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When to Plant Amaranth in Hardin County, IL

Hardin County, Illinois Zone 7a May

May to-do list for Hardin County, Illinois

May rewards gardeners who work with the weather, not against it. Here's how to stay in step this month in Hardin County, Illinois.

Avg. last frost April 4
Avg. first frost October 31
Soil temp (4") 61°F
Watering Moderate
Pest pressure Low
Daylight 14 hrs
  1. Time to start amaranth inside

    These need a head start before your last frost (April 4). Sow into cells now so you're ready to transplant in a few weeks.

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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.

Hardin County, Illinois is in USDA Zone 7a. The average last spring frost is April 4 and the first fall frost is October 31, giving you a growing season of approximately 210 days.

At an elevation of 1,218 feet, Hardin County receives approximately 30.2 inches of rainfall annually with predominantly silt loam soil. Summer highs average 88°F, providing good warmth for Amaranth during the growing season.

Hardin County, IL (Zone 7a) Long season
210 days
Last Spring Frost April 4
210 growing days
First Fall Frost October 31
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Hardin County Soil Profile

Soil Type

Silt Loam

Soil pH

6.2-7.2

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (54 days to spare)
Start indoors: Feb 7 Transplant: Apr 11 🍅 Harvest: Jul 11 – Aug 29
Recommended (50%) ✓ Fits season (56 days to spare)
Start indoors: Feb 14 Transplant: Apr 18 🍅 Harvest: Jul 18 – Sep 5
Safe Start (90%) ✓ Fits season (64 days to spare)
Start indoors: Feb 27 Transplant: May 1 🍅 Harvest: Jul 31 – Sep 18

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 Hardin County

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

Soil pH

Your soil pH (6.2–7.2) is within Amaranth's preferred range (6.0–7.5).

Soil Texture

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

Organic Matter

Organic matter is excellent (4.1%) — 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
0.6″/week
You supply
0.4″/week
Watering frequency 1-2 times/week
Season total 740 gal / 100 sq ft

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 1.4" 0" ❄️ Dormant
Feb 1.2" 0" ❄️ Dormant
Mar 2.3" 0" ❄️ Dormant
Apr 4.3" 3.2" 1.1" 💧 Light watering
May 4.3" 3.1" 1.2" 💧 Light watering
Jun 4.3" 3.4" 0.9" 💧 Light watering
Jul 4.3" 3" 1.3" 💧 Light watering
Aug 4.3" 3.4" 0.9" 💧 Light watering
Sep 4.3" 2.8" 1.5" 💧 Light watering
Oct 4.3" 2.7" 1.6" 💧 Light watering
Nov 2.1" 0" ❄️ Dormant
Dec 1.6" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Hardin 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 ~1,680 GDD — county provides 3,360 GDD Excellent fit

Amaranth Planting Timeline — Hardin County, IL

Amaranth Planting Calendar

Activity When Date Range
Start Indoors February 14 Feb 14 – Feb 28
Transplant Outdoors April 18 Apr 18 – May 2
Direct Sow April 11 Apr 11 – May 2
Harvest July 18 Jul 18 – Sep 5

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

Month-by-Month Timeline

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

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1"/week · 1-2 times/week

📅 Days to Maturity

90–120 days

🧪 Soil pH

Needs 6–7.5 · Your soil: ideal

🗺️ USDA Zone

Zone 7a

📆 Growing Season

210 days in Hardin County

Growing Tips for Amaranth in Hardin County

Direct sow Amaranth outdoors after April 04 in Hardin 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 Hardin County, IL?

Hardin County is in Zone 7a with an average last frost of April 4. Plan your Amaranth planting based on this frost date — see the calendar above for exact timing.

What planting zone is Hardin County, IL?

Hardin County, Illinois is in USDA Hardiness Zone 7a. The average last spring frost is April 4 and first fall frost is October 31.

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Your Hardin County Garden Planner — Free

A 24-page printable planner built for Hardin County (Zone 7a). 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 Hardin County, IL. Local conditions may vary. Last updated: May 2026.

Sources & credits

Every number on this page traces back to a primary horticulture or government data source. Click through to verify.