When to Plant Kai Lan in Honolulu County, HI
Kai lan (Chinese broccoli) is a brassica grown for its thick, glossy stems and small flower buds. It has a slightly bitter, broccoli-like flavor essential in Cantonese cooking.
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 Kai Lan during the growing season. Clay soil retains moisture well for Kai Lan, 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.
Plant Water Budget
Water stress score is 6/10 — consider drought-tolerant varieties and mulching
Kai Lan Planting Timeline — Honolulu County, HI
Kai Lan Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | December 4 | Dec 4 – Dec 18 |
| Transplant Outdoors | January 1 | Jan 1 – Jan 15 |
| Direct Sow | December 11 | Dec 11 – Jan 1 |
| Fall Sowing | November 5 | Nov 5 – Nov 19 |
| Harvest | February 19 | Feb 19 – Mar 19 |
Plant 0.5" deep · 6" apart · Rows 12" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | Transplant Outdoors Direct Sow |
| February | Harvest |
| March | Harvest |
| April | — |
| May | — |
| June | — |
| July | — |
| August | — |
| September | — |
| October | — |
| November | Fall Sowing |
| December | Start Indoors Direct Sow |
Growing Conditions
Sun
Full Sun (6-8+ hours)
Water
Moderate — regular watering
Days to Maturity
45–60 days
Soil pH
6 – 7.5
USDA Zone
Zone 11b
Growing Season
364 days
Growing Tips for Honolulu County
Direct sow in spring or fall. Harvest when flower buds first appear but before they open. Cut stems at the base to encourage side shoots. Prefers cool weather.
Companion Planting
Good Companions
Avoid Planting Near
Level Up Your Garden
Kai Lan in Other Locations
Frequently Asked Questions
When should I plant Kai Lan in Honolulu County, HI?
Honolulu County is in Zone 11b with an average last frost of January 1. Plan your Kai Lan 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.
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