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When to Plant Amaranth in Cobb County, GA

Cobb County, Georgia Zone 8a May

May in Cobb County, Georgia — your action list

Welcome to May in Zone 8a. These are the moves that will have the biggest impact on your growing season.

Avg. last frost March 31
Avg. first frost November 1
Soil temp (4") 67°F
Watering Low
Pest pressure Moderate
Daylight 13.8 hrs
  1. Get amaranth seeds going inside

    Starting these indoors now means sturdy transplants ready the moment your soil warms up.

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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.

Cobb County, Georgia is in USDA Zone 8a. The average last spring frost is March 31 and the first fall frost is November 1, giving you a growing season of approximately 215 days.

At an elevation of 387 feet, Cobb County receives approximately 57.2 inches of rainfall annually with predominantly clay loam soil. Summer highs average 89°F, providing good warmth for Amaranth during the growing season. Clay soil retains moisture well for Amaranth, but amend with compost to improve drainage and prevent root rot. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Amaranth root diseases.

Cobb County, GA (Zone 8a) Long season
215 days
Last Spring Frost March 31
215 growing days
First Fall Frost November 1
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Cobb County Soil Profile

Soil Type

Clay Loam

Soil pH

5.3-6.5

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (63 days to spare)
Start indoors: Feb 2 Transplant: Apr 6 🍅 Harvest: Jul 6 – Aug 24
Recommended (50%) ✓ Fits season (61 days to spare)
Start indoors: Feb 10 Transplant: Apr 14 🍅 Harvest: Jul 14 – Sep 1
Safe Start (90%) ✓ Fits season (66 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 Cobb County

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

Soil pH

Your soil pH (5.3–6.5) is more acidic than Amaranth prefers (6.0–7.5). Add garden lime to raise pH.

Soil Texture

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

Drainage

Drainage is adequate for Amaranth.

Organic Matter

Organic matter is moderate (2.3%). 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
1.1″/week
Watering frequency Natural rainfall sufficient
Season total 0 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 4.2" 0" ❄️ Dormant
Feb 4" 0" ❄️ Dormant
Mar 4.3" 6" 0" ✅ Rainfall sufficient
Apr 4.3" 4.7" 0" ✅ Rainfall sufficient
May 4.3" 3.9" 0.4" 💧 Light watering
Jun 4.3" 5.8" 0" ✅ Rainfall sufficient
Jul 4.3" 5.5" 0" ✅ Rainfall sufficient
Aug 4.3" 5.2" 0" ✅ Rainfall sufficient
Sep 4.3" 4.7" 0" ✅ Rainfall sufficient
Oct 4.3" 3.7" 0.6" 💧 Light watering
Nov 4.3" 4.3" 0" ✅ Rainfall sufficient
Dec 5.2" 0" ❄️ Dormant

Water needs are for active growing months only (Mar–Nov in Cobb 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 ~1,759 GDD — county provides 3,601 GDD Excellent fit

Amaranth Planting Timeline — Cobb County, GA

Amaranth Planting Calendar

Activity When Date Range
Start Indoors February 10 Feb 10 – Feb 24
Transplant Outdoors April 14 Apr 14 – Apr 28
Direct Sow April 7 Apr 7 – Apr 28
Harvest July 14 Jul 14 – Sep 1

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

Month-by-Month Timeline

MonthActivities
January
February Start Indoors
March
April Transplant Outdoors Direct Sow
May
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 · Natural rainfall sufficient

📅 Days to Maturity

90–120 days

🧪 Soil pH

Needs 6–7.5 · Your soil: too_acidic

🗺️ USDA Zone

Zone 8a

📆 Growing Season

215 days in Cobb County

Growing Tips for Amaranth in Cobb County

Direct sow Amaranth outdoors after March 31 in Cobb County when soil has warmed and frost danger has passed.

With Cobb County's clay soil (26% clay), work in 3-4 inches of compost before planting Amaranth. Avoid tilling when soil is wet to prevent compaction.

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 Cobb County, GA?

Cobb County is in Zone 8a with an average last frost of March 31. Plan your Amaranth planting based on this frost date — see the calendar above for exact timing.

What planting zone is Cobb County, GA?

Cobb County, Georgia is in USDA Hardiness Zone 8a. The average last spring frost is March 31 and first fall frost is November 1.

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Your Cobb County Garden Planner — Free

A 24-page printable planner built for Cobb County (Zone 8a). 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 Cobb County, GA. 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.