When to plant Radish in Johnson County, KS
Johnson County gardeners should plant Radish between March 25 and April 15 in spring. With Johnson County's Zone 6b climate (last frost April 8), Radish needs 22–35 days to mature — plant by September 21 for a full harvest. A second sowing from August 17 to August 31 extends the harvest into fall.
When to Plant Radish in Johnson County, KS
June to-do list for Johnson County, Kansas
If you only do a handful of things in the garden this June, make it these. They're sequenced around your zone's frost timing.
Radishes are one of the fastest-growing vegetables, with some varieties ready in under a month. They come in round, elongated, and large winter types.
Johnson County, Kansas is in USDA Zone 6b. The average last spring frost is April 8 and the first fall frost is October 26, giving you a growing season of approximately 201 days.
At an elevation of 768 feet, Johnson County receives approximately 27.6 inches of rainfall annually with predominantly loam soil. Summer highs average 87°F, providing good warmth for Radish during the growing season.
Johnson County Soil Profile
Soil Type
Loam
Soil pH
6.8-7.2
Drainage
Well Drained
Radish 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 Radish's growing requirements.
Soil pH
Your soil pH (6.8–7.2) overlaps with Radish's range (6.0–7.0), though not a perfect match.
Soil Texture
The loam soil in Johnson County is excellent for Radish — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is excellent (4.2%) — Radish will thrive.
How to Plant Radish
Fall planting: Sow 10 weeks before your first frost date for a fall harvest.
Succession Planting Radish
Sow every 2.4 weeks. Last sowing by Sep 21 to harvest before frost.
For a dedicated fall crop, sow by Aug 17.
Radish Water Budget
Water stress score is 6/10 — consider drought-tolerant varieties and mulching
Monthly Watering Guide for Radish
Radish needs approximately 0.5 inches of water per week (2.2" per month). Here's how your county's rainfall compares month by month.
| Month | Radish Needs | Rainfall | You Supplement | Action |
|---|---|---|---|---|
| Jan | — | 0.8" | 0" | ❄️ Dormant |
| Feb | — | 0.8" | 0" | ❄️ Dormant |
| Mar | — | 1.9" | 0" | ❄️ Dormant |
| Apr | 2.2" | 3.2" | 0" | ✅ Rainfall sufficient |
| May | 2.2" | 3.7" | 0" | ✅ Rainfall sufficient |
| Jun | 2.2" | 4.1" | 0" | ✅ Rainfall sufficient |
| Jul | 2.2" | 3.8" | 0" | ✅ Rainfall sufficient |
| Aug | 2.2" | 3.5" | 0" | ✅ Rainfall sufficient |
| Sep | 2.2" | 2.3" | 0" | ✅ Rainfall sufficient |
| Oct | 2.2" | 1.8" | 0.4" | 💧 Light watering |
| Nov | — | 1" | 0" | ❄️ Dormant |
| Dec | — | 0.7" | 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.
Radish 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.
Radish Planting Timeline — Johnson County, KS
Radish Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Direct Sow | March 25 | Mar 25 – Apr 15 |
| Harvest | April 22 | Apr 22 – May 13 |
| Fall Sowing | August 17 | Aug 17 – Aug 31 |
Plant 0.5" deep · 2" apart · Rows 6" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | Direct Sow |
| April | Direct Sow Harvest |
| May | Harvest |
| June | — |
| July | — |
| August | Fall Sowing |
| September | — |
| October | — |
| November | — |
| December | — |
Growing Conditions
☀️ Sun
Full Sun (6-8+ hours)
💧 Water
0.5"/week · Natural rainfall sufficient
📅 Days to Maturity
22–35 days
🧪 Soil pH
Needs 6–7 · Your soil: acceptable
🗺️ USDA Zone
Zone 6b
📆 Growing Season
201 days in Johnson County
Growing Tips for Radish in Johnson County
Direct sow Radish outdoors after April 08 in Johnson County when soil has warmed and frost danger has passed.
Your generous 201.0-day season in Johnson County allows multiple plantings of Radish. Sow every 11.0 days for continuous harvest.
Common pests for Radish 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 every 1-2 weeks for continuous harvest. Do not transplant. Harvest spring radishes promptly to prevent them from becoming pithy and hot.
Companion Planting
Good Companions
Avoid Planting Near
Check more plant combinations with our Companion Planting Checker →
Radish in Other Locations
Frequently Asked Questions
When should I plant Radish in Johnson County, KS?
Johnson County is in Zone 6b with an average last frost of April 8. Plan your Radish planting based on this frost date — see the calendar above for exact timing.
What planting zone is Johnson County, KS?
Johnson County, Kansas is in USDA Hardiness Zone 6b. The average last spring frost is April 8 and first fall frost is October 26.
When should I plant Radish in Johnson County, KS?
In Johnson County, KS, plant Radish after the last frost (around April 8) and before the first frost (around October 26). Best results when soil holds above 50°F.
What growing zone is Johnson County, KS for Radish?
Johnson County sits in USDA Zone 6b. Radish grows reliably in zones 2a through 11b, so it's a good fit here.
Can Radish grow in Johnson County's climate?
Yes — Radish grows well in Johnson County's temperate climate. Johnson County averages a 201-day frost-free season, with last frost around April 8 and first frost around October 26.
Your Johnson County Garden Planner — Free
A 22-page printable planner built for Johnson 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.