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When to Plant Calabash in Kalawao County, HI

Kalawao County, Hawaii Zone 11a May

May to-do list for Kalawao County, Hawaii

A quick May briefing for Kalawao County, Hawaii gardeners — what's urgent, what's next, and what can wait.

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

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Calabash (bottle gourd) is a tropical vine producing edible young fruits used in Asian and African cooking. Mature dried fruits serve as natural containers and utensils.

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 Calabash during the growing season. Clay soil retains moisture well for Calabash, 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 15 – Sep 9
Recommended (50%) ✓ Fits season (36 days to spare)
Start indoors: Mar 4 Transplant: Apr 22 🍅 Harvest: Jul 15 – Sep 9
Safe Start (90%) ✓ Fits season (36 days to spare)
Start indoors: Mar 4 Transplant: Apr 22 🍅 Harvest: Jul 15 – 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.

Soil Compatibility in Kalawao County

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

Soil pH

Your soil pH (5.7–6.7) overlaps with Calabash's range (6.0–7.5), though not a perfect match.

Soil Texture

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

Organic Matter

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

How to Plant Calabash

1"
Planting Depth
30"
Between Plants
42"
Between Rows

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 — consider drought-tolerant varieties and mulching

Monthly Watering Guide for Calabash

Calabash needs approximately 1 inches of water per week (4.3" per month). Here's how your county's rainfall compares month by month.

Month Calabash Needs Rainfall You Supplement Action
Jan 4.3" 4.1" 0.2" 💧 Light watering
Feb 4.3" 3.1" 1.2" 💧 Light watering
Mar 4.3" 3.4" 0.9" 💧 Light watering
Apr 4.3" 2.6" 1.7" 💧 Light watering
May 4.3" 1.6" 2.7" 🚿 Regular watering
Jun 4.3" 0.9" 3.4" 🚿 Regular watering
Jul 4.3" 0.7" 3.6" 🚿 Regular watering
Aug 4.3" 0.9" 3.4" 🚿 Regular watering
Sep 4.3" 1.4" 2.9" 🚿 Regular watering
Oct 4.3" 2.8" 1.5" 💧 Light watering
Nov 4.3" 2.9" 1.4" 💧 Light watering
Dec 4.3" 4" 0.3" 💧 Light watering

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.

Calabash 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.

Calabash needs ~1,375 GDD — county provides 5,018 GDD Excellent fit

Calabash Planting Timeline — Kalawao County, HI

Calabash Planting Calendar

Activity When Date Range
Start Indoors November 20 Nov 20 – Dec 4
Transplant Outdoors January 8 Jan 8 – Jan 22
Direct Sow January 1 Jan 1 – Jan 22
Harvest April 2 Apr 2 – May 28

Plant 1" deep · 30" apart · Rows 42" apart

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1"/week · 2-3 times/week

📅 Days to Maturity

80–120 days

🧪 Soil pH

Needs 6–7.5 · Your soil: acceptable

🗺️ USDA Zone

Zone 11a

📆 Growing Season

364 days in Kalawao County

Growing Tips for Calabash in Kalawao County

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

Common pests for Calabash in this region include squash vine borer and cucumber beetles. Use row covers early in the season and inspect plants weekly.

General growing tips

Start seeds indoors 4 weeks early. Provide a very strong trellis for heavy fruits. Harvest young for cooking or let mature on the vine for crafts. Requires a long, warm season.

Companion Planting

Good Companions

Avoid Planting Near

  • Potatoes

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Calabash in Kalawao County, HI?

Kalawao County is in Zone 11a with an average last frost of January 1. Plan your Calabash 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.