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When to Plant Acorn Squash in Clark County, MO

Clark County, Missouri Zone 6a May

May in Clark County, Missouri — your action list

We've pulled the most time-sensitive tasks for Clark County, Missouri this May and put them front and centre. Tackle them in order.

Avg. last frost April 16
Avg. first frost October 18
Soil temp (4") 60°F
Watering Low
Pest pressure Low
Daylight 14.2 hrs
  1. Sow acorn squash in trays indoors

    These need a head start before your last frost (April 16). Sow into cells now so you're ready to transplant in a few weeks.

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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.

Clark County, Missouri is in USDA Zone 6a. The average last spring frost is April 16 and the first fall frost is October 18, giving you a growing season of approximately 185 days.

At an elevation of 833 feet, Clark County receives approximately 33 inches of rainfall annually with predominantly silt loam soil. Summer highs average 87°F, providing good warmth for Acorn Squash during the growing season.

Clark County, MO (Zone 6a) Moderate season
185 days
Last Spring Frost April 16
185 growing days
First Fall Frost October 18

Clark County Soil Profile

Soil Type

Silt Loam

Soil pH

5.6-6.6

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (52 days to spare)
Start indoors: Mar 6 Transplant: Apr 24 🍅 Harvest: Jul 17 – Aug 21
Recommended (50%) ✓ Fits season (52 days to spare)
Start indoors: Mar 12 Transplant: Apr 30 🍅 Harvest: Jul 23 – Aug 27
Safe Start (90%) ✓ Fits season (48 days to spare)
Start indoors: Mar 28 Transplant: May 16 🍅 Harvest: Aug 8 – Sep 12

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 Clark County

How your county's soil matches Acorn Squash's growing requirements.

Soil pH

Your soil pH (5.6–6.6) is within Acorn Squash's preferred range (5.5–7.0).

Soil Texture

The silt loam soil in Clark County is excellent for Acorn Squash — good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is moderate (2.6%). Annual compost additions will help Acorn Squash.

How to Plant Acorn Squash

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

Succession Planting Acorn Squash

2
successive plantings in your 185-day season

Sow every 9.1 weeks. Last sowing by Jul 10 to harvest before frost.

Plant Water Budget

Plant needs
1.1″/week
Rainfall provides
0.8″/week
You supply
0.4″/week
Watering frequency 1-2 times/week
Season total 578 gal / 100 sq ft

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 1.4" 0" ❄️ Dormant
Feb 1.4" 0" ❄️ Dormant
Mar 1.9" 0" ❄️ Dormant
Apr 4.8" 3.3" 1.5" 💧 Light watering
May 4.8" 4.1" 0.7" 💧 Light watering
Jun 4.8" 3.7" 1.1" 💧 Light watering
Jul 4.8" 3.3" 1.5" 💧 Light watering
Aug 4.8" 3.7" 1.1" 💧 Light watering
Sep 4.8" 3.2" 1.6" 💧 Light watering
Oct 4.8" 2.6" 2.2" 💧 Light watering
Nov 2.5" 0" ❄️ Dormant
Dec 1.8" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Clark 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 needs ~1,372 GDD — county provides 2,821 GDD Excellent fit

Acorn Squash Planting Timeline — Clark County, MO

Acorn Squash Planting Calendar

Activity When Date Range
Start Indoors March 12 Mar 12 – Mar 26
Transplant Outdoors April 30 Apr 30 – May 14
Direct Sow April 23 Apr 23 – May 14
Harvest July 23 Jul 23 – Aug 27

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

Month-by-Month Timeline

MonthActivities
January
February
March Start Indoors
April Transplant Outdoors Direct Sow
May Transplant Outdoors Direct Sow
June
July Harvest
August Harvest
September
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 6a

📆 Growing Season

185 days in Clark County

Growing Tips for Acorn Squash in Clark County

Direct sow Acorn Squash outdoors after April 16 in Clark 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

  • Potatoes

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Acorn Squash in Clark County, MO?

Clark County is in Zone 6a with an average last frost of April 16. Plan your Acorn Squash planting based on this frost date — see the calendar above for exact timing.

What planting zone is Clark County, MO?

Clark County, Missouri is in USDA Hardiness Zone 6a. The average last spring frost is April 16 and first fall frost is October 18.

🌱

Your Clark County Garden Planner — Free

A 24-page printable planner built for Clark County (Zone 6a). 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 Clark County, MO. 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.