When to Plant Chard in Boundary 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.
Boundary County, Idaho is in USDA Zone 5b. The average last spring frost is May 10 and the first fall frost is September 22, giving you a growing season of approximately 135 days.
At an elevation of 5,105 feet, Boundary County receives approximately 21.1 inches of rainfall annually with predominantly loam soil. Summer highs average 87°F, providing good warmth for Chard during the growing season.
Boundary County Soil Profile
Soil Type
Loam
Soil pH
6.7-8.3
Drainage
Well Drained
Plant Planting Risk Windows
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
Water stress score is 6/10 — consider drought-tolerant varieties and mulching
Chard Planting Timeline — Boundary County, ID
Chard Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | April 5 | Apr 5 – Apr 19 |
| Transplant Outdoors | May 10 | May 10 – May 24 |
| Direct Sow | April 26 | Apr 26 – May 17 |
| Fall Sowing | July 14 | Jul 14 – Jul 28 |
| Harvest | July 5 | Jul 5 – Aug 23 |
Plant 1" deep · 15" apart · Rows 24" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | — |
| April | Start Indoors Direct Sow |
| May | Transplant Outdoors Direct Sow |
| June | — |
| 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
50–60 days
Soil pH
6 – 7
USDA Zone
Zone 5b
Growing Season
135 days
Growing Tips for Boundary 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
Level Up Your Garden
Chard in Other Locations
Frequently Asked Questions
When should I plant Chard in Boundary County, ID?
Boundary County is in Zone 5b with an average last frost of May 10. Plan your Chard planting based on this frost date — see the calendar above for exact timing.
What planting zone is Boundary County, ID?
Boundary County, Idaho is in USDA Hardiness Zone 5b. The average last spring frost is May 10 and first fall frost is September 22.
Plan Your Garden with Confidence
Get our free Garden Planner — designed to help Boundary County gardeners in Zone 5b organize planting dates, track what's growing, and never miss a planting window.
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