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When to Plant Mustard Greens in Idaho County, ID

Mustard greens are fast-growing brassicas with a spicy, peppery kick. They come in green, red, and purple varieties and are excellent cooked or in salads.

Idaho County, Idaho is in USDA Zone 5a. The average last spring frost is May 29 and the first fall frost is September 20, giving you a growing season of approximately 114 days.

At an elevation of 6,736 feet, Idaho County receives approximately 24.5 inches of rainfall annually with predominantly loam soil. Summer highs average 84ยฐF, so choose short-season varieties of Mustard Greens to ensure they mature before fall.

Idaho County, ID (Zone 5a) Short season
114 days
Last Spring Frost May 29
114 growing days
First Fall Frost September 20

Idaho County Soil Profile

Soil Type

Loam

Soil pH

6.3-7.8

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (7 days to spare)
Start indoors: Apr 13 Transplant: May 18 🍅 Harvest: Jun 22 – Aug 24
Recommended (50%) ✓ Fits season (16 days to spare)
Start indoors: Apr 24 Transplant: May 29 🍅 Harvest: Jul 3 – Sep 4
Safe Start (90%) ✓ Fits season (9 days to spare)
Start indoors: May 20 Transplant: Jun 24 🍅 Harvest: Jul 29 – Sep 30

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
0.9″/week
You supply
0.1″/week
Watering frequency Only during dry spells
Season total 119 gal / 100 sq ft
Drought risk

Water stress score is 6/10 โ€” consider drought-tolerant varieties and mulching

Mustard Greens needs ~520 GDD — county provides 1,482 GDD Excellent fit

Mustard Greens Planting Timeline โ€” Idaho County, ID

Mustard Greens Planting Calendar

Activity When Date Range
Start Indoors April 24 Apr 24 โ€“ May 8
Transplant Outdoors May 29 May 29 โ€“ Jun 12
Direct Sow May 15 May 15 โ€“ Jun 5
Fall Sowing July 12 Jul 12 โ€“ Jul 26
Harvest July 3 Jul 3 โ€“ Sep 4

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

Month-by-Month Timeline

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

Growing Conditions

Sun

Partial Shade (3-6 hours)

Water

Moderate โ€” regular watering

Days to Maturity

30โ€“50 days

Soil pH

6 โ€“ 7

USDA Zone

Zone 5a

Growing Season

114 days

Growing Tips for Idaho County

Direct sow in early spring or fall. Harvest young leaves for milder flavor. Plants bolt quickly in heat so grow as a cool-season crop or provide shade.

Companion Planting

Good Companions

Avoid Planting Near

  • Strawberries

Level Up Your Garden

Frequently Asked Questions

When should I plant Mustard Greens in Idaho County, ID?

Idaho County is in Zone 5a with an average last frost of May 29. Plan your Mustard Greens planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Idaho County, ID?

Idaho County, Idaho is in USDA Hardiness Zone 5a. The average last spring frost is May 29 and first fall frost is September 20.

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Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Idaho 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 Idaho County, ID. Local conditions may vary. Last updated: April 2026.