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When to plant Spinach in Treasure County, MT

In Treasure County, plant Spinach in spring between May 4 and May 25, once soil temps hold above 50°F. Treasure County's last frost averages May 11, so be cautious and check the 10-day forecast before planting tender crops. For a fall crop, sow between July 9 and July 23 — roughly 35–50 days before the first frost on October 1.

When to Plant Spinach in Treasure County, MT

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.

Treasure County, Montana is in USDA Zone 4b. The average last spring frost is May 11 and the first fall frost is October 1, giving you a growing season of approximately 143 days.

At an elevation of 6,726 feet, Treasure County receives approximately 17.1 inches of rainfall annually with predominantly loam soil. Summer highs average 84°F, so choose short-season varieties of Spinach to ensure they mature before fall. With low rainfall, drip irrigation is essential for growing Spinach successfully. Mulch heavily to conserve soil moisture.

Treasure County, MT (Zone 4b) Short season
143 days
Last Spring Frost May 11
143 growing days
First Fall Frost October 1

Treasure County Soil Profile

Soil Type

Loam

Soil pH

6.0-7.0

Drainage

Well Drained

Spinach Planting Timeline — Treasure County, MT

Spinach Planting Calendar

Activity When Date Range
Start Indoors March 30 Mar 30 – Apr 13
Transplant Outdoors May 11 May 11 – May 25
Direct Sow May 4 May 4 – May 25
Harvest June 15 Jun 15 – Aug 17
Fall Sowing July 9 Jul 9 – Jul 23

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

Month-by-Month Timeline

MonthActivities
January
February
March Start Indoors
April Start Indoors
May Transplant Outdoors Direct Sow
June Harvest
July Fall Sowing Harvest
August Harvest
September
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 4b

📆 Growing Season

143 days in Treasure County

Growing Tips for Treasure 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 Treasure County, MT?

Treasure County is in Zone 4b with an average last frost of May 11. Plan your Spinach planting based on this frost date — see the calendar above for exact timing.

What planting zone is Treasure County, MT?

Treasure County, Montana is in USDA Hardiness Zone 4b. The average last spring frost is May 11 and first fall frost is October 1.

When should I plant Spinach in Treasure County, MT?

In Treasure County, MT, plant Spinach after the last frost (around May 11) and before the first frost (around October 1). Best results when soil holds above 50°F.

What growing zone is Treasure County, MT for Spinach?

Treasure County sits in USDA Zone 4b. Spinach grows reliably in zones 2a through 10b, so it's a good fit here.

Can Spinach grow in Treasure County's climate?

Yes — Spinach grows well in Treasure County's temperate climate. Treasure County averages a 143-day frost-free season, with last frost around May 11 and first frost around October 1.

🌱

Your Treasure County Garden Planner — Free

A 22-page printable planner built for Treasure 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 Treasure County, MT. Local conditions may vary. Last updated: June 2026.

Sources & credits

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