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When to Plant Amaranth in Lake County, CA

Lake County, California Zone 9a May

Lake County, California gardeners: here's your May plan

We've pulled the most time-sensitive tasks for Lake County, California this May and put them front and centre. Tackle them in order.

Avg. last frost March 2
Avg. first frost November 27
Soil temp (4") 71°F
Watering Critical
Pest pressure High
Daylight 14.1 hrs
Coming up in June — start thinking about
  • 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.

Lake County, California is in USDA Zone 9a. The average last spring frost is March 2 and the first fall frost is November 27, giving you a growing season of approximately 270 days.

At an elevation of 154 feet, Lake County receives approximately 30.4 inches of rainfall annually with predominantly sandy loam soil. Summer highs average 83°F, so choose short-season varieties of Amaranth to ensure they mature before fall. Sandy soil warms quickly in spring — great for early planting — but Amaranth will need more frequent watering and organic matter to retain nutrients.

Lake County, CA (Zone 9a) Year-round
270 days
Last Spring Frost March 2
270 growing days
First Fall Frost November 27
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Lake County Soil Profile

Soil Type

Sandy Loam

Soil pH

6.1-6.9

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (131 days to spare)
Start indoors: Jan 3 Transplant: Feb 21 🍅 Harvest: May 23 – Jul 11
Recommended (50%) ✓ Fits season (123 days to spare)
Start indoors: Jan 19 Transplant: Mar 9 🍅 Harvest: Jun 8 – Jul 27
Safe Start (90%) ✓ Fits season (94 days to spare)
Start indoors: Mar 6 Transplant: Apr 24 🍅 Harvest: Jul 24 – Sep 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 Lake County

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

Soil pH

Your soil pH (6.1–6.9) is within Amaranth's preferred range (6.0–7.5).

Soil Texture

Sandy soil in Lake 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 moderate (2.7%). 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
0.5″/week
Watering frequency 1-2 times/week
Season total 1,267 gal / 100 sq ft

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 6.2" 0" ❄️ Dormant
Feb 6.5" 0" ❄️ Dormant
Mar 4.3" 4.6" 0" ✅ Rainfall sufficient
Apr 4.3" 2.7" 1.6" 💧 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" 1.1" 3.2" 🚿 Regular watering
Nov 4.3" 3" 1.3" 💧 Light watering
Dec 5.1" 0" ❄️ Dormant

Water needs are for active growing months only (Mar–Nov in 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 ~1,286 GDD — county provides 3,307 GDD Excellent fit

Amaranth Planting Timeline — Lake County, CA

Amaranth Planting Calendar

Activity When Date Range
Start Indoors January 19 Jan 19 – Feb 2
Transplant Outdoors March 9 Mar 9 – Mar 23
Direct Sow March 2 Mar 2 – Mar 23
Harvest June 8 Jun 8 – Jul 27

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

Month-by-Month Timeline

MonthActivities
January Start Indoors
February Start Indoors
March Transplant Outdoors Direct Sow
April
May
June Harvest
July Harvest
August
September
October
November
December
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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 9a

📆 Growing Season

270 days in Lake County

Growing Tips for Amaranth in Lake County

Direct sow Amaranth outdoors after March 02 in Lake County when soil has warmed and frost danger has passed.

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

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 Lake County, CA?

Lake County is in Zone 9a with an average last frost of March 2. Plan your Amaranth planting based on this frost date — see the calendar above for exact timing.

What planting zone is Lake County, CA?

Lake County, California is in USDA Hardiness Zone 9a. The average last spring frost is March 2 and first fall frost is November 27.

🌱

Your Lake County Garden Planner — Free

A 24-page printable planner built for Lake County (Zone 9a). 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 Lake County, CA. 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.