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When to Plant Amaranth in Kalawao County, HI

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.

Kalawao County, Hawaii is in USDA Zone 11a. The average last spring frost is January 1 and the first fall frost is December 31, giving you a growing season of approximately 364 days.

At an elevation of 402 feet, Kalawao County receives approximately 28.4 inches of rainfall annually with predominantly silty clay soil. Summer highs average 85ยฐF, providing good warmth for Amaranth during the growing season. Clay soil retains moisture well for Amaranth, but amend with compost to improve drainage and prevent root rot.

Kalawao County, HI (Zone 11a) Year-round
364 days
Last Spring Frost January 1
364 growing days
First Fall Frost December 31

Kalawao County Soil Profile

Soil Type

Silty Clay

Soil pH

5.7-6.7

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (36 days to spare)
Start indoors: Mar 4 Transplant: Apr 22 🍅 Harvest: Jul 22 – Sep 9
Recommended (50%) ✓ Fits season (36 days to spare)
Start indoors: Mar 4 Transplant: Apr 22 🍅 Harvest: Jul 22 – Sep 9
Safe Start (90%) ✓ Fits season (36 days to spare)
Start indoors: Mar 4 Transplant: Apr 22 🍅 Harvest: Jul 22 – Sep 9

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.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
0.3″/week
You supply
0.8″/week
Watering frequency 2-3 times/week
Season total 2,624 gal / 100 sq ft
Drought risk

Water stress score is 6/10 โ€” consider drought-tolerant varieties and mulching

Amaranth needs ~1,444 GDD — county provides 5,018 GDD Excellent fit

Amaranth Planting Timeline โ€” Kalawao County, HI

Amaranth Planting Calendar

Activity When Date Range
Start Indoors November 20 Nov 20 โ€“ Dec 4
Transplant Outdoors January 8 Jan 8 โ€“ Jan 22
Direct Sow January 1 Jan 1 โ€“ Jan 22
Harvest April 9 Apr 9 โ€“ May 28

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

Month-by-Month Timeline

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

Growing Conditions

Sun

Full Sun (6-8+ hours)

Water

Moderate โ€” regular watering

Days to Maturity

90โ€“120 days

Soil pH

6 โ€“ 7.5

USDA Zone

Zone 11a

Growing Season

364 days

Growing Tips for Kalawao County

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

Level Up Your Garden

Frequently Asked Questions

When should I plant Amaranth in Kalawao County, HI?

Kalawao County is in Zone 11a with an average last frost of January 1. Plan your Amaranth planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Kalawao County, HI?

Kalawao County, Hawaii is in USDA Hardiness Zone 11a. The average last spring frost is January 1 and first fall frost is December 31.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Kalawao County gardeners in Zone 11a organize planting dates, track what's growing, and never miss a planting window.

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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 Kalawao County, HI. Local conditions may vary. Last updated: April 2026.