When to Plant Corn in Honolulu County, HI
Corn is a warm-season grass grown for its sweet ears, which are best eaten soon after harvest. It is wind-pollinated and must be planted in blocks for good kernel fill.
Honolulu County, Hawaii is in USDA Zone 11b. 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 235 feet, Honolulu County receives approximately 44.3 inches of rainfall annually with predominantly silty clay soil. Summer highs average 88°F, providing good warmth for Corn during the growing season. Clay soil retains moisture well for Corn, but amend with compost to improve drainage and prevent root rot.
Honolulu County Soil Profile
Soil Type
Silty Clay
Soil pH
5.7-6.4
Drainage
Well Drained
Plant Planting Risk Windows
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 Honolulu County
How your county's soil matches Corn's growing requirements.
Soil pH
Your soil pH (5.7–6.4) overlaps with Corn's range (6.0–7.0), though not a perfect match.
Soil Texture
Your silty clay soil in Honolulu County is workable for Corn. Add compost annually to improve structure.
Organic Matter
Organic matter is moderate (3.6%). Annual compost additions will help Corn.
How to Plant Corn
How Much Corn to Grow
For a family of 4, plant approximately 60 corn plants in about 180 sq ft. In Honolulu County's 364-day season, you'll have plenty of time for a full harvest. Plan your garden layout →
Plant Water Budget
Water stress score is 6/10 — consider drought-tolerant varieties and mulching
Monthly Watering Guide for Corn
Corn needs approximately 1.5 inches of water per week (6.5" per month). Here's how your county's rainfall compares month by month.
| Month | Corn Needs | Rainfall | You Supplement | Action |
|---|---|---|---|---|
| Jan | 6.5" | 6.4" | 0.1" | 💧 Light watering |
| Feb | 6.5" | 4.7" | 1.8" | 💧 Light watering |
| Mar | 6.5" | 6.2" | 0.3" | 💧 Light watering |
| Apr | 6.5" | 3.9" | 2.6" | 💧 Light watering |
| May | 6.5" | 2.5" | 4" | 🚿 Regular watering |
| Jun | 6.5" | 1.3" | 5.2" | 🚿 Regular watering |
| Jul | 6.5" | 0.9" | 5.6" | 🚿 Regular watering |
| Aug | 6.5" | 1.3" | 5.2" | 🚿 Regular watering |
| Sep | 6.5" | 2.2" | 4.3" | 🚿 Regular watering |
| Oct | 6.5" | 4.4" | 2.1" | 💧 Light watering |
| Nov | 6.5" | 4.2" | 2.3" | 💧 Light watering |
| Dec | 6.5" | 6.2" | 0.3" | 💧 Light watering |
Water needs are for active growing months only (Jan–Dec in Honolulu County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.
Corn 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.
Corn Planting Timeline — Honolulu County, HI
Corn Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Direct Sow | January 8 | Jan 8 – Jan 29 |
| Harvest | March 12 | Mar 12 – May 7 |
Plant 1" deep · 12" apart · Rows 36" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | Direct Sow |
| February | — |
| March | Harvest |
| April | Harvest |
| May | Harvest |
| June | — |
| July | — |
| August | — |
| September | — |
| October | — |
| November | — |
| December | — |
Growing Conditions
☀️ Sun
Full Sun (6-8+ hours)
💧 Water
1.5"/week · 2-3 times/week
📅 Days to Maturity
60–100 days
🧪 Soil pH
Needs 6–7 · Your soil: acceptable
🗺️ USDA Zone
Zone 11b
📆 Growing Season
364 days in Honolulu County
Growing Tips for Corn in Honolulu County
With Honolulu County's clay soil (36% clay), work in 3-4 inches of compost before planting Corn. Avoid tilling when soil is wet to prevent compaction.
Common pests for Corn in this region include corn earworm and corn borers. Use row covers early in the season and inspect plants weekly.
General growing tips
Plant in blocks of at least 4 rows rather than single rows for proper pollination. Direct sow after soil reaches 60F. Side-dress with nitrogen when plants are knee-high.
Companion Planting
Good Companions
Avoid Planting Near
Check more plant combinations with our Companion Planting Checker →
Corn in Other Locations
Frequently Asked Questions
When should I plant Corn in Honolulu County, HI?
Honolulu County is in Zone 11b with an average last frost of January 1. Plan your Corn planting based on this frost date — see the calendar above for exact timing.
What planting zone is Honolulu County, HI?
Honolulu County, Hawaii is in USDA Hardiness Zone 11b. The average last spring frost is January 1 and first fall frost is December 31.
Plan Your Garden with Confidence
Get our free Garden Planner — designed to help Honolulu County gardeners in Zone 11b organize planting dates, track what's growing, and never miss a planting window.
Get Your Free Garden Planner →Free download. Plan your entire garden season in minutes.