When to Plant Daikon in St. Clair County, IL
Daikon is a large, mild Japanese radish that can grow over a foot long. It is excellent for pickling, stir-fries, and as a soil-breaking cover crop.
St. Clair County, Illinois is in USDA Zone 6b. The average last spring frost is April 2 and the first fall frost is November 2, giving you a growing season of approximately 214 days.
At an elevation of 711 feet, St. Clair County receives approximately 34.1 inches of rainfall annually with predominantly silt loam soil. Summer highs average 89°F, providing good warmth for Daikon during the growing season.
St. Clair County Soil Profile
Soil Type
Silt Loam
Soil pH
6-7.3
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 St. Clair County
How your county's soil matches Daikon's growing requirements.
Soil pH
Your soil pH (6.0–7.3) overlaps with Daikon's range (5.8–7.0), though not a perfect match.
Soil Texture
The silt loam soil in St. Clair County is excellent for Daikon — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is excellent (5.1%) — Daikon will thrive.
How to Plant Daikon
Fall planting: Sow 10 weeks before your first frost date for a fall harvest.
Succession Planting Daikon
Sow every 5.7 weeks. Last sowing by Aug 24 to harvest before frost.
For a dedicated fall crop, sow by Aug 24.
Plant Water Budget
Water stress score is 6/10 — consider drought-tolerant varieties and mulching
Monthly Watering Guide for Daikon
Daikon needs approximately 1 inches of water per week (4.3" per month). Here's how your county's rainfall compares month by month.
| Month | Daikon Needs | Rainfall | You Supplement | Action |
|---|---|---|---|---|
| Jan | — | 1.5" | 0" | ❄️ Dormant |
| Feb | — | 1.5" | 0" | ❄️ Dormant |
| Mar | — | 2.5" | 0" | ❄️ Dormant |
| Apr | 4.3" | 3.2" | 1.1" | 💧 Light watering |
| May | 4.3" | 3.8" | 0.5" | 💧 Light watering |
| Jun | 4.3" | 4" | 0.3" | 💧 Light watering |
| Jul | 4.3" | 3.8" | 0.5" | 💧 Light watering |
| Aug | 4.3" | 3.9" | 0.4" | 💧 Light watering |
| Sep | 4.3" | 3.3" | 1" | 💧 Light watering |
| Oct | 4.3" | 2.5" | 1.8" | 💧 Light watering |
| Nov | 4.3" | 2.4" | 1.9" | 💧 Light watering |
| Dec | — | 1.8" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Apr–Nov in St. Clair County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.
Daikon 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.
Daikon Planting Timeline — St. Clair County, IL
Daikon Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Direct Sow | March 19 | Mar 19 – Apr 9 |
| Harvest | May 14 | May 14 – Jun 11 |
| Fall Sowing | August 24 | Aug 24 – Sep 7 |
Plant 0.5" deep · 6" apart · Rows 12" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | Direct Sow |
| April | Direct Sow |
| May | Harvest |
| June | Harvest |
| July | — |
| August | Fall Sowing |
| September | Fall Sowing |
| October | — |
| November | — |
| December | — |
Growing Conditions
☀️ Sun
Full Sun (6-8+ hours)
💧 Water
1"/week · 1-2 times/week
📅 Days to Maturity
50–70 days
🧪 Soil pH
Needs 5.8–7 · Your soil: acceptable
🗺️ USDA Zone
Zone 6b
📆 Growing Season
214 days in St. Clair County
Growing Tips for Daikon in St. Clair County
Direct sow Daikon outdoors after April 02 in St. Clair County when soil has warmed and frost danger has passed.
Common pests for Daikon 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 in late summer for fall harvest. Loosen soil deeply before planting. Thin seedlings to 6 inches apart. Harvest before hard freeze as exposed shoulders may crack.
Companion Planting
Good Companions
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Check more plant combinations with our Companion Planting Checker →
Daikon in Other Locations
Frequently Asked Questions
When should I plant Daikon in St. Clair County, IL?
St. Clair County is in Zone 6b with an average last frost of April 2. Plan your Daikon planting based on this frost date — see the calendar above for exact timing.
What planting zone is St. Clair County, IL?
St. Clair County, Illinois is in USDA Hardiness Zone 6b. The average last spring frost is April 2 and first fall frost is November 2.
Plan Your Garden with Confidence
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