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When to plant Spinach in Custer County, ID

Spring Spinach in Custer County goes in June 4–June 25, once nighttime temps stop dipping near freezing. A second sowing from June 27 to July 11 extends the harvest into fall.

When to Plant Spinach in Custer County, ID

Spinach

Spinach is a nutrient-packed cool-season green that grows quickly in spring and fall. It is rich in iron, vitamins, and antioxidants and excellent raw or cooked.

Custer County, Idaho is in USDA Zone 5b. The average last spring frost is June 18 and the first fall frost is September 5, giving you a growing season of approximately 79 days.

At an elevation of 5,189 feet, Custer County receives approximately 20.6 inches of rainfall annually with predominantly loam soil. Summer highs average 80°F, so choose short-season varieties of Spinach to ensure they mature before fall.

Custer County, ID (Zone 5b) Very short season
79 days
Last Spring Frost June 18
79 growing days
First Fall Frost September 5

Custer County Soil Profile

Soil Type

Loam

Soil pH

6.0-7.0

Drainage

Well Drained

Spinach Planting Timeline — Custer County, ID

Spinach Planting Calendar

Activity When Date Range
Start Indoors May 14 May 14 – May 28
Transplant Outdoors June 18 Jun 18 – Jul 2
Direct Sow June 4 Jun 4 – Jun 25
Harvest July 23 Jul 23 – Sep 24
Fall Sowing June 27 Jun 27 – Jul 11

Plant 0.5" deep · 6" apart · Rows 12" apart

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Partial Shade (3-6 hours)

💧 Water

Moderate — regular watering

📅 Days to Maturity

35–50 days

🧪 Soil pH

Needs 6.5–7.5 · Your soil: N/A

🗺️ USDA Zone

Zone 5b

📆 Growing Season

79 days in Custer County

Growing Tips for Custer County

Direct sow as soon as soil can be worked in spring. Plant in partial shade for summer crops to delay bolting. Succession plant every 2 weeks for continuous harvest.

Companion Planting

Good Companions

Check more plant combinations with our Companion Planting Checker →

🌾 Save Your Own Spinach Seeds
Life Cycle Annual
Pollination Wind Pollinated
How to Collect Let plants bolt. Harvest seed stalks when seeds turn tan.
Storage Store airtight; viable 5 years at 35°F, under 45% humidity.

Wind pollinated — isolate 1/2 mile for purity. Easy to let bolt in heat.

Frequently Asked Questions

When should I plant Spinach in Custer County, ID?

Custer County is in Zone 5b with an average last frost of June 18. Plan your Spinach planting based on this frost date — see the calendar above for exact timing.

What planting zone is Custer County, ID?

Custer County, Idaho is in USDA Hardiness Zone 5b. The average last spring frost is June 18 and first fall frost is September 5.

When should I plant Spinach in Custer County, ID?

In Custer County, ID, plant Spinach after the last frost (around June 18) and before the first frost (around September 5). Best results when soil holds above 50°F.

What growing zone is Custer County, ID for Spinach?

Custer County sits in USDA Zone 5b. Spinach grows reliably in zones 2a through 10b, so it's a good fit here.

Can Spinach grow in Custer County's climate?

Yes — Spinach grows well in Custer County's temperate climate. Custer County averages a 79-day frost-free season, with last frost around June 18 and first frost around September 5.

🌱

Your Custer County Garden Planner — Free

A 22-page printable planner built for Custer 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 Custer County, ID. Local conditions may vary. Last updated: July 2026.

Sources & credits

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