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When to Plant Amaranth in Mapleton, OR

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.

Mapleton, Oregon is in USDA Zone 8b. The average last spring frost is April 21 and the first fall frost is October 25, giving you a growing season of approximately 187 days.

At an elevation of 48 feet, Lane County receives approximately 50.6 inches of rainfall annually with predominantly silt loam soil. Summer highs average 81°F, so choose short-season varieties of Amaranth to ensure they mature before fall. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Amaranth root diseases.

Mapleton, OR (Zone 8b) Moderate season
187 days
Last Spring Frost April 21
187 growing days
First Fall Frost October 25

Mapleton Soil Profile

Soil Type

Silt Loam

Soil pH

5.7-6.4

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 7.6" 0" ❄️ Dormant
Feb 5.3" 0" ❄️ Dormant
Mar 5.3" 0" ❄️ Dormant
Apr 4.3" 4" 0.3" 💧 Light watering
May 4.3" 2.5" 1.8" 💧 Light watering
Jun 4.3" 1.6" 2.7" 🚿 Regular watering
Jul 4.3" 0.8" 3.5" 🚿 Regular watering
Aug 4.3" 0.9" 3.4" 🚿 Regular watering
Sep 4.3" 2" 2.3" 🚿 Regular watering
Oct 4.3" 4.3" 0" ✅ Rainfall sufficient
Nov 8.3" 0" ❄️ Dormant
Dec 8" 0" ❄️ Dormant

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

Amaranth Planting Timeline — Mapleton, OR

Amaranth Planting Calendar

Activity When Date Range
Start Indoors March 3 Mar 3 – Mar 17
Transplant Outdoors May 5 May 5 – May 19
Direct Sow April 28 Apr 28 – May 19
Harvest August 4 Aug 4 – Sep 22

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

Month-by-Month Timeline

MonthActivities
January
February
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 8b

📆 Growing Season

187 days in Lane County

Growing Tips for Mapleton

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 Lane County Garden Planner — Free

A 22-page printable planner built for Lane County (Zone 8b). 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 Lane County, OR. Local conditions may vary. Last updated: June 2026.