn in this region include corn earworm and corn borers. Use row covers early in the season and inspect plants weekly.
General growing tips
Plant in blocks of at least 4 rows rather than single rows for proper pollination. Direct sow after soil reaches 60F. Side-dress with nitrogen when plants are knee-high.
Companion Planting
Good Companions
Avoid Planting Near
Check more plant combinations with our Companion Planting Checker →
Corn in Other Locations
Frequently Asked Questions
When should I plant Corn in Johnson County, KY?
Johnson County is in Zone 6b with an average last frost of April 14. Plan your Corn planting based on this frost date — see the calendar above for exact timing.
What planting zone is Johnson County, KY?
Johnson County, Kentucky is in USDA Hardiness Zone 6b. The average last spring frost is April 14 and first fall frost is October 26.
Plan Your Garden with Confidence
Get our free Garden Planner — designed to help Johnson County gardeners in Zone 6b organize planting dates, track what's growing, and never miss a planting window.
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