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When to Plant Amaranth in Benewah County, ID

Benewah County, Idaho Zone 6b May

Top priorities for Benewah County, Idaho gardeners in May

Each item below is timed to Benewah County, Idaho's frost dates and soil temperatures. Skip nothing, stress about nothing.

Avg. last frost May 8
Avg. first frost October 1
Soil temp (4") 44°F
Watering High
Pest pressure Low
Daylight 14.9 hrs
  1. Time to transplant amaranth

    Plant tomatoes deep — bury the stem up to the first true leaves to grow extra roots. Everything else goes in at the same depth it grew in the tray.

  2. Seed amaranth outdoors

    Thin ruthlessly once seedlings are up. Crowded roots mean smaller crops from every plant.

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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.

Benewah County, Idaho is in USDA Zone 6b. The average last spring frost is May 8 and the first fall frost is October 1, giving you a growing season of approximately 146 days.

At an elevation of 6,081 feet, Benewah County receives approximately 20.8 inches of rainfall annually with predominantly loam soil. Summer highs average 90°F, providing good warmth for Amaranth during the growing season.

Benewah County, ID (Zone 6b) Short season
146 days
Last Spring Frost May 8
146 growing days
First Fall Frost October 1
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Benewah County Soil Profile

Soil Type

Loam

Soil pH

6.3-7.8

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Start indoors: Mar 4 Transplant: May 13 🍅 Harvest: Aug 12 – Sep 30
Recommended (50%) ✗ May not fit
Start indoors: Mar 13 Transplant: May 22 🍅 Harvest: Aug 21 – Oct 9
Safe Start (90%) ✗ May not fit
Start indoors: Apr 11 Transplant: Jun 20 🍅 Harvest: Sep 19 – Nov 7

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 Benewah County

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

Soil pH

Your soil pH (6.3–7.8) overlaps with Amaranth's range (6.0–7.5), though not a perfect match.

Soil Texture

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

Organic Matter

Organic matter is moderate (2.2%). 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
0.6″/week
You supply
0.5″/week
Watering frequency 1-2 times/week
Season total 626 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 1.4" 0" ❄️ Dormant
Feb 1.3" 0" ❄️ Dormant
Mar 2" 0" ❄️ Dormant
Apr 2.1" 0" ❄️ Dormant
May 4.3" 2.5" 1.8" 💧 Light watering
Jun 4.3" 1.5" 2.8" 🚿 Regular watering
Jul 4.3" 1.7" 2.6" 🚿 Regular watering
Aug 4.3" 2.2" 2.1" 💧 Light watering
Sep 4.3" 1.6" 2.7" 🚿 Regular watering
Oct 4.3" 1.8" 2.5" 🚿 Regular watering
Nov 1.6" 0" ❄️ Dormant
Dec 1.3" 0" ❄️ Dormant

Water needs are for active growing months only (May–Oct in Benewah 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 ~1,838 GDD — county provides 2,555 GDD Excellent fit

Amaranth Planting Timeline — Benewah County, ID

Amaranth Planting Calendar

Activity When Date Range
Start Indoors March 13 Mar 13 – Mar 27
Transplant Outdoors May 22 May 22 – Jun 5
Direct Sow May 15 May 15 – Jun 5
Harvest August 21 Aug 21 – Oct 9

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

Month-by-Month Timeline

MonthActivities
January
February
March Start Indoors
April
May Transplant Outdoors Direct Sow
June Transplant Outdoors Direct Sow
July
August Harvest
September Harvest
October Harvest
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: acceptable

🗺️ USDA Zone

Zone 6b

📆 Growing Season

146 days in Benewah County

Growing Tips for Amaranth in Benewah County

Direct sow Amaranth outdoors after May 08 in Benewah County when soil has warmed and frost danger has passed.

Benewah County receives only 21" of rain annually. Amaranth needs consistent moisture — install drip irrigation or water deeply 2-3 times per week.

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 Benewah County, ID?

Benewah County is in Zone 6b with an average last frost of May 8. Plan your Amaranth planting based on this frost date — see the calendar above for exact timing.

What planting zone is Benewah County, ID?

Benewah County, Idaho is in USDA Hardiness Zone 6b. The average last spring frost is May 8 and first fall frost is October 1.

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Your Benewah County Garden Planner — Free

A 24-page printable planner built for Benewah 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 Benewah County, ID. 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.