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When to Plant Amaranth in La Paz 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.

La Paz County, Arizona is in USDA Zone 9b. The average last spring frost is February 2 and the first fall frost is December 6, giving you a growing season of approximately 307 days.

At an elevation of 4,875 feet, La Paz County receives approximately 17.4 inches of rainfall annually with predominantly sandy loam soil. Summer highs average 105ยฐF, 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.

La Paz County, AZ (Zone 9b) Year-round
307 days
Last Spring Frost February 2
307 growing days
First Fall Frost December 6

La Paz County Soil Profile

Soil Type

Sandy Loam

Soil pH

7.2-8.3

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (172 days to spare)
Start indoors: Dec 7 Transplant: Jan 25 🍅 Harvest: Apr 26 – Jun 14
Recommended (50%) ✓ Fits season (160 days to spare)
Start indoors: Dec 22 Transplant: Feb 9 🍅 Harvest: May 11 – Jun 29
Safe Start (90%) ✓ Fits season (156 days to spare)
Start indoors: Jan 16 Transplant: Mar 6 🍅 Harvest: Jun 5 – Jul 24

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 La Paz County

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

Soil pH

Your soil pH (7.2โ€“8.3) is more alkaline than Amaranth prefers (6.0โ€“7.5). Add sulfur or peat moss to lower pH.

Soil Texture

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

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
0.9″/week
Watering frequency 2-3 times/week
Season total 2,509 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€” 1.3" 0" โ„๏ธ Dormant
Feb 4.3" 0.9" 3.4" ๐Ÿšฟ Regular watering
Mar 4.3" 1" 3.3" ๐Ÿšฟ Regular watering
Apr 4.3" 0.6" 3.7" ๐Ÿšฟ Regular watering
May 4.3" 0.4" 3.9" ๐Ÿšฟ Regular watering
Jun 4.3" 0.7" 3.6" ๐Ÿšฟ Regular watering
Jul 4.3" 2.5" 1.8" ๐Ÿ’ง Light watering
Aug 4.3" 3.7" 0.6" ๐Ÿ’ง Light watering
Sep 4.3" 2.5" 1.8" ๐Ÿ’ง Light watering
Oct 4.3" 1.6" 2.7" ๐Ÿšฟ Regular watering
Nov 4.3" 1" 3.3" ๐Ÿšฟ Regular watering
Dec 4.3" 1.2" 3.1" ๐Ÿšฟ Regular watering

Water needs are for active growing months only (Febโ€“Dec in La Paz 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 ~3,019 GDD — county provides 8,855 GDD Excellent fit

Amaranth Planting Timeline โ€” La Paz County, AZ

Amaranth Planting Calendar

Activity When Date Range
Start Indoors December 22 Dec 22 โ€“ Jan 5
Transplant Outdoors February 9 Feb 9 โ€“ Feb 23
Direct Sow February 2 Feb 2 โ€“ Feb 23
Harvest May 11 May 11 โ€“ Jun 29

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

Month-by-Month Timeline

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

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 9b

๐Ÿ“† Growing Season

307 days in La Paz County

Growing Tips for Amaranth in La Paz County

Direct sow Amaranth outdoors after February 02 in La Paz County when soil has warmed and frost danger has passed.

Sandy soil in La Paz 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 105ยฐF in La Paz County, provide afternoon shade for Amaranth and water deeply in the morning.

La Paz County receives only 17" 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 La Paz County, AZ?

La Paz County is in Zone 9b with an average last frost of February 2. Plan your Amaranth planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is La Paz County, AZ?

La Paz County, Arizona is in USDA Hardiness Zone 9b. The average last spring frost is February 2 and first fall frost is December 6.

๐ŸŒฑ

Plan Your Garden with Confidence

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