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When to Plant Amaranth in Door County, WI

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.

Door County, Wisconsin is in USDA Zone 5a. The average last spring frost is May 11 and the first fall frost is October 8, giving you a growing season of approximately 150 days.

At an elevation of 564 feet, Door County receives approximately 41.8 inches of rainfall annually with predominantly silt loam soil. Summer highs average 87ยฐF, providing good warmth for Amaranth during the growing season.

Door County, WI (Zone 5a) Moderate season
150 days
Last Spring Frost May 11
150 growing days
First Fall Frost October 8

Door County Soil Profile

Soil Type

Silt Loam

Soil pH

6-7.3

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Start indoors: Mar 10 Transplant: May 19 🍅 Harvest: Aug 18 – Oct 6
Recommended (50%) ✗ May not fit
Start indoors: Mar 16 Transplant: May 25 🍅 Harvest: Aug 24 – Oct 12
Safe Start (90%) ✗ May not fit
Start indoors: Mar 31 Transplant: Jun 9 🍅 Harvest: Sep 8 – Oct 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 Door County

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

Soil pH

Your soil pH (6.0โ€“7.3) is within Amaranth's preferred range (6.0โ€“7.5).

Soil Texture

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

Drainage

Drainage is adequate for Amaranth.

Organic Matter

Organic matter is excellent (4.7%) โ€” Amaranth will thrive.

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
You supply
0.2″/week
Watering frequency Only during dry spells
Season total 208 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€” 1.7" 0" โ„๏ธ Dormant
Feb โ€” 1.7" 0" โ„๏ธ Dormant
Mar โ€” 2.8" 0" โ„๏ธ Dormant
Apr โ€” 3.4" 0" โ„๏ธ Dormant
May 4.3" 4.6" 0" โœ… Rainfall sufficient
Jun 4.3" 5.7" 0" โœ… Rainfall sufficient
Jul 4.3" 4.7" 0" โœ… Rainfall sufficient
Aug 4.3" 4.4" 0" โœ… Rainfall sufficient
Sep 4.3" 3.7" 0.6" ๐Ÿ’ง Light watering
Oct 4.3" 3.6" 0.7" ๐Ÿ’ง Light watering
Nov โ€” 3.2" 0" โ„๏ธ Dormant
Dec โ€” 2.3" 0" โ„๏ธ Dormant

Water needs are for active growing months only (Mayโ€“Oct in Door 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 ~1,601 GDD — county provides 2,287 GDD Excellent fit

Amaranth Planting Timeline โ€” Door County, WI

Amaranth Planting Calendar

Activity When Date Range
Start Indoors March 16 Mar 16 โ€“ Mar 30
Transplant Outdoors May 25 May 25 โ€“ Jun 8
Direct Sow May 18 May 18 โ€“ Jun 8
Harvest August 24 Aug 24 โ€“ Oct 12

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

Month-by-Month Timeline

MonthActivities
January โ€”
February โ€”
March Start Indoors
April โ€”
May Transplant Outdoors Direct Sow
June Transplant Outdoors Direct Sow
July โ€”
August Harvest
September Harvest
October Harvest
November โ€”
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: ideal

๐Ÿ—บ๏ธ USDA Zone

Zone 5a

๐Ÿ“† Growing Season

150 days in Door County

Growing Tips for Amaranth in Door County

Direct sow Amaranth outdoors after May 11 in Door County when soil has warmed and frost danger has passed.

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 Door County, WI?

Door County is in Zone 5a with an average last frost of May 11. Plan your Amaranth planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Door County, WI?

Door County, Wisconsin is in USDA Hardiness Zone 5a. The average last spring frost is May 11 and first fall frost is October 8.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Door County gardeners in Zone 5a 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 Door County, WI. Local conditions may vary. Last updated: April 2026.