When to Plant Tomatillo in Marathon County, WI
Tomatillos are a Mexican staple that produces tart, green fruits enclosed in papery husks. They are essential for salsa verde and green sauces.
Marathon County, Wisconsin is in USDA Zone 4a. The average last spring frost is May 11 and the first fall frost is October 2, giving you a growing season of approximately 144 days.
At an elevation of 723 feet, Marathon County receives approximately 39.9 inches of rainfall annually with predominantly silt loam soil. Summer highs average 83°F, so choose short-season varieties of Tomatillo to ensure they mature before fall.
Marathon 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 Marathon County
How your county's soil matches Tomatillo's growing requirements.
Soil pH
Your soil pH (6.0–7.3) overlaps with Tomatillo's range (6.0–7.0), though not a perfect match.
Soil Texture
The silt loam soil in Marathon County is excellent for Tomatillo — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is excellent (4.1%) — Tomatillo will thrive.
How to Plant Tomatillo
Succession Planting Tomatillo
Sow every 6.9 weeks. Last sowing by Jul 09 to harvest before frost.
Plant Water Budget
Monthly Watering Guide for Tomatillo
Tomatillo needs approximately 1.1 inches of water per week (4.8" per month). Here's how your county's rainfall compares month by month.
| Month | Tomatillo Needs | Rainfall | You Supplement | Action |
|---|---|---|---|---|
| Jan | — | 1.7" | 0" | ❄️ Dormant |
| Feb | — | 2" | 0" | ❄️ Dormant |
| Mar | — | 2.7" | 0" | ❄️ Dormant |
| Apr | — | 4.3" | 0" | ❄️ Dormant |
| May | 4.8" | 5" | 0" | ✅ Rainfall sufficient |
| Jun | 4.8" | 4.5" | 0.3" | 💧 Light watering |
| Jul | 4.8" | 4.8" | 0" | ✅ Rainfall sufficient |
| Aug | 4.8" | 4.6" | 0.2" | 💧 Light watering |
| Sep | 4.8" | 3.1" | 1.7" | 💧 Light watering |
| Oct | 4.8" | 3" | 1.8" | 💧 Light watering |
| Nov | — | 2.4" | 0" | ❄️ Dormant |
| Dec | — | 1.9" | 0" | ❄️ Dormant |
Water needs are for active growing months only (May–Oct in Marathon County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.
Tomatillo 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.
Tomatillo Planting Timeline — Marathon County, WI
Tomatillo Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | March 9 | Mar 9 – Mar 23 |
| Transplant Outdoors | June 1 | Jun 1 – Jun 15 |
| Direct Sow | May 25 | May 25 – Jun 15 |
| Harvest | August 3 | Aug 3 – Oct 12 |
Plant 1" deep · 15" apart · Rows 24" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | Start Indoors |
| April | — |
| May | Direct Sow |
| June | Transplant Outdoors Direct Sow |
| July | — |
| August | Harvest |
| September | Harvest |
| October | Harvest |
| November | — |
| December | — |
Growing Conditions
☀️ Sun
Full Sun (6-8+ hours)
💧 Water
1.1"/week · Natural rainfall sufficient
📅 Days to Maturity
60–85 days
🧪 Soil pH
Needs 6–7 · Your soil: acceptable
🗺️ USDA Zone
Zone 4a
📆 Growing Season
144 days in Marathon County
Growing Tips for Tomatillo in Marathon County
Direct sow Tomatillo outdoors after May 11 in Marathon County when soil has warmed and frost danger has passed.
Common pests for Tomatillo in this region include tomato hornworm and aphids. Use row covers early in the season and inspect plants weekly.
General growing tips
Start seeds indoors 6-8 weeks before last frost. Plant at least two plants for cross-pollination. Harvest when fruits fill the husk and it begins to split.
Companion Planting
Good Companions
Avoid Planting Near
Check more plant combinations with our Companion Planting Checker →
Tomatillo in Other Locations
Frequently Asked Questions
When should I plant Tomatillo in Marathon County, WI?
Marathon County is in Zone 4a with an average last frost of May 11. Plan your Tomatillo planting based on this frost date — see the calendar above for exact timing.
What planting zone is Marathon County, WI?
Marathon County, Wisconsin is in USDA Hardiness Zone 4a. The average last spring frost is May 11 and first fall frost is October 2.
Plan Your Garden with Confidence
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