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When to Plant Amaranth in Shelby County, MO

Shelby County, Missouri Zone 6a May

Your May gardening checklist

May is a pivotal month for Shelby County, Missouri gardens. Focus on these tasks first and you'll set up the rest of the season for success.

Avg. last frost April 17
Avg. first frost October 17
Soil temp (4") 59°F
Watering Low
Pest pressure Low
Daylight 14.2 hrs
  1. Time to transplant amaranth

    Your last frost (April 17) has passed. These warm-season crops can handle outdoor soil now.

June will be here before you know it — start on
  • Starting indoors: amaranth

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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.

Shelby County, Missouri is in USDA Zone 6a. The average last spring frost is April 17 and the first fall frost is October 17, giving you a growing season of approximately 183 days.

At an elevation of 1,216 feet, Shelby County receives approximately 40.6 inches of rainfall annually with predominantly silt loam soil. Summer highs average 84°F, so choose short-season varieties of Amaranth to ensure they mature before fall.

Shelby County, MO (Zone 6a) Moderate season
183 days
Last Spring Frost April 17
183 growing days
First Fall Frost October 17
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Shelby County Soil Profile

Soil Type

Silt Loam

Soil pH

5.7-6.8

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (28 days to spare)
Start indoors: Feb 15 Transplant: Apr 26 🍅 Harvest: Jul 26 – Sep 13
Recommended (50%) ✓ Fits season (29 days to spare)
Start indoors: Feb 20 Transplant: May 1 🍅 Harvest: Jul 31 – Sep 18
Safe Start (90%) ✓ Fits season (30 days to spare)
Start indoors: Mar 5 Transplant: May 14 🍅 Harvest: Aug 13 – Oct 1

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 Shelby County

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

Soil pH

Your soil pH (5.7–6.8) overlaps with Amaranth's range (6.0–7.5), though not a perfect match.

Soil Texture

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

Organic Matter

Organic matter is moderate (3.0%). 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 111 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 1.8" 0" ❄️ Dormant
Feb 1.7" 0" ❄️ Dormant
Mar 2.7" 0" ❄️ Dormant
Apr 4.3" 4" 0.3" 💧 Light watering
May 4.3" 5.1" 0" ✅ Rainfall sufficient
Jun 4.3" 4.9" 0" ✅ Rainfall sufficient
Jul 4.3" 4.8" 0" ✅ Rainfall sufficient
Aug 4.3" 4.2" 0.1" 💧 Light watering
Sep 4.3" 3.4" 0.9" 💧 Light watering
Oct 4.3" 3.2" 1.1" 💧 Light watering
Nov 2.6" 0" ❄️ Dormant
Dec 2.2" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Shelby 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 ~1,365 GDD — county provides 2,379 GDD Excellent fit

Amaranth Planting Timeline — Shelby County, MO

Amaranth Planting Calendar

Activity When Date Range
Start Indoors February 20 Feb 20 – Mar 6
Transplant Outdoors May 1 May 1 – May 15
Direct Sow April 24 Apr 24 – May 15
Harvest July 31 Jul 31 – Sep 18

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 Harvest
August Harvest
September Harvest
October
November
December
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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

183 days in Shelby County

Growing Tips for Amaranth in Shelby County

Direct sow Amaranth outdoors after April 17 in Shelby 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 Shelby County, MO?

Shelby County is in Zone 6a with an average last frost of April 17. Plan your Amaranth planting based on this frost date — see the calendar above for exact timing.

What planting zone is Shelby County, MO?

Shelby County, Missouri is in USDA Hardiness Zone 6a. The average last spring frost is April 17 and first fall frost is October 17.

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Your Shelby County Garden Planner — Free

A 24-page printable planner built for Shelby 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 Shelby County, MO. 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.