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When to plant Amaranth in Bingham County, ID

Bingham County sits in cold Zone 5b. Plant Amaranth May 28–June 18 for the single annual harvest; the September 21 first frost closes the window.

When to Plant Amaranth in Bingham County, ID

Bingham County, Idaho Zone 5b July

Your July planting checklist for Bingham County, Idaho

Welcome to July in Zone 5b. These are the moves that will have the biggest impact on your growing season.

Avg. last frost May 21
Avg. first frost September 21
Soil temp (4") 52°F
Watering High
Pest pressure High
Daylight 14.9 hrs
  1. Begin indoor sowing: amaranth

    You're about 7 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.

Bingham County, Idaho is in USDA Zone 5b. The average last spring frost is May 21 and the first fall frost is September 21, giving you a growing season of approximately 123 days.

At an elevation of 8,345 feet, Bingham County receives approximately 24.5 inches of rainfall annually with predominantly loam soil. Summer highs average 86°F, providing good warmth for Amaranth during the growing season.

Bingham County, ID (Zone 5b) Short season
123 days
Last Spring Frost May 21
123 growing days
First Fall Frost September 21

Bingham County Soil Profile

Soil Type

Loam

Soil pH

6.3-7.7

Drainage

Well Drained

Amaranth Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Start indoors: Mar 15 Transplant: May 24 🍅 Harvest: Aug 23 – Oct 11
Recommended (50%) ✗ May not fit
Start indoors: Mar 26 Transplant: Jun 4 🍅 Harvest: Sep 3 – Oct 22
Safe Start (90%) ✗ May not fit
Start indoors: Apr 21 Transplant: Jun 30 🍅 Harvest: Sep 29 – Nov 17

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 Bingham County

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

Soil pH

Your soil pH (6.3–7.7) overlaps with Amaranth's range (6.0–7.5), though not a perfect match.

Soil Texture

The loam soil in Bingham 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

Amaranth Water Budget

Plant needs
1.0″/week
Rainfall provides
0.8″/week
You supply
0.2″/week
Watering frequency Only during dry spells
Season total 215 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 1.5" 0" ❄️ Dormant
Feb 1.4" 0" ❄️ Dormant
Mar 2.1" 0" ❄️ Dormant
Apr 2.9" 0" ❄️ Dormant
May 4.3" 2.5" 1.8" 💧 Light watering
Jun 4.3" 1.5" 2.8" 🚿 Regular watering
Jul 4.3" 2.3" 2" 💧 Light watering
Aug 4.3" 2.5" 1.8" 💧 Light watering
Sep 4.3" 2.3" 2" 💧 Light watering
Oct 2.4" 0" ❄️ Dormant
Nov 1.8" 0" ❄️ Dormant
Dec 1.2" 0" ❄️ Dormant

Water needs are for active growing months only (May–Sep in Bingham 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 1,783 GDD Good fit

Amaranth Planting Timeline — Bingham County, ID

Amaranth Planting Calendar

Activity When Date Range
Start Indoors March 26 Mar 26 – Apr 9
Transplant Outdoors June 4 Jun 4 – Jun 18
Direct Sow May 28 May 28 – Jun 18
Harvest September 3 Sep 3 – Oct 22

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

Month-by-Month Timeline

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

🗺️ USDA Zone

Zone 5b

📆 Growing Season

123 days in Bingham County

Growing Tips for Amaranth in Bingham County

Direct sow Amaranth outdoors after May 21 in Bingham County when soil has warmed and frost danger has passed.

Your 123.0-day growing season in Bingham County is tight for Amaranth (90.0-120.0 days to maturity). Start indoors and choose early-maturing varieties.

Bingham County receives only 24" 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 Bingham County, ID?

Bingham County is in Zone 5b with an average last frost of May 21. Plan your Amaranth planting based on this frost date — see the calendar above for exact timing.

What planting zone is Bingham County, ID?

Bingham County, Idaho is in USDA Hardiness Zone 5b. The average last spring frost is May 21 and first fall frost is September 21.

When should I plant Amaranth in Bingham County, ID?

In Bingham County, ID, plant Amaranth after the last frost (around May 21) and before the first frost (around September 21). Best results when soil holds above 50°F.

What growing zone is Bingham County, ID for Amaranth?

Bingham County sits in USDA Zone 5b. Amaranth grows reliably in zones 2a through 11b, so it's a good fit here.

Can Amaranth grow in Bingham County's climate?

Yes — Amaranth grows well in Bingham County's temperate climate. Bingham County averages a 123-day frost-free season, with last frost around May 21 and first frost around September 21.

🌱

Your Bingham County Garden Planner — Free

A 22-page printable planner built for Bingham County (Zone 5b). 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 Bingham County, ID. Local conditions may vary. Last updated: July 2026.

Sources & credits

Every number on this page traces back to a primary horticulture or government data source. Click through to verify.