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When to Plant Amaranth in Placer County, CA

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.

Placer County, California is in USDA Zone 8a. The average last spring frost is April 22 and the first fall frost is November 9, giving you a growing season of approximately 201 days.

At an elevation of 651 feet, Placer County receives approximately 25.3 inches of rainfall annually with predominantly loam soil. Summer highs average 85ยฐF, providing good warmth for Amaranth during the growing season.

Placer County, CA (Zone 8a) Long season
201 days
Last Spring Frost April 22
201 growing days
First Fall Frost November 9

Placer County Soil Profile

Soil Type

Loam

Soil pH

6.6-7.2

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (46 days to spare)
Start indoors: Feb 24 Transplant: Apr 28 🍅 Harvest: Jul 28 – Sep 15
Recommended (50%) ✓ Fits season (47 days to spare)
Start indoors: Mar 4 Transplant: May 6 🍅 Harvest: Aug 5 – Sep 23
Safe Start (90%) ✓ Fits season (41 days to spare)
Start indoors: Apr 9 Transplant: Jun 11 🍅 Harvest: Sep 10 – Oct 29

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 Placer County

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

Soil pH

Your soil pH (6.6โ€“7.2) is within Amaranth's preferred range (6.0โ€“7.5).

Soil Texture

The loam soil in Placer County is excellent for Amaranth โ€” good drainage, moisture retention, and nutrient holding capacity.

Drainage

Drainage is adequate for Amaranth.

Organic Matter

Organic matter is moderate (3.1%). 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
0.5″/week
You supply
0.9″/week
Watering frequency 2-3 times/week
Season total 1,656 gal / 100 sq ft
Drought risk

Water stress score is 8/10 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€” 5.2" 0" โ„๏ธ Dormant
Feb โ€” 5.3" 0" โ„๏ธ Dormant
Mar โ€” 4.2" 0" โ„๏ธ Dormant
Apr 4.3" 1.7" 2.6" ๐Ÿšฟ Regular watering
May 4.3" 0.7" 3.6" ๐Ÿšฟ Regular watering
Jun 4.3" 0.1" 4.2" ๐Ÿšฟ Regular watering
Jul 4.3" 0" 4.3" ๐Ÿšฟ Regular watering
Aug 4.3" 0" 4.3" ๐Ÿšฟ Regular watering
Sep 4.3" 0.2" 4.1" ๐Ÿšฟ Regular watering
Oct 4.3" 1.1" 3.2" ๐Ÿšฟ Regular watering
Nov 4.3" 2.4" 1.9" ๐Ÿ’ง Light watering
Dec โ€” 4.4" 0" โ„๏ธ Dormant

Water needs are for active growing months only (Aprโ€“Nov in Placer 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 ~1,444 GDD — county provides 2,763 GDD Excellent fit

Amaranth Planting Timeline โ€” Placer County, CA

Amaranth Planting Calendar

Activity When Date Range
Start Indoors March 4 Mar 4 โ€“ Mar 18
Transplant Outdoors May 6 May 6 โ€“ May 20
Direct Sow April 29 Apr 29 โ€“ May 20
Harvest August 5 Aug 5 โ€“ Sep 23

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

Month-by-Month Timeline

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

๐Ÿ—บ๏ธ USDA Zone

Zone 8a

๐Ÿ“† Growing Season

201 days in Placer County

Growing Tips for Amaranth in Placer County

Direct sow Amaranth outdoors after April 22 in Placer County when soil has warmed and frost danger has passed.

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 Placer County, CA?

Placer County is in Zone 8a with an average last frost of April 22. Plan your Amaranth planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Placer County, CA?

Placer County, California is in USDA Hardiness Zone 8a. The average last spring frost is April 22 and first fall frost is November 9.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Placer County gardeners in Zone 8a organize planting dates, track what's growing, and never miss a planting window.

Get Your Free Garden Planner →

Free download. Plan your entire garden season in minutes.

Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for Placer County, CA. Local conditions may vary. Last updated: April 2026.