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When to Plant New Zealand Spinach in Blaine County, ID

New Zealand spinach is a heat-tolerant ground-cover plant with thick, triangular leaves that taste similar to true spinach. It thrives in hot weather when regular spinach bolts.

Blaine County, Idaho is in USDA Zone 5a. 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 84ยฐF, so choose short-season varieties of New Zealand Spinach to ensure they mature before fall. With low rainfall, drip irrigation is essential for growing New Zealand Spinach successfully. Mulch heavily to conserve soil moisture.

Blaine County, ID (Zone 5a) 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 (43 days to spare)
Start indoors: Mar 11 Transplant: May 20 🍅 Harvest: Jul 15 – Aug 12
Recommended (50%) ✓ Fits season (40 days to spare)
Start indoors: Mar 23 Transplant: Jun 1 🍅 Harvest: Jul 27 – Aug 24
Safe Start (90%) ✓ Fits season (33 days to spare)
Start indoors: Apr 16 Transplant: Jun 25 🍅 Harvest: Aug 20 – Sep 17

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.

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 โ€” consider drought-tolerant varieties and mulching

New Zealand Spinach needs ~812 GDD — county provides 1,794 GDD Excellent fit

New Zealand Spinach Planting Timeline โ€” Blaine County, ID

New Zealand Spinach Planting Calendar

Activity When Date Range
Start Indoors March 23 Mar 23 โ€“ Apr 6
Transplant Outdoors June 1 Jun 1 โ€“ Jun 15
Direct Sow May 25 May 25 โ€“ Jun 15
Harvest July 27 Jul 27 โ€“ Aug 24

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

Month-by-Month Timeline

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

Growing Conditions

Sun

Full Sun (6-8+ hours)

Water

Moderate โ€” regular watering

Days to Maturity

55โ€“70 days

Soil pH

6 โ€“ 7.5

USDA Zone

Zone 5a

Growing Season

138 days

Growing Tips for Blaine County

Soak seeds overnight before planting. Direct sow after last frost. Pinch growing tips regularly to encourage bushy growth and tender new leaves.

Companion Planting

Good Companions

Level Up Your Garden

Frequently Asked Questions

When should I plant New Zealand Spinach in Blaine County, ID?

Blaine County is in Zone 5a with an average last frost of May 18. Plan your New Zealand Spinach planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Blaine County, ID?

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

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Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Blaine County gardeners in Zone 5a organize planting dates, track what's growing, and never miss a planting window.

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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: April 2026.