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When to Plant Amaranth in Eagle 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.

Eagle County, Colorado is in USDA Zone 4b. The average last spring frost is June 16 and the first fall frost is September 7, giving you a growing season of approximately 83 days.

At an elevation of 7,116 feet, Eagle County receives approximately 24.5 inches of rainfall annually with predominantly loam soil. Summer highs average 81ยฐF, so choose short-season varieties of Amaranth to ensure they mature before fall.

Eagle County, CO (Zone 4b) Very short season
83 days
Last Spring Frost June 16
83 growing days
First Fall Frost September 7

Eagle County Soil Profile

Soil Type

Loam

Soil pH

6.6-7.7

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Start indoors: Apr 3 Transplant: Jun 26 🍅 Harvest: Sep 25 – Nov 13
Recommended (50%) ✗ May not fit
Start indoors: Apr 14 Transplant: Jul 7 🍅 Harvest: Oct 6 – Nov 24
Safe Start (90%) ✗ May not fit
Start indoors: Apr 25 Transplant: Jul 18 🍅 Harvest: Oct 17 – Dec 5

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.

Soil Compatibility in Eagle County

How your county's soil matches Amaranth's growing requirements.

Soil pH

Your soil pH (6.6โ€“7.7) overlaps with Amaranth's range (6.0โ€“7.5), though not a perfect match.

Soil Texture

The loam soil in Eagle County is excellent for Amaranth โ€” good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is moderate (2.2%). Annual compost additions will help Amaranth.

How to Plant Amaranth

1"
Planting Depth
15"
Between Plants
24"
Between Rows

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
1.2″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft
Drought risk

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

Monthly Watering Guide for Amaranth

Amaranth needs approximately 1 inches of water per week (4.3" per month). Here's how your county's rainfall compares month by month.

Month Amaranth Needs Rainfall You Supplement Action
Jan โ€” 1.8" 0" โ„๏ธ Dormant
Feb โ€” 1.2" 0" โ„๏ธ Dormant
Mar โ€” 2.4" 0" โ„๏ธ Dormant
Apr โ€” 2.8" 0" โ„๏ธ Dormant
May โ€” 3.2" 0" โ„๏ธ Dormant
Jun 4.3" 1.6" 2.7" ๐Ÿšฟ Regular watering
Jul 4.3" 2.1" 2.2" ๐Ÿšฟ Regular watering
Aug 4.3" 2.4" 1.9" ๐Ÿ’ง Light watering
Sep 4.3" 1.8" 2.5" ๐Ÿšฟ Regular watering
Oct โ€” 2" 0" โ„๏ธ Dormant
Nov โ€” 1.6" 0" โ„๏ธ Dormant
Dec โ€” 1.5" 0" โ„๏ธ Dormant

Water needs are for active growing months only (Junโ€“Sep in Eagle County). Supplement amounts are based on average rainfall โ€” actual needs vary with temperature, soil, and mulching.

Amaranth Heat Requirements (GDD)

What are Growing Degree Days (GDD)?

Growing Degree Days measure the total warmth your plants receive during the growing season. Think of it as a "heat bank" โ€” every day above 50ยฐF deposits warmth that helps your plants grow.

Each plant needs a certain amount of accumulated heat to mature. If your county provides more GDD than the plant needs, it's a great fit. If it's close, you may want to choose faster-maturing varieties or start seeds indoors to get a head start.

Amaranth needs ~1,129 GDD — county provides 892 GDD May not mature

Amaranth Planting Timeline โ€” Eagle County, CO

Amaranth Planting Calendar

Activity When Date Range
Start Indoors April 14 Apr 14 โ€“ Apr 28
Transplant Outdoors July 7 Jul 7 โ€“ Jul 21
Direct Sow June 30 Jun 30 โ€“ Jul 21
Harvest October 6 Oct 6 โ€“ Nov 24

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 โ€”
June Direct Sow
July Transplant Outdoors Direct Sow
August โ€”
September โ€”
October Harvest
November Harvest
December โ€”

Growing Conditions

โ˜€๏ธ Sun

Full Sun (6-8+ hours)

๐Ÿ’ง Water

1"/week ยท Natural rainfall sufficient

๐Ÿ“… Days to Maturity

90โ€“120 days

๐Ÿงช Soil pH

Needs 6โ€“7.5 ยท Your soil: acceptable

๐Ÿ—บ๏ธ USDA Zone

Zone 4b

๐Ÿ“† Growing Season

83 days in Eagle County

Growing Tips for Amaranth in Eagle County

Direct sow Amaranth outdoors after June 16 in Eagle County when soil has warmed and frost danger has passed.

Your 83.0-day growing season in Eagle County is tight for Amaranth (90.0-120.0 days to maturity). Start indoors and choose early-maturing varieties.

Eagle County receives only 24" of rain annually. Amaranth needs consistent moisture โ€” install drip irrigation or water deeply 2-3 times per week.

General growing tips

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

  • Fennel

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Amaranth in Eagle County, CO?

Eagle County is in Zone 4b with an average last frost of June 16. Plan your Amaranth planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Eagle County, CO?

Eagle County, Colorado is in USDA Hardiness Zone 4b. The average last spring frost is June 16 and first fall frost is September 7.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Eagle County gardeners in Zone 4b organize planting dates, track what's growing, and never miss a planting window.

Get Your Free Garden Planner →

Free download. Plan your entire garden season in minutes.

Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for Eagle County, CO. Local conditions may vary. Last updated: April 2026.