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When to plant Amaranth in Johnson County, MO

For Amaranth in Johnson County, the safe spring window opens around April 20 and closes around May 11. Last expected frost is April 13, first fall frost October 23, giving a 193-day growing season.

When to Plant Amaranth in Johnson County, MO

Johnson County, Missouri Zone 6b June

This month in Johnson County, Missouri

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

Avg. last frost April 13
Avg. first frost October 23
Soil temp (4") 75°F
Watering Low
Pest pressure High
Daylight 14.7 hrs
  1. Begin indoor sowing: amaranth

    Give them 6–8 weeks indoors before the last frost and you'll transplant into warm soil with seedlings that are already leaping.

To set up a strong July, finish these tasks
  • First harvests: 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.

Johnson County, Missouri is in USDA Zone 6b. The average last spring frost is April 13 and the first fall frost is October 23, giving you a growing season of approximately 193 days.

At an elevation of 1,218 feet, Johnson County receives approximately 41 inches of rainfall annually with predominantly silt loam soil. Summer highs average 86°F, providing good warmth for Amaranth during the growing season.

Johnson County, MO (Zone 6b) Moderate season
193 days
Last Spring Frost April 13
193 growing days
First Fall Frost October 23

Johnson County Soil Profile

Soil Type

Silt Loam

Soil pH

5.3-6.5

Drainage

Well Drained

Amaranth Planting Risk Windows

Early Start (70% safe) ✓ Fits season (40 days to spare)
Start indoors: Feb 8 Transplant: Apr 19 🍅 Harvest: Jul 19 – Sep 6
Recommended (50%) ✓ Fits season (39 days to spare)
Start indoors: Feb 16 Transplant: Apr 27 🍅 Harvest: Jul 27 – Sep 14
Safe Start (90%) ✓ Fits season (40 days to spare)
Start indoors: Feb 28 Transplant: May 9 🍅 Harvest: Aug 8 – Sep 26

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 Johnson 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 silt loam soil in Johnson 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

Amaranth 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 185 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 1.5" 0" ❄️ Dormant
Feb 1.9" 0" ❄️ Dormant
Mar 2.5" 0" ❄️ Dormant
Apr 4.3" 3.6" 0.7" 💧 Light watering
May 4.3" 4.5" 0" ✅ Rainfall sufficient
Jun 4.3" 5.8" 0" ✅ Rainfall sufficient
Jul 4.3" 4.1" 0.2" 💧 Light watering
Aug 4.3" 4.9" 0" ✅ Rainfall sufficient
Sep 4.3" 3.8" 0.5" 💧 Light watering
Oct 4.3" 3" 1.3" 💧 Light watering
Nov 2.8" 0" ❄️ Dormant
Dec 2.6" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Johnson 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 ~1,522 GDD — county provides 2,798 GDD Excellent fit

Amaranth Planting Timeline — Johnson County, MO

Amaranth Planting Calendar

Activity When Date Range
Start Indoors February 16 Feb 16 – Mar 2
Transplant Outdoors April 27 Apr 27 – May 11
Direct Sow April 20 Apr 20 – May 11
Harvest July 27 Jul 27 – Sep 14

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 6b

📆 Growing Season

193 days in Johnson County

Growing Tips for Amaranth in Johnson County

Direct sow Amaranth outdoors after April 13 in Johnson 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 Johnson County, MO?

Johnson County is in Zone 6b with an average last frost of April 13. Plan your Amaranth planting based on this frost date — see the calendar above for exact timing.

What planting zone is Johnson County, MO?

Johnson County, Missouri is in USDA Hardiness Zone 6b. The average last spring frost is April 13 and first fall frost is October 23.

When should I plant Amaranth in Johnson County, MO?

In Johnson County, MO, plant Amaranth after the last frost (around April 13) and before the first frost (around October 23). Best results when soil holds above 50°F.

What growing zone is Johnson County, MO for Amaranth?

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

Can Amaranth grow in Johnson County's climate?

Yes — Amaranth grows well in Johnson County's temperate climate. Johnson County averages a 193-day frost-free season, with last frost around April 13 and first frost around October 23.

🌱

Your Johnson County Garden Planner — Free

A 22-page printable planner built for Johnson County (Zone 6b). 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 Johnson County, MO. Local conditions may vary. Last updated: June 2026.

Sources & credits

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