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When to Plant Cilantro in Kalawao County, HI

Kalawao County, Hawaii Zone 11a May

Kalawao County, Hawaii gardeners: here's your May plan

Your garden in Kalawao County, Hawaii is working on a schedule, even when you're not. Here's where you should be this May.

Soil temp (4") 83°F
Watering High
Pest pressure High
Daylight 13 hrs

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Cilantro is a dual-purpose herb providing fresh leaves (cilantro) and dried seeds (coriander). It bolts quickly in heat, producing flowers beloved by beneficial insects.

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 85°F, providing good warmth for Cilantro during the growing season. Clay soil retains moisture well for Cilantro, 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
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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 (85 days to spare)
Start indoors: Mar 18 Transplant: Apr 8 🍅 Harvest: May 20 – Jul 22
Recommended (50%) ✓ Fits season (85 days to spare)
Start indoors: Mar 18 Transplant: Apr 8 🍅 Harvest: May 20 – Jul 22
Safe Start (90%) ✓ Fits season (85 days to spare)
Start indoors: Mar 18 Transplant: Apr 8 🍅 Harvest: May 20 – Jul 22

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 Kalawao County

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

Soil pH

Your soil pH (5.7–6.7) overlaps with Cilantro's range (6.0–7.0), though not a perfect match.

Soil Texture

Your silty clay soil in Kalawao County is workable for Cilantro. Add compost annually to improve structure.

Organic Matter

Organic matter is moderate (3.9%). Annual compost additions will help Cilantro.

How to Plant Cilantro

0.5"
Planting Depth
8"
Between Plants
12"
Between Rows

Fall planting: Sow 8 weeks before your first frost date for a fall harvest.

Plant Water Budget

Plant needs
0.5″/week
Rainfall provides
0.3″/week
You supply
0.2″/week
Watering frequency Only during dry spells
Season total 675 gal / 100 sq ft
Drought risk

Water stress score is 6/10 — consider drought-tolerant varieties and mulching

Monthly Watering Guide for Cilantro

Cilantro needs approximately 0.5 inches of water per week (2.2" per month). Here's how your county's rainfall compares month by month.

Month Cilantro Needs Rainfall You Supplement Action
Jan 2.2" 4.1" 0" ✅ Rainfall sufficient
Feb 2.2" 3.1" 0" ✅ Rainfall sufficient
Mar 2.2" 3.4" 0" ✅ Rainfall sufficient
Apr 2.2" 2.6" 0" ✅ Rainfall sufficient
May 2.2" 1.6" 0.6" 💧 Light watering
Jun 2.2" 0.9" 1.3" 🚿 Regular watering
Jul 2.2" 0.7" 1.5" 🚿 Regular watering
Aug 2.2" 0.9" 1.3" 🚿 Regular watering
Sep 2.2" 1.4" 0.8" 💧 Light watering
Oct 2.2" 2.8" 0" ✅ Rainfall sufficient
Nov 2.2" 2.9" 0" ✅ Rainfall sufficient
Dec 2.2" 4" 0" ✅ Rainfall sufficient

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

Cilantro 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.

Cilantro needs ~688 GDD — county provides 5,018 GDD Excellent fit

Cilantro Planting Timeline — Kalawao County, HI

Cilantro Planting Calendar

Activity When Date Range
Start Indoors December 4 Dec 4 – Dec 18
Transplant Outdoors December 25 Dec 25 – Jan 8
Direct Sow December 11 Dec 11 – Jan 1
Harvest February 5 Feb 5 – Apr 9
Fall Sowing November 5 Nov 5 – Nov 19

Plant 0.5" deep · 8" apart · Rows 12" apart

Month-by-Month Timeline

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

☀️ Sun

Partial Shade (3-6 hours)

💧 Water

0.5"/week · Only during dry spells

📅 Days to Maturity

40–60 days

🧪 Soil pH

Needs 6–7 · Your soil: acceptable

🗺️ USDA Zone

Zone 11a

📆 Growing Season

364 days in Kalawao County

Growing Tips for Cilantro in Kalawao County

With Kalawao County's clay soil (37% clay), work in 3-4 inches of compost before planting Cilantro. Avoid tilling when soil is wet to prevent compaction.

Your generous 365.0-day season in Kalawao County allows multiple plantings of Cilantro. Sow every 20.0 days for continuous harvest.

Common pests for Cilantro in this region include carrot rust fly and parsleyworm. Use row covers early in the season and inspect plants weekly.

General growing tips

Succession sow every 2-3 weeks. Provide afternoon shade in warm weather. Harvest leaves before flowering or allow some plants to go to seed for coriander and self-sowing.

Companion Planting

Good Companions

Avoid Planting Near

  • Fennel

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Cilantro in Kalawao County, HI?

Kalawao County is in Zone 11a with an average last frost of January 1. Plan your Cilantro planting based on this frost date — 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.

🌱

Your Kalawao County Garden Planner — Free

A 24-page printable planner built for Kalawao County (Zone 11a). 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 Kalawao County, HI. 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.