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When to Plant Chard in Adams County, ID

Swiss chard is a colorful, heat-tolerant green with large crinkled leaves and vibrant stalks in red, yellow, and white. Both the leaves and stems are edible and nutritious.

Adams County, Idaho is in USDA Zone 5a. The average last spring frost is May 20 and the first fall frost is September 25, giving you a growing season of approximately 128 days.

At an elevation of 6,593 feet, Adams County receives approximately 20.6 inches of rainfall annually with predominantly loam soil. Summer highs average 85ยฐF, providing good warmth for Chard during the growing season.

Adams County, ID (Zone 5a) Short season
128 days
Last Spring Frost May 20
128 growing days
First Fall Frost September 25

Adams County Soil Profile

Soil Type

Loam

Soil pH

6.3-8

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (24 days to spare)
Start indoors: Mar 31 Transplant: May 5 🍅 Harvest: Jun 30 – Aug 18
Recommended (50%) ✓ Fits season (23 days to spare)
Start indoors: Apr 15 Transplant: May 20 🍅 Harvest: Jul 15 – Sep 2
Safe Start (90%) ✓ Fits season (19 days to spare)
Start indoors: May 19 Transplant: Jun 23 🍅 Harvest: Aug 18 – Oct 6

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
0.7″/week
You supply
0.8″/week
Watering frequency 2-3 times/week
Season total 853 gal / 100 sq ft
Drought risk

Water stress score is 8/10 โ€” consider drought-tolerant varieties and mulching

Chard needs ~756 GDD — county provides 1,760 GDD Excellent fit

Chard Planting Timeline โ€” Adams County, ID

Chard Planting Calendar

Activity When Date Range
Start Indoors April 15 Apr 15 โ€“ Apr 29
Transplant Outdoors May 20 May 20 โ€“ Jun 3
Direct Sow May 6 May 6 โ€“ May 27
Fall Sowing July 17 Jul 17 โ€“ Jul 31
Harvest July 15 Jul 15 โ€“ Sep 2

Plant 1" deep ยท 15" apart ยท Rows 24" apart

Month-by-Month Timeline

MonthActivities
January โ€”
February โ€”
March โ€”
April Start Indoors
May Transplant Outdoors Direct Sow
June Transplant Outdoors
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

50โ€“60 days

Soil pH

6 โ€“ 7

USDA Zone

Zone 5a

Growing Season

128 days

Growing Tips for Adams County

Direct sow or transplant after last frost. Harvest outer leaves regularly to encourage continuous production. Chard tolerates both heat and light frost.

Companion Planting

Good Companions

Avoid Planting Near

  • Corn
  • Cucumbers

Level Up Your Garden

Frequently Asked Questions

When should I plant Chard in Adams County, ID?

Adams County is in Zone 5a with an average last frost of May 20. Plan your Chard planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Adams County, ID?

Adams County, Idaho is in USDA Hardiness Zone 5a. The average last spring frost is May 20 and first fall frost is September 25.

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Plan Your Garden with Confidence

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

Get Your Free Garden Planner →

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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 Adams County, ID. Local conditions may vary. Last updated: April 2026.