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When to Plant Amaranth in Pinal County, AZ

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.

Pinal County, Arizona is in USDA Zone 9a. The average last spring frost is February 23 and the first fall frost is November 27, giving you a growing season of approximately 277 days.

At an elevation of 3,959 feet, Pinal County receives approximately 15.8 inches of rainfall annually with predominantly sandy loam soil. Summer highs average 98ยฐF, so Amaranth may need afternoon shade and extra watering during peak heat. Sandy soil warms quickly in spring โ€” great for early planting โ€” but Amaranth will need more frequent watering and organic matter to retain nutrients. With low rainfall, drip irrigation is essential for growing Amaranth successfully. Mulch heavily to conserve soil moisture.

Pinal County, AZ (Zone 9a) Year-round
277 days
Last Spring Frost February 23
277 growing days
First Fall Frost November 27

Pinal County Soil Profile

Soil Type

Sandy Loam

Soil pH

7-8.6

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (138 days to spare)
Start indoors: Dec 30 Transplant: Feb 17 🍅 Harvest: May 19 – Jul 7
Recommended (50%) ✓ Fits season (130 days to spare)
Start indoors: Jan 12 Transplant: Mar 2 🍅 Harvest: Jun 1 – Jul 20
Safe Start (90%) ✓ Fits season (118 days to spare)
Start indoors: Feb 10 Transplant: Mar 31 🍅 Harvest: Jun 30 – Aug 18

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 Pinal County

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

Soil pH

Your soil pH (7.0โ€“8.6) is more alkaline than Amaranth prefers (6.0โ€“7.5). Add sulfur or peat moss to lower pH.

Soil Texture

Sandy soil in Pinal County warms quickly in spring but drains fast. Amaranth will need more frequent watering and regular compost additions to retain nutrients.

Drainage

Drainage is adequate for Amaranth.

Organic Matter

Organic matter is low (0.7%). Add 2-3 inches of compost before planting Amaranth.

How to Plant Amaranth

1"
Planting Depth
15"
Between Plants
24"
Between Rows

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
0.2″/week
You supply
1.3″/week
Watering frequency 2-3 times/week
Season total 3,151 gal / 100 sq ft
Drought risk

Water stress score is 10/10 โ€” 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 โ€” 1" 0" โ„๏ธ Dormant
Feb 4.3" 1" 3.3" ๐Ÿšฟ Regular watering
Mar 4.3" 0.8" 3.5" ๐Ÿšฟ Regular watering
Apr 4.3" 0.5" 3.8" ๐Ÿšฟ Regular watering
May 4.3" 0.3" 4" ๐Ÿšฟ Regular watering
Jun 4.3" 0.5" 3.8" ๐Ÿšฟ Regular watering
Jul 4.3" 3" 1.3" ๐Ÿ’ง Light watering
Aug 4.3" 3.5" 0.8" ๐Ÿ’ง Light watering
Sep 4.3" 1.9" 2.4" ๐Ÿšฟ Regular watering
Oct 4.3" 1.5" 2.8" ๐Ÿšฟ Regular watering
Nov 4.3" 0.8" 3.5" ๐Ÿšฟ Regular watering
Dec โ€” 1" 0" โ„๏ธ Dormant

Water needs are for active growing months only (Febโ€“Nov in Pinal County). Supplement amounts are based on average rainfall โ€” 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" โ€” every day above 50ยฐF 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 ~2,468 GDD — county provides 6,533 GDD Excellent fit

Amaranth Planting Timeline โ€” Pinal County, AZ

Amaranth Planting Calendar

Activity When Date Range
Start Indoors January 12 Jan 12 โ€“ Jan 26
Transplant Outdoors March 2 Mar 2 โ€“ Mar 16
Direct Sow February 23 Feb 23 โ€“ Mar 16
Harvest June 1 Jun 1 โ€“ Jul 20

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

Month-by-Month Timeline

MonthActivities
January Start Indoors
February Direct Sow
March Transplant Outdoors Direct Sow
April โ€”
May โ€”
June Harvest
July Harvest
August โ€”
September โ€”
October โ€”
November โ€”
December โ€”

Growing Conditions

โ˜€๏ธ Sun

Full Sun (6-8+ hours)

๐Ÿ’ง Water

1"/week ยท 2-3 times/week

๐Ÿ“… Days to Maturity

90โ€“120 days

๐Ÿงช Soil pH

Needs 6โ€“7.5 ยท Your soil: too_alkaline

๐Ÿ—บ๏ธ USDA Zone

Zone 9a

๐Ÿ“† Growing Season

277 days in Pinal County

Growing Tips for Amaranth in Pinal County

Direct sow Amaranth outdoors after February 23 in Pinal County when soil has warmed and frost danger has passed.

Sandy soil in Pinal County dries quickly โ€” mulch Amaranth with 2-3 inches of straw and water deeply 2-3 times per week rather than lightly every day.

With summer highs reaching 98ยฐF in Pinal County, provide afternoon shade for Amaranth and water deeply in the morning.

Pinal County receives only 16" of rain annually. Amaranth needs consistent moisture โ€” 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 Pinal County, AZ?

Pinal County is in Zone 9a with an average last frost of February 23. Plan your Amaranth planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Pinal County, AZ?

Pinal County, Arizona is in USDA Hardiness Zone 9a. The average last spring frost is February 23 and first fall frost is November 27.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Pinal County gardeners in Zone 9a organize planting dates, track what's growing, and never miss a planting window.

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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 Pinal County, AZ. Local conditions may vary. Last updated: April 2026.