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When to plant Amaranth in Isleton, CA

Isleton's climate puts the Amaranth spring window between February 12 and March 5. aim for a steady week of warm soil before planting.

When to Plant Amaranth in Isleton, CA

Sacramento County, California Zone 9b June

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A quick June briefing for Sacramento County, California gardeners — what's urgent, what's next, and what can wait.

Avg. last frost February 12
Avg. first frost December 1
Soil temp (4") 87°F
Watering Critical
Pest pressure High
Daylight 14.7 hrs
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  • First harvests: 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.

Isleton, California is in USDA Zone 9b. The average last spring frost is February 12 and the first fall frost is December 1, giving you a growing season of approximately 292 days.

At an elevation of 263 feet, Sacramento County receives approximately 33.2 inches of rainfall annually with predominantly loam soil. Summer highs average 90°F, providing good warmth for Amaranth during the growing season.

Isleton, CA (Zone 9b) Year-round
292 days
Last Spring Frost February 12
292 growing days
First Fall Frost December 1

Isleton Soil Profile

Soil Type

Loam

Soil pH

6.4-7.1

Drainage

Well Drained

Amaranth Planting Risk Windows

Early Start (70% safe) ✓ Fits season (156 days to spare)
Start indoors: Dec 15 Transplant: Feb 2 🍅 Harvest: May 4 – Jun 22
Recommended (50%) ✓ Fits season (145 days to spare)
Start indoors: Jan 1 Transplant: Feb 19 🍅 Harvest: May 21 – Jul 9
Safe Start (90%) ✓ Fits season (111 days to spare)
Start indoors: Feb 23 Transplant: Apr 13 🍅 Harvest: Jul 13 – Aug 31

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 Isleton

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

Soil pH

Your soil pH (6.4–7.1) is within Amaranth's preferred range (6.0–7.5).

Soil Texture

The loam soil in Sacramento County is excellent for Amaranth — good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is moderate (2.4%). 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
0.5″/week
You supply
0.6″/week
Watering frequency 1-2 times/week
Season total 1,640 gal / 100 sq ft
Drought risk

Water stress score is 8/10 — 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 6.1" 0" ❄️ Dormant
Feb 4.3" 7.5" 0" ✅ Rainfall sufficient
Mar 4.3" 5.7" 0" ✅ Rainfall sufficient
Apr 4.3" 2.5" 1.8" 💧 Light watering
May 4.3" 0.8" 3.5" 🚿 Regular watering
Jun 4.3" 0.2" 4.1" 🚿 Regular watering
Jul 4.3" 0" 4.3" 🚿 Regular watering
Aug 4.3" 0" 4.3" 🚿 Regular watering
Sep 4.3" 0.3" 4" 🚿 Regular watering
Oct 4.3" 1.4" 2.9" 🚿 Regular watering
Nov 4.3" 2.7" 1.6" 💧 Light watering
Dec 4.3" 5.9" 0" ✅ Rainfall sufficient

Water needs are for active growing months only (Feb–Dec in Sacramento 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 ~1,838 GDD — county provides 5,127 GDD Excellent fit

Amaranth Planting Timeline — Isleton, CA

Amaranth Planting Calendar

Activity When Date Range
Start Indoors January 1 Jan 1 – Jan 15
Transplant Outdoors February 19 Feb 19 – Mar 5
Direct Sow February 12 Feb 12 – Mar 5
Harvest May 21 May 21 – Jul 9

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

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1"/week · 1-2 times/week

📅 Days to Maturity

90–120 days

🧪 Soil pH

Needs 6–7.5 · Your soil: ideal

🗺️ USDA Zone

Zone 9b

📆 Growing Season

292 days in Sacramento County

Growing Tips for Amaranth in Isleton

Direct sow Amaranth outdoors after February 12 in Sacramento 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 →

When should I plant Amaranth in Isleton, CA?

In Isleton, CA, plant Amaranth after the last frost (around February 12) and before the first frost (around December 1). Best results when soil holds above 50°F.

What growing zone is Isleton, CA for Amaranth?

Isleton sits in USDA Zone 9b. Amaranth grows reliably in zones 2a through 11b, so it's a good fit here.

Can Amaranth grow in Isleton's climate?

Yes — Amaranth grows well in Isleton's temperate climate. Isleton averages a 293-day frost-free season, with last frost around February 12 and first frost around December 1.

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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 Sacramento County, CA. Local conditions may vary. Last updated: June 2026.