When to Plant Amaranth in San Juan County, CO
Amaranth is an ancient grain crop with edible leaves and seeds, rich in protein and micronutrients. It thrives in warm conditions and is drought-tolerant once established.
San Juan County, Colorado is in USDA Zone 4a. The average last spring frost is June 18 and the first fall frost is September 8, giving you a growing season of approximately 82 days.
At an elevation of 7,539 feet, San Juan County receives approximately 20.1 inches of rainfall annually with predominantly loam soil. Summer highs average 82°F, so choose short-season varieties of Amaranth to ensure they mature before fall.
San Juan County Soil Profile
Soil Type
Loam
Soil pH
6.3-8
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
Amaranth Planting Timeline — San Juan County, CO
Amaranth Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | April 16 | Apr 16 – Apr 30 |
| Transplant Outdoors | July 9 | Jul 9 – Jul 23 |
| Direct Sow | July 2 | Jul 2 – Jul 23 |
| Harvest | October 8 | Oct 8 – Nov 26 |
Plant 1" deep · 15" apart · Rows 24" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | — |
| April | Start Indoors |
| May | — |
| June | — |
| July | Transplant Outdoors Direct Sow |
| August | — |
| September | — |
| October | Harvest |
| November | Harvest |
| December | — |
Growing Conditions
Sun
Full Sun (6-8+ hours)
Water
Moderate — regular watering
Days to Maturity
90–120 days
Soil pH
6 – 7.5
USDA Zone
Zone 4a
Growing Season
82 days
Growing Tips for San Juan County
Direct sow after last frost when soil is warm. Thin seedlings to 18 inches apart. Harvest leaves when young and tender; harvest seeds when flower heads begin to dry.
Companion Planting
Good Companions
Avoid Planting Near
Level Up Your Garden
Amaranth in Other Locations
Frequently Asked Questions
When should I plant Amaranth in San Juan County, CO?
San Juan County is in Zone 4a with an average last frost of June 18. Plan your Amaranth planting based on this frost date — see the calendar above for exact timing.
What planting zone is San Juan County, CO?
San Juan County, Colorado is in USDA Hardiness Zone 4a. The average last spring frost is June 18 and first fall frost is September 8.
Plan Your Garden with Confidence
Get our free Garden Planner — designed to help San Juan County gardeners in Zone 4a organize planting dates, track what's growing, and never miss a planting window.
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