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When to Plant Amaranth in Salt Lake County, UT

Salt Lake County, Utah Zone 7b May

Your May planting checklist for Salt Lake County, Utah

Your Salt Lake County, Utah garden is entering a new phase. Here's what's on the schedule for May and why each task matters now.

Avg. last frost May 6
Avg. first frost October 10
Soil temp (4") 49°F
Watering High
Pest pressure Low
Daylight 14.3 hrs
  1. Transplant amaranth outside

    Your last frost (May 6) has passed. These warm-season crops can handle outdoor soil now.

  2. Outdoor sowing time: amaranth

    Sow every 2 weeks for a continuous harvest. A single big planting means a single big glut.

Looking ahead to June
  • Starting indoors: 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.

Salt Lake County, Utah is in USDA Zone 7b. The average last spring frost is May 6 and the first fall frost is October 10, giving you a growing season of approximately 157 days.

At an elevation of 4,960 feet, Salt Lake County receives approximately 12.2 inches of rainfall annually with predominantly loam soil. Summer highs average 88°F, providing good warmth for Amaranth during the growing season. With low rainfall, drip irrigation is essential for growing Amaranth successfully. Mulch heavily to conserve soil moisture.

Salt Lake County, UT (Zone 7b) Moderate season
157 days
Last Spring Frost May 6
157 growing days
First Fall Frost October 10
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Salt Lake County Soil Profile

Soil Type

Loam

Soil pH

6.7-8.3

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (2 days to spare)
Start indoors: Mar 8 Transplant: May 10 🍅 Harvest: Aug 9 – Sep 27
Recommended (50%) ✓ Fits season (3 days to spare)
Start indoors: Mar 18 Transplant: May 20 🍅 Harvest: Aug 19 – Oct 7
Safe Start (90%) ✗ May not fit
Start indoors: Apr 22 Transplant: Jun 24 🍅 Harvest: Sep 23 – Nov 11

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 Salt Lake County

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

Soil pH

Your soil pH (6.7–8.3) overlaps with Amaranth's range (6.0–7.5), though not a perfect match.

Soil Texture

The loam soil in Salt Lake 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
0.3″/week
You supply
0.8″/week
Watering frequency 2-3 times/week
Season total 1,130 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 0.9" 0" ❄️ Dormant
Feb 0.6" 0" ❄️ Dormant
Mar 1.1" 0" ❄️ Dormant
Apr 1.2" 0" ❄️ Dormant
May 4.3" 1.4" 2.9" 🚿 Regular watering
Jun 4.3" 1" 3.3" 🚿 Regular watering
Jul 4.3" 1.1" 3.2" 🚿 Regular watering
Aug 4.3" 1.4" 2.9" 🚿 Regular watering
Sep 4.3" 0.9" 3.4" 🚿 Regular watering
Oct 4.3" 1.2" 3.1" 🚿 Regular watering
Nov 0.8" 0" ❄️ Dormant
Dec 0.7" 0" ❄️ Dormant

Water needs are for active growing months only (May–Oct in Salt Lake 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 ~1,680 GDD — county provides 2,512 GDD Excellent fit

Amaranth Planting Timeline — Salt Lake County, UT

Amaranth Planting Calendar

Activity When Date Range
Start Indoors March 18 Mar 18 – Apr 1
Transplant Outdoors May 20 May 20 – Jun 3
Direct Sow May 13 May 13 – Jun 3
Harvest August 19 Aug 19 – Oct 7

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

Month-by-Month Timeline

MonthActivities
January
February
March Start Indoors
April Start Indoors
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 · 2-3 times/week

📅 Days to Maturity

90–120 days

🧪 Soil pH

Needs 6–7.5 · Your soil: acceptable

🗺️ USDA Zone

Zone 7b

📆 Growing Season

157 days in Salt Lake County

Growing Tips for Amaranth in Salt Lake County

Direct sow Amaranth outdoors after May 06 in Salt Lake County when soil has warmed and frost danger has passed.

Salt Lake County receives only 12" 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 Salt Lake County, UT?

Salt Lake County is in Zone 7b with an average last frost of May 6. Plan your Amaranth planting based on this frost date — see the calendar above for exact timing.

What planting zone is Salt Lake County, UT?

Salt Lake County, Utah is in USDA Hardiness Zone 7b. The average last spring frost is May 6 and first fall frost is October 10.

🌱

Your Salt Lake County Garden Planner — Free

A 24-page printable planner built for Salt Lake County (Zone 7b). 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 Salt Lake County, UT. 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.