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When to Plant Amaranth in Chaffee 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.

Chaffee County, Colorado is in USDA Zone 5a. 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 7,788 feet, Chaffee County receives approximately 18.6 inches of rainfall annually with predominantly loam soil. Summer highs average 86ยฐF, providing good warmth for Amaranth during the growing season. With low rainfall, drip irrigation is essential for growing Amaranth successfully. Mulch heavily to conserve soil moisture.

Chaffee County, CO (Zone 5a) Very short season
83 days
Last Spring Frost June 16
83 growing days
First Fall Frost September 7

Chaffee County Soil Profile

Soil Type

Loam

Soil pH

6.7-7.6

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Start indoors: Apr 15 Transplant: Jun 24 🍅 Harvest: Sep 23 – Nov 11
Recommended (50%) ✗ May not fit
Start indoors: Apr 21 Transplant: Jun 30 🍅 Harvest: Sep 29 – Nov 17
Safe Start (90%) ✗ May not fit
Start indoors: May 1 Transplant: Jul 10 🍅 Harvest: Oct 9 – Nov 27

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 Chaffee County

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

Soil pH

Your soil pH (6.7โ€“7.6) overlaps with Amaranth's range (6.0โ€“7.5), though not a perfect match.

Soil Texture

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

Organic Matter

Organic matter is moderate (2.6%). 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
0.9″/week
You supply
0.1″/week
Watering frequency Only during dry spells
Season total 52 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€” 1.4" 0" โ„๏ธ Dormant
Feb โ€” 1.2" 0" โ„๏ธ Dormant
Mar โ€” 1.4" 0" โ„๏ธ Dormant
Apr โ€” 1.8" 0" โ„๏ธ Dormant
May โ€” 2.4" 0" โ„๏ธ Dormant
Jun 4.3" 1.4" 2.9" ๐Ÿšฟ Regular watering
Jul 4.3" 1.8" 2.5" ๐Ÿšฟ Regular watering
Aug 4.3" 1.9" 2.4" ๐Ÿšฟ Regular watering
Sep 4.3" 1.4" 2.9" ๐Ÿšฟ Regular watering
Oct โ€” 1.5" 0" โ„๏ธ Dormant
Nov โ€” 1.3" 0" โ„๏ธ Dormant
Dec โ€” 1.1" 0" โ„๏ธ Dormant

Water needs are for active growing months only (Junโ€“Sep in Chaffee 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 ~1,522 GDD — county provides 1,203 GDD May not mature

Amaranth Planting Timeline โ€” Chaffee County, CO

Amaranth Planting Calendar

Activity When Date Range
Start Indoors April 21 Apr 21 โ€“ May 5
Transplant Outdoors June 30 Jun 30 โ€“ Jul 14
Direct Sow June 23 Jun 23 โ€“ Jul 14
Harvest September 29 Sep 29 โ€“ Nov 17

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

Growing Conditions

โ˜€๏ธ Sun

Full Sun (6-8+ hours)

๐Ÿ’ง Water

1"/week ยท Only during dry spells

๐Ÿ“… Days to Maturity

90โ€“120 days

๐Ÿงช Soil pH

Needs 6โ€“7.5 ยท Your soil: acceptable

๐Ÿ—บ๏ธ USDA Zone

Zone 5a

๐Ÿ“† Growing Season

83 days in Chaffee County

Growing Tips for Amaranth in Chaffee County

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

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

Chaffee County receives only 19" 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 Chaffee County, CO?

Chaffee County is in Zone 5a 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 Chaffee County, CO?

Chaffee County, Colorado is in USDA Hardiness Zone 5a. 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 Chaffee 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 Chaffee County, CO. Local conditions may vary. Last updated: April 2026.