When to Plant Radicchio in Houghton County, MI
Your May planting checklist for Houghton County, Michigan
May rewards gardeners who work with the weather, not against it. Here's how to stay in step this month in Houghton County, Michigan.
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Harden off and plant radicchio
Pinch off the lowest leaves on each seedling before you plant — it reduces water loss while the roots catch up.
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Outdoor sowing time: radicchio
Keep the top inch of soil moist until germination — a gentle morning watering for 5–7 days does the job.
Looking ahead to June
- Starting indoors: radicchio
Radicchio is an Italian chicory with stunning red and white leaves and a pleasantly bitter flavor. It forms tight heads and is used in salads, grilled, or braised.
Houghton County, Michigan is in USDA Zone 5b. The average last spring frost is May 19 and the first fall frost is October 2, giving you a growing season of approximately 136 days.
At an elevation of 956 feet, Houghton County receives approximately 34.5 inches of rainfall annually with predominantly silt loam soil. Summer highs average 84°F, so choose short-season varieties of Radicchio to ensure they mature before fall.
Houghton County Soil Profile
Soil Type
Silt Loam
Soil pH
5.9-7.2
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 Houghton County
How your county's soil matches Radicchio's growing requirements.
Soil pH
Your soil pH (5.9–7.2) overlaps with Radicchio's range (6.0–7.0), though not a perfect match.
Soil Texture
The silt loam soil in Houghton County is excellent for Radicchio — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is moderate (3.9%). Annual compost additions will help Radicchio.
How to Plant Radicchio
Fall planting: Sow 10 weeks before your first frost date for a fall harvest.
Succession Planting Radicchio
Sow every 6.9 weeks. Last sowing by Jul 14 to harvest before frost.
For a dedicated fall crop, sow by Jul 24.
Plant Water Budget
Monthly Watering Guide for Radicchio
Radicchio needs approximately 0.7 inches of water per week (3" per month). Here's how your county's rainfall compares month by month.
| Month | Radicchio Needs | Rainfall | You Supplement | Action |
|---|---|---|---|---|
| Jan | — | 1.3" | 0" | ❄️ Dormant |
| Feb | — | 1.7" | 0" | ❄️ Dormant |
| Mar | — | 2.6" | 0" | ❄️ Dormant |
| Apr | — | 3.6" | 0" | ❄️ Dormant |
| May | 3" | 3.8" | 0" | ✅ Rainfall sufficient |
| Jun | 3" | 4.2" | 0" | ✅ Rainfall sufficient |
| Jul | 3" | 3.3" | 0" | ✅ Rainfall sufficient |
| Aug | 3" | 3.5" | 0" | ✅ Rainfall sufficient |
| Sep | 3" | 3.4" | 0" | ✅ Rainfall sufficient |
| Oct | 3" | 2.9" | 0.1" | 💧 Light watering |
| Nov | — | 2.1" | 0" | ❄️ Dormant |
| Dec | — | 2" | 0" | ❄️ Dormant |
Water needs are for active growing months only (May–Oct in Houghton County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.
Radicchio 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.
Radicchio Planting Timeline — Houghton County, MI
Radicchio Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | April 14 | Apr 14 – Apr 28 |
| Transplant Outdoors | May 19 | May 19 – Jun 2 |
| Direct Sow | May 5 | May 5 – May 26 |
| Harvest | July 21 | Jul 21 – Aug 25 |
| Fall Sowing | July 24 | Jul 24 – Aug 7 |
Plant 0.5" deep · 6" apart · Rows 12" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | — |
| April | Start Indoors |
| May | Transplant Outdoors Direct Sow |
| June | Transplant Outdoors |
| July | Fall Sowing Harvest |
| August | Fall Sowing Harvest |
| September | — |
| October | — |
| November | — |
| December | — |
Growing Conditions
☀️ Sun
Full Sun (6-8+ hours)
💧 Water
0.7"/week · Natural rainfall sufficient
📅 Days to Maturity
60–80 days
🧪 Soil pH
Needs 6–7 · Your soil: acceptable
🗺️ USDA Zone
Zone 5b
📆 Growing Season
136 days in Houghton County
Growing Tips for Radicchio in Houghton County
Direct sow Radicchio outdoors after May 19 in Houghton County when soil has warmed and frost danger has passed.
Common pests for Radicchio in this region include aphids and slugs. Use row covers early in the season and inspect plants weekly.
General growing tips
Start in late summer for fall harvest. The red color develops with cool nights and light frost. Harvest when heads are firm and compact.
Companion Planting
Good Companions
Avoid Planting Near
Check more plant combinations with our Companion Planting Checker →
Radicchio in Other Locations
Frequently Asked Questions
When should I plant Radicchio in Houghton County, MI?
Houghton County is in Zone 5b with an average last frost of May 19. Plan your Radicchio planting based on this frost date — see the calendar above for exact timing.
What planting zone is Houghton County, MI?
Houghton County, Michigan is in USDA Hardiness Zone 5b. The average last spring frost is May 19 and first fall frost is October 2.
Your Houghton County Garden Planner — Free
A 24-page printable planner built for Houghton County (Zone 5b). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.