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When to Plant Amaranth in Carson, WA

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.

Carson, Washington is in USDA Zone 8a. The average last spring frost is April 18 and the first fall frost is October 19, giving you a growing season of approximately 184 days.

At an elevation of 16 feet, Skamania County receives approximately 43 inches of rainfall annually with predominantly silt loam soil. Summer highs average 79°F, so choose short-season varieties of Amaranth to ensure they mature before fall.

Carson, WA (Zone 8a) Moderate season
184 days
Last Spring Frost April 18
184 growing days
First Fall Frost October 19

Carson Soil Profile

Soil Type

Silt Loam

Soil pH

5.6-6.2

Drainage

Well Drained

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 6.5" 0" ❄️ Dormant
Feb 4.3" 0" ❄️ Dormant
Mar 3.8" 0" ❄️ Dormant
Apr 4.3" 3.6" 0.7" 💧 Light watering
May 4.3" 2.1" 2.2" 🚿 Regular watering
Jun 4.3" 1.7" 2.6" 🚿 Regular watering
Jul 4.3" 0.7" 3.6" 🚿 Regular watering
Aug 4.3" 0.7" 3.6" 🚿 Regular watering
Sep 4.3" 1.8" 2.5" 🚿 Regular watering
Oct 4.3" 3.3" 1" 💧 Light watering
Nov 7.4" 0" ❄️ Dormant
Dec 7.1" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Skamania County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.

Amaranth Planting Timeline — Carson, WA

Amaranth Planting Calendar

Activity When Date Range
Start Indoors February 28 Feb 28 – Mar 14
Transplant Outdoors May 2 May 2 – May 16
Direct Sow April 25 Apr 25 – May 16
Harvest August 1 Aug 1 – Sep 19

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

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

Moderate — regular watering

📅 Days to Maturity

90–120 days

🧪 Soil pH

Needs 6–7.5 · Your soil: N/A

🗺️ USDA Zone

Zone 8a

📆 Growing Season

184 days in Skamania County

Growing Tips for Carson

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 →

🌱

Your Skamania County Garden Planner — Free

A 22-page printable planner built for Skamania County (Zone 8a). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.

Instant PDF download. No spam, unsubscribe any time.

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