When to Plant Acorn Squash in Putnam County, IL
This month in Putnam County, Illinois
Your garden in Putnam County, Illinois is working on a schedule, even when you're not. Here's where you should be this May.
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Harden off and plant acorn squash
Water the tray well an hour before you transplant. Roots slide out cleanly and settle in faster.
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Fire up the seed-starting tray: acorn squash
Label every cell. You will absolutely forget which is which otherwise.
Acorn squash is a small winter squash with dark green, ribbed skin and mildly sweet orange flesh. It is perfect for stuffing and roasting as individual servings.
Putnam County, Illinois is in USDA Zone 5b. The average last spring frost is April 21 and the first fall frost is October 13, giving you a growing season of approximately 175 days.
At an elevation of 582 feet, Putnam County receives approximately 41.5 inches of rainfall annually with predominantly silt loam soil. Summer highs average 87°F, providing good warmth for Acorn Squash during the growing season.
Putnam County Soil Profile
Soil Type
Silt Loam
Soil pH
6-6.7
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 Putnam County
How your county's soil matches Acorn Squash's growing requirements.
Soil pH
Your soil pH (6.0–6.7) is within Acorn Squash's preferred range (5.5–7.0).
Soil Texture
The silt loam soil in Putnam County is excellent for Acorn Squash — good drainage, moisture retention, and nutrient holding capacity.
Drainage
Drainage is adequate for Acorn Squash.
Organic Matter
Organic matter is excellent (4.3%) — Acorn Squash will thrive.
How to Plant Acorn Squash
Succession Planting Acorn Squash
Sow every 9.1 weeks. Last sowing by Jul 05 to harvest before frost.
Plant Water Budget
Monthly Watering Guide for Acorn Squash
Acorn Squash 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 | Acorn Squash Needs | Rainfall | You Supplement | Action |
|---|---|---|---|---|
| Jan | — | 1.8" | 0" | ❄️ Dormant |
| Feb | — | 2" | 0" | ❄️ Dormant |
| Mar | — | 3.1" | 0" | ❄️ Dormant |
| Apr | 4.8" | 3.6" | 1.2" | 💧 Light watering |
| May | 4.8" | 4.3" | 0.5" | 💧 Light watering |
| Jun | 4.8" | 5.2" | 0" | ✅ Rainfall sufficient |
| Jul | 4.8" | 5" | 0" | ✅ Rainfall sufficient |
| Aug | 4.8" | 4.3" | 0.5" | 💧 Light watering |
| Sep | 4.8" | 3.3" | 1.5" | 💧 Light watering |
| Oct | 4.8" | 3.3" | 1.5" | 💧 Light watering |
| Nov | — | 3.2" | 0" | ❄️ Dormant |
| Dec | — | 2.5" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Apr–Oct in Putnam County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.
Acorn Squash 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.
Acorn Squash Planting Timeline — Putnam County, IL
Acorn Squash Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | March 17 | Mar 17 – Mar 31 |
| Transplant Outdoors | May 5 | May 5 – May 19 |
| Direct Sow | April 28 | Apr 28 – May 19 |
| Harvest | July 28 | Jul 28 – Sep 1 |
Plant 1" deep · 30" apart · Rows 42" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | Start Indoors |
| April | Direct Sow |
| May | Transplant Outdoors Direct Sow |
| June | — |
| July | Harvest |
| August | Harvest |
| September | Harvest |
| October | — |
| November | — |
| December | — |
Growing Conditions
☀️ Sun
Full Sun (6-8+ hours)
💧 Water
1.1"/week · 1-2 times/week
📅 Days to Maturity
80–100 days
🧪 Soil pH
Needs 5.5–7 · Your soil: ideal
🗺️ USDA Zone
Zone 5b
📆 Growing Season
175 days in Putnam County
Growing Tips for Acorn Squash in Putnam County
Direct sow Acorn Squash outdoors after April 21 in Putnam County when soil has warmed and frost danger has passed.
Common pests for Acorn Squash in this region include squash vine borer and cucumber beetles. Use row covers early in the season and inspect plants weekly.
General growing tips
Direct sow after last frost. Harvest when the ground spot turns orange and the skin is hard. Acorn squash has a shorter storage life than butternut, lasting about 2 months.
Companion Planting
Good Companions
Avoid Planting Near
Check more plant combinations with our Companion Planting Checker →
Acorn Squash in Other Locations
Frequently Asked Questions
When should I plant Acorn Squash in Putnam County, IL?
Putnam County is in Zone 5b with an average last frost of April 21. Plan your Acorn Squash planting based on this frost date — see the calendar above for exact timing.
What planting zone is Putnam County, IL?
Putnam County, Illinois is in USDA Hardiness Zone 5b. The average last spring frost is April 21 and first fall frost is October 13.
Your Putnam County Garden Planner — Free
A 24-page printable planner built for Putnam 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.