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When to Plant Squash (Summer) in Blaine County, ID

Blaine County, Idaho Zone 5b May

Your May planting checklist for Blaine County, Idaho

Welcome to May in Zone 5b. These are the moves that will have the biggest impact on your growing season.

Avg. last frost May 18
Avg. first frost October 3
Soil temp (4") 35°F
Watering High
Pest pressure Low
Daylight 14.5 hrs
  1. Seed squash (summer) outdoors

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

June will be here before you know it — start on
  • Transplants going out: squash (summer)
  • 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.

Blaine County, Idaho is in USDA Zone 5b. The average last spring frost is May 18 and the first fall frost is October 3, giving you a growing season of approximately 138 days.

At an elevation of 7,128 feet, Blaine County receives approximately 17.7 inches of rainfall annually with predominantly loam soil. Summer highs average 84°F, so choose short-season varieties of Squash (Summer) to ensure they mature before fall. With low rainfall, drip irrigation is essential for growing Squash (Summer) successfully. Mulch heavily to conserve soil moisture.

Blaine County, ID (Zone 5b) Short season
138 days
Last Spring Frost May 18
138 growing days
First Fall Frost October 3

Blaine County Soil Profile

Soil Type

Loam

Soil pH

6.7-8.4

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (15 days to spare)
Start indoors: Apr 1 Transplant: May 20 🍅 Harvest: Jul 8 – Sep 9
Recommended (50%) ✓ Fits season (12 days to spare)
Start indoors: Apr 13 Transplant: Jun 1 🍅 Harvest: Jul 20 – Sep 21
Safe Start (90%) ✓ Fits season (5 days to spare)
Start indoors: May 7 Transplant: Jun 25 🍅 Harvest: Aug 13 – 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 Blaine County

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

Soil pH

Your soil pH (6.7–8.4) is more alkaline than Squash (Summer) prefers (6.0–7.5). Add sulfur or peat moss to lower pH.

Soil Texture

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

Drainage

Drainage is adequate for Squash (Summer).

Organic Matter

Organic matter is moderate (2.2%). Annual compost additions will help Squash (Summer).

How to Plant Squash (Summer)

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

Succession Planting Squash (Summer)

3
successive plantings in your 138-day season

Sow every 5.1 weeks. Last sowing by Jul 30 to harvest before frost.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
0.5″/week
You supply
0.9″/week
Watering frequency 2-3 times/week
Season total 1,122 gal / 100 sq ft
Drought risk

Water stress score is 8/10 — consider drought-tolerant varieties and mulching

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 1.4" 0" ❄️ Dormant
Feb 0.9" 0" ❄️ Dormant
Mar 1.5" 0" ❄️ Dormant
Apr 1.7" 0" ❄️ Dormant
May 4.3" 1.9" 2.4" 🚿 Regular watering
Jun 4.3" 1.2" 3.1" 🚿 Regular watering
Jul 4.3" 1.8" 2.5" 🚿 Regular watering
Aug 4.3" 2.2" 2.1" 💧 Light watering
Sep 4.3" 1.5" 2.8" 🚿 Regular watering
Oct 4.3" 1.4" 2.9" 🚿 Regular watering
Nov 1.3" 0" ❄️ Dormant
Dec 1" 0" ❄️ Dormant

Water needs are for active growing months only (May–Oct in Blaine 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 ~715 GDD — county provides 1,794 GDD Excellent fit

Squash (Summer) Planting Timeline — Blaine County, ID

Squash (Summer) Planting Calendar

Activity When Date Range
Start Indoors April 13 Apr 13 – Apr 27
Transplant Outdoors June 1 Jun 1 – Jun 15
Direct Sow May 25 May 25 – Jun 15
Harvest July 20 Jul 20 – Sep 21

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

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1"/week · 2-3 times/week

📅 Days to Maturity

45–65 days

🧪 Soil pH

Needs 6–7.5 · Your soil: too_alkaline

🗺️ USDA Zone

Zone 5b

📆 Growing Season

138 days in Blaine County

Growing Tips for Squash (Summer) in Blaine County

Direct sow Squash (Summer) outdoors after May 18 in Blaine 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.

Blaine County receives only 18" of rain annually. Squash (Summer) needs consistent moisture — install drip irrigation or water deeply 2-3 times per week.

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 Blaine County, ID?

Blaine County is in Zone 5b with an average last frost of May 18. Plan your Squash (Summer) planting based on this frost date — see the calendar above for exact timing.

What planting zone is Blaine County, ID?

Blaine County, Idaho is in USDA Hardiness Zone 5b. The average last spring frost is May 18 and first fall frost is October 3.

🌱

Your Blaine County Garden Planner — Free

A 24-page printable planner built for Blaine 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.

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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 Blaine 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.