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When to Plant Acorn Squash in Spink County, SD

Spink County, South Dakota Zone 4b May

Your May game plan for Spink County, South Dakota

Your Spink County, South Dakota garden is entering a new phase. Here's what's on the schedule for May and why each task matters now.

Avg. last frost May 10
Avg. first frost October 1
Soil temp (4") 56°F
Watering Low
Pest pressure Low
Daylight 14.6 hrs
  1. Get acorn squash in the ground

    Water the tray well an hour before you transplant. Roots slide out cleanly and settle in faster.

  2. Direct-sow acorn squash

    Keep the top inch of soil moist until germination — a gentle morning watering for 5–7 days does the job.

June will be here before you know it — start on
  • Starting indoors: acorn squash

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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.

Spink County, South Dakota is in USDA Zone 4b. The average last spring frost is May 10 and the first fall frost is October 1, giving you a growing season of approximately 144 days.

At an elevation of 818 feet, Spink County receives approximately 31.4 inches of rainfall annually with predominantly loam soil. Summer highs average 81°F, so choose short-season varieties of Acorn Squash to ensure they mature before fall.

Spink County, SD (Zone 4b) Short season
144 days
Last Spring Frost May 10
144 growing days
First Fall Frost October 1
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Spink County Soil Profile

Soil Type

Loam

Soil pH

6.7-7.3

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (5 days to spare)
Start indoors: Mar 20 Transplant: May 22 🍅 Harvest: Aug 14 – Sep 18
Recommended (50%) ✓ Fits season (4 days to spare)
Start indoors: Mar 29 Transplant: May 31 🍅 Harvest: Aug 23 – Sep 27
Safe Start (90%) ✓ Fits season (6 days to spare)
Start indoors: Apr 7 Transplant: Jun 9 🍅 Harvest: Sep 1 – Oct 6

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 Spink County

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

Soil pH

Your soil pH (6.7–7.3) overlaps with Acorn Squash's range (5.5–7.0), though not a perfect match.

Soil Texture

The loam soil in Spink 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 moderate (3.4%). 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 144-day season

Sow every 9.1 weeks. Last sowing by Jun 23 to harvest before frost.

Plant Water Budget

Plant needs
1.1″/week
Rainfall provides
0.9″/week
You supply
0.6″/week
Watering frequency 1-2 times/week
Season total 791 gal / 100 sq ft
Drought risk

Water stress score is 6/10 — consider drought-tolerant varieties and mulching

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 0.9" 0" ❄️ Dormant
Feb 1.1" 0" ❄️ Dormant
Mar 2.2" 0" ❄️ Dormant
Apr 2.9" 0" ❄️ Dormant
May 4.8" 5.3" 0" ✅ Rainfall sufficient
Jun 4.8" 4.5" 0.3" 💧 Light watering
Jul 4.8" 3.6" 1.2" 💧 Light watering
Aug 4.8" 4.1" 0.7" 💧 Light watering
Sep 4.8" 2.7" 2.1" 💧 Light watering
Oct 4.8" 2.3" 2.5" 🚿 Regular watering
Nov 1" 0" ❄️ Dormant
Dec 0.8" 0" ❄️ Dormant

Water needs are for active growing months only (May–Oct in Spink 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 ~968 GDD — county provides 1,548 GDD Excellent fit

Acorn Squash Planting Timeline — Spink County, SD

Acorn Squash Planting Calendar

Activity When Date Range
Start Indoors March 29 Mar 29 – Apr 12
Transplant Outdoors May 31 May 31 – Jun 14
Direct Sow May 24 May 24 – Jun 14
Harvest August 23 Aug 23 – Sep 27

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
August Harvest
September Harvest
October
November
December
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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: acceptable

🗺️ USDA Zone

Zone 4b

📆 Growing Season

144 days in Spink County

Growing Tips for Acorn Squash in Spink County

Direct sow Acorn Squash outdoors after May 10 in Spink 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 Spink County, SD?

Spink County is in Zone 4b with an average last frost of May 10. Plan your Acorn Squash planting based on this frost date — see the calendar above for exact timing.

What planting zone is Spink County, SD?

Spink County, South Dakota is in USDA Hardiness Zone 4b. The average last spring frost is May 10 and first fall frost is October 1.

🌱

Your Spink County Garden Planner — Free

A 24-page printable planner built for Spink County (Zone 4b). 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 Spink County, SD. 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.