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When to Plant Acorn Squash in Jerome County, ID

Jerome County, Idaho Zone 6b May

Your May gardening checklist

Your garden in Jerome County, Idaho is working on a schedule, even when you're not. Here's where you should be this May.

Avg. last frost May 10
Avg. first frost October 4
Soil temp (4") 44°F
Watering High
Pest pressure Low
Daylight 14.4 hrs
  1. Move acorn squash into the garden

    Bring a watering can to the bed. Each transplant gets a drink the moment it's in the ground, not ten minutes later.

  2. Plant acorn squash from seed, right in the garden

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

Coming up in June — start thinking about
  • 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.

Jerome County, Idaho is in USDA Zone 6b. The average last spring frost is May 10 and the first fall frost is October 4, giving you a growing season of approximately 147 days.

At an elevation of 6,306 feet, Jerome County receives approximately 13.5 inches of rainfall annually with predominantly loam soil. Summer highs average 85°F, providing good warmth for Acorn Squash during the growing season. With low rainfall, drip irrigation is essential for growing Acorn Squash successfully. Mulch heavily to conserve soil moisture.

Jerome County, ID (Zone 6b) Short season
147 days
Last Spring Frost May 10
147 growing days
First Fall Frost October 4

Jerome County Soil Profile

Soil Type

Loam

Soil pH

6.8-7.9

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (17 days to spare)
Start indoors: Mar 27 Transplant: May 15 🍅 Harvest: Aug 7 – Sep 11
Recommended (50%) ✓ Fits season (14 days to spare)
Start indoors: Apr 5 Transplant: May 24 🍅 Harvest: Aug 16 – Sep 20
Safe Start (90%) ✓ Fits season (7 days to spare)
Start indoors: Apr 30 Transplant: Jun 18 🍅 Harvest: Sep 10 – Oct 15

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 Jerome County

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

Soil pH

Your soil pH (6.8–7.9) is more alkaline than Acorn Squash prefers (5.5–7.0). Add sulfur or peat moss to lower pH.

Soil Texture

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

Organic Matter

Organic matter is moderate (2.8%). 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 147-day season

Sow every 9.1 weeks. Last sowing by Jun 26 to harvest before frost.

Plant Water Budget

Plant needs
1.1″/week
Rainfall provides
0.4″/week
You supply
0.9″/week
Watering frequency 2-3 times/week
Season total 1,121 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 1" 0" ❄️ Dormant
Feb 0.8" 0" ❄️ Dormant
Mar 1.3" 0" ❄️ Dormant
Apr 1.6" 0" ❄️ Dormant
May 4.8" 1.5" 3.3" 🚿 Regular watering
Jun 4.8" 1" 3.8" 🚿 Regular watering
Jul 4.8" 1.2" 3.6" 🚿 Regular watering
Aug 4.8" 1.3" 3.5" 🚿 Regular watering
Sep 4.8" 1.1" 3.7" 🚿 Regular watering
Oct 4.8" 1.1" 3.7" 🚿 Regular watering
Nov 0.8" 0" ❄️ Dormant
Dec 0.8" 0" ❄️ Dormant

Water needs are for active growing months only (May–Oct in Jerome 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 ~1,238 GDD — county provides 2,021 GDD Excellent fit

Acorn Squash Planting Timeline — Jerome County, ID

Acorn Squash Planting Calendar

Activity When Date Range
Start Indoors April 5 Apr 5 – Apr 19
Transplant Outdoors May 24 May 24 – Jun 7
Direct Sow May 17 May 17 – Jun 7
Harvest August 16 Aug 16 – Sep 20

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

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1.1"/week · 2-3 times/week

📅 Days to Maturity

80–100 days

🧪 Soil pH

Needs 5.5–7 · Your soil: too_alkaline

🗺️ USDA Zone

Zone 6b

📆 Growing Season

147 days in Jerome County

Growing Tips for Acorn Squash in Jerome County

Direct sow Acorn Squash outdoors after May 10 in Jerome 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.

Jerome County receives only 14" of rain annually. Acorn Squash needs consistent moisture — install drip irrigation or water deeply 2-3 times per week.

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 Jerome County, ID?

Jerome County is in Zone 6b 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 Jerome County, ID?

Jerome County, Idaho is in USDA Hardiness Zone 6b. The average last spring frost is May 10 and first fall frost is October 4.

🌱

Your Jerome County Garden Planner — Free

A 24-page printable planner built for Jerome County (Zone 6b). 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 Jerome County, ID. 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.