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When to Plant Squash (Summer) in Mille Lacs County, MN

Mille Lacs County, Minnesota Zone 4a May

Your May game plan for Mille Lacs County, Minnesota

May is a pivotal month for Mille Lacs County, Minnesota gardens. Focus on these tasks first and you'll set up the rest of the season for success.

Avg. last frost May 1
Avg. first frost October 6
Soil temp (4") 53°F
Watering Moderate
Pest pressure Low
Daylight 14.7 hrs
  1. Transplant squash (summer) outside

    Pinch off the lowest leaves on each seedling before you plant — it reduces water loss while the roots catch up.

  2. Plant squash (summer) from seed, right in the garden

    These tolerate cool soil, so you're not gambling by sowing now.

Looking ahead to June
  • Starting indoors: squash (summer)

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Summer squash includes zucchini, yellow crookneck, and pattypan varieties that are harvested young and tender. They are prolific producers in warm weather.

Mille Lacs County, Minnesota is in USDA Zone 4a. The average last spring frost is May 1 and the first fall frost is October 6, giving you a growing season of approximately 158 days.

At an elevation of 874 feet, Mille Lacs County receives approximately 31.3 inches of rainfall annually with predominantly silt loam soil. Summer highs average 80°F, so choose short-season varieties of Squash (Summer) to ensure they mature before fall.

Mille Lacs County, MN (Zone 4a) Moderate season
158 days
Last Spring Frost May 1
158 growing days
First Fall Frost October 6
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Mille Lacs County Soil Profile

Soil Type

Silt Loam

Soil pH

5.9-7.3

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (23 days to spare)
Start indoors: Mar 14 Transplant: May 16 🍅 Harvest: Jul 4 – Sep 5
Recommended (50%) ✓ Fits season (25 days to spare)
Start indoors: Mar 20 Transplant: May 22 🍅 Harvest: Jul 10 – Sep 11
Safe Start (90%) ✓ Fits season (21 days to spare)
Start indoors: Apr 6 Transplant: Jun 8 🍅 Harvest: Jul 27 – Sep 28

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 Mille Lacs County

How your county's soil matches Squash (Summer)'s growing requirements.

Soil pH

Your soil pH (5.9–7.3) overlaps with Squash (Summer)'s range (6.0–7.5), though not a perfect match.

Soil Texture

The silt loam soil in Mille Lacs County is excellent for Squash (Summer) — good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is excellent (4.4%) — Squash (Summer) will thrive.

How to Plant Squash (Summer)

1"
Planting Depth
30"
Between Plants
42"
Between Rows

Succession Planting Squash (Summer)

4
successive plantings in your 158-day season

Sow every 5.1 weeks. Last sowing by Aug 02 to harvest before frost.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
0.8″/week
You supply
0.2″/week
Watering frequency Only during dry spells
Season total 236 gal / 100 sq ft

Monthly Watering Guide for Squash (Summer)

Squash (Summer) needs approximately 1 inches of water per week (4.3" per month). Here's how your county's rainfall compares month by month.

Month Squash (Summer) Needs Rainfall You Supplement Action
Jan 1.3" 0" ❄️ Dormant
Feb 1.6" 0" ❄️ Dormant
Mar 2.2" 0" ❄️ Dormant
Apr 3" 0" ❄️ Dormant
May 4.3" 3.3" 1" 💧 Light watering
Jun 4.3" 3.9" 0.4" 💧 Light watering
Jul 4.3" 3.6" 0.7" 💧 Light watering
Aug 4.3" 3.4" 0.9" 💧 Light watering
Sep 4.3" 2.9" 1.4" 💧 Light watering
Oct 4.3" 2.1" 2.2" 🚿 Regular watering
Nov 2.2" 0" ❄️ Dormant
Dec 1.9" 0" ❄️ Dormant

Water needs are for active growing months only (May–Oct in Mille Lacs County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.

Squash (Summer) 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.

Squash (Summer) needs ~550 GDD — county provides 1,580 GDD Excellent fit

Squash (Summer) Planting Timeline — Mille Lacs County, MN

Squash (Summer) Planting Calendar

Activity When Date Range
Start Indoors March 20 Mar 20 – Apr 3
Transplant Outdoors May 22 May 22 – Jun 5
Direct Sow May 15 May 15 – Jun 5
Harvest July 10 Jul 10 – Sep 11

Plant 1" deep · 30" apart · Rows 42" apart

Month-by-Month Timeline

MonthActivities
January
February
March Start Indoors
April Start Indoors
May Transplant Outdoors Direct Sow
June Transplant Outdoors Direct Sow
July Harvest
August Harvest
September Harvest
October
November
December
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Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1"/week · Only during dry spells

📅 Days to Maturity

45–65 days

🧪 Soil pH

Needs 6–7.5 · Your soil: acceptable

🗺️ USDA Zone

Zone 4a

📆 Growing Season

158 days in Mille Lacs County

Growing Tips for Squash (Summer) in Mille Lacs County

Direct sow Squash (Summer) outdoors after May 01 in Mille Lacs County when soil has warmed and frost danger has passed.

Common pests for Squash (Summer) 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 on mounds. Harvest frequently when fruits are 6-8 inches for best texture. Check plants daily as they grow rapidly in summer heat.

Companion Planting

Good Companions

Avoid Planting Near

  • Potatoes

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Squash (Summer) in Mille Lacs County, MN?

Mille Lacs County is in Zone 4a with an average last frost of May 1. Plan your Squash (Summer) planting based on this frost date — see the calendar above for exact timing.

What planting zone is Mille Lacs County, MN?

Mille Lacs County, Minnesota is in USDA Hardiness Zone 4a. The average last spring frost is May 1 and first fall frost is October 6.

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Your Mille Lacs County Garden Planner — Free

A 24-page printable planner built for Mille Lacs County (Zone 4a). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.

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Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for Mille Lacs County, MN. Local conditions may vary. Last updated: May 2026.

Sources & credits

Every number on this page traces back to a primary horticulture or government data source. Click through to verify.