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When to plant Amaranth in Plainfield, IL

Plant Amaranth in Plainfield from April 30 to May 21 in spring. Plainfield sits in USDA Zone 6a, with last frost around April 23 and first frost on October 17.

When to Plant Amaranth in Plainfield, IL

Will County, Illinois Zone 6a June

This month in Will County, Illinois

Your Will County, Illinois garden is entering a new phase. Here's what's on the schedule for June and why each task matters now.

Avg. last frost April 23
Avg. first frost October 17
Soil temp (4") 69°F
Watering Low
Pest pressure High
Daylight 15 hrs
  1. Get amaranth seeds going inside

    You're about 17 weeks out from your last frost — the perfect window to get these germinating indoors.

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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.

Plainfield, Illinois is in USDA Zone 6a. The average last spring frost is April 23 and the first fall frost is October 17, giving you a growing season of approximately 177 days.

At an elevation of 655 feet, Will County receives approximately 41.8 inches of rainfall annually with predominantly silt loam soil. Summer highs average 83°F, so choose short-season varieties of Amaranth to ensure they mature before fall.

Plainfield, IL (Zone 6a) Moderate season
177 days
Last Spring Frost April 23
177 growing days
First Fall Frost October 17

Plainfield Soil Profile

Soil Type

Silt Loam

Soil pH

5.7-7.2

Drainage

Well Drained

Amaranth Planting Risk Windows

Early Start (70% safe) ✓ Fits season (22 days to spare)
Start indoors: Feb 21 Transplant: May 2 🍅 Harvest: Aug 1 – Sep 19
Recommended (50%) ✓ Fits season (23 days to spare)
Start indoors: Feb 26 Transplant: May 7 🍅 Harvest: Aug 6 – Sep 24
Safe Start (90%) ✓ Fits season (20 days to spare)
Start indoors: Mar 15 Transplant: May 24 🍅 Harvest: Aug 23 – Oct 11

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 Plainfield

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

Soil pH

Your soil pH (5.7–7.2) overlaps with Amaranth's range (6.0–7.5), though not a perfect match.

Soil Texture

The silt loam soil in Will County is excellent for Amaranth — good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is excellent (5.0%) — Amaranth will thrive.

How to Plant Amaranth

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

Amaranth Water Budget

Plant needs
1.0″/week
Rainfall provides
1.0″/week
You supply
0.0″/week
Watering frequency Only during dry spells
Season total 15 gal / 100 sq ft
Drought risk

Water stress score is 6/10 — 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 1.6" 0" ❄️ Dormant
Feb 1.8" 0" ❄️ Dormant
Mar 2.9" 0" ❄️ Dormant
Apr 4.3" 4.2" 0.1" 💧 Light watering
May 4.3" 4.4" 0" ✅ Rainfall sufficient
Jun 4.3" 5.3" 0" ✅ Rainfall sufficient
Jul 4.3" 4.5" 0" ✅ Rainfall sufficient
Aug 4.3" 4.4" 0" ✅ Rainfall sufficient
Sep 4.3" 3.4" 0.9" 💧 Light watering
Oct 4.3" 3.4" 0.9" 💧 Light watering
Nov 3.3" 0" ❄️ Dormant
Dec 2.7" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Will County). Supplement amounts are based on average rainfall — 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" — every day above 50°F 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 ~1,286 GDD — county provides 2,168 GDD Excellent fit

Amaranth Planting Timeline — Plainfield, IL

Amaranth Planting Calendar

Activity When Date Range
Start Indoors February 26 Feb 26 – Mar 12
Transplant Outdoors May 7 May 7 – May 21
Direct Sow April 30 Apr 30 – May 21
Harvest August 6 Aug 6 – Sep 24

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

Month-by-Month Timeline

MonthActivities
January
February Start Indoors
March Start Indoors
April Direct Sow
May Transplant Outdoors Direct Sow
June
July
August Harvest
September Harvest
October
November
December

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1"/week · Only during dry spells

📅 Days to Maturity

90–120 days

🧪 Soil pH

Needs 6–7.5 · Your soil: acceptable

🗺️ USDA Zone

Zone 6a

📆 Growing Season

177 days in Will County

Growing Tips for Amaranth in Plainfield

Direct sow Amaranth outdoors after April 23 in Will 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 →

When should I plant Amaranth in Plainfield, IL?

In Plainfield, IL, plant Amaranth after the last frost (around April 23) and before the first frost (around October 17). Best results when soil holds above 50°F.

What growing zone is Plainfield, IL for Amaranth?

Plainfield sits in USDA Zone 6a. Amaranth grows reliably in zones 2a through 11b, so it's a good fit here.

Can Amaranth grow in Plainfield's climate?

Yes — Amaranth grows well in Plainfield's temperate climate. Plainfield averages a 177-day frost-free season, with last frost around April 23 and first frost around October 17.

🌱

Your Will County Garden Planner — Free

A 22-page printable planner built for Will County (Zone 6a). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.

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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 Will County, IL. Local conditions may vary. Last updated: June 2026.