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When to Plant Amaranth in Jefferson County, KY

Jefferson County, Kentucky Zone 7a May

May in the garden — Jefferson County, Kentucky

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

Avg. last frost April 7
Avg. first frost October 30
Soil temp (4") 56°F
Watering Moderate
Pest pressure Low
Daylight 14.1 hrs
  1. Begin indoor sowing: amaranth

    You're about 25 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.

Jefferson County, Kentucky is in USDA Zone 7a. The average last spring frost is April 7 and the first fall frost is October 30, giving you a growing season of approximately 206 days.

At an elevation of 3,279 feet, Jefferson County receives approximately 43.1 inches of rainfall annually with predominantly silt loam soil. Summer highs average 85°F, providing good warmth for Amaranth during the growing season.

Jefferson County, KY (Zone 7a) Long season
206 days
Last Spring Frost April 7
206 growing days
First Fall Frost October 30

Jefferson County Soil Profile

Soil Type

Silt Loam

Soil pH

5.2-6.6

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (54 days to spare)
Start indoors: Feb 8 Transplant: Apr 12 🍅 Harvest: Jul 12 – Aug 30
Recommended (50%) ✓ Fits season (52 days to spare)
Start indoors: Feb 17 Transplant: Apr 21 🍅 Harvest: Jul 21 – Sep 8
Safe Start (90%) ✓ Fits season (46 days to spare)
Start indoors: Mar 6 Transplant: May 8 🍅 Harvest: Aug 7 – Sep 25

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 Jefferson County

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

Soil pH

Your soil pH (5.2–6.6) is more acidic than Amaranth prefers (6.0–7.5). Add garden lime to raise pH.

Soil Texture

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

Organic Matter

Organic matter is moderate (2.6%). 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 222 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 3.2" 0" ❄️ Dormant
Feb 3.2" 0" ❄️ Dormant
Mar 4.5" 0" ❄️ Dormant
Apr 4.3" 2.9" 1.4" 💧 Light watering
May 4.3" 3.6" 0.7" 💧 Light watering
Jun 4.3" 4.1" 0.2" 💧 Light watering
Jul 4.3" 3.9" 0.4" 💧 Light watering
Aug 4.3" 4.5" 0" ✅ Rainfall sufficient
Sep 4.3" 3.7" 0.6" 💧 Light watering
Oct 4.3" 2.5" 1.8" 💧 Light watering
Nov 3.2" 0" ❄️ Dormant
Dec 3.8" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Jefferson 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 ~1,444 GDD — county provides 2,832 GDD Excellent fit

Amaranth Planting Timeline — Jefferson County, KY

Amaranth Planting Calendar

Activity When Date Range
Start Indoors February 17 Feb 17 – Mar 3
Transplant Outdoors April 21 Apr 21 – May 5
Direct Sow April 14 Apr 14 – May 5
Harvest July 21 Jul 21 – Sep 8

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

Month-by-Month Timeline

MonthActivities
January
February Start Indoors
March Start Indoors
April Transplant Outdoors Direct Sow
May Transplant Outdoors Direct Sow
June
July Harvest
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: too_acidic

🗺️ USDA Zone

Zone 7a

📆 Growing Season

206 days in Jefferson County

Growing Tips for Amaranth in Jefferson County

Direct sow Amaranth outdoors after April 07 in Jefferson 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 Jefferson County, KY?

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

What planting zone is Jefferson County, KY?

Jefferson County, Kentucky is in USDA Hardiness Zone 7a. The average last spring frost is April 7 and first fall frost is October 30.

🌱

Your Jefferson County Garden Planner — Free

A 24-page printable planner built for Jefferson 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 Jefferson County, KY. 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.