When to Plant Sweet Potatoes in Hawaii
Published: April 24, 2026
Hawaii gardeners in Zone 12a have essentially year-round growing for sweet potato. Heat and humidity let you grow sweet potato through most months; the main limiting factor is wet-season disease pressure. This guide gives exact dates for Hawaii based on your local frost calendar.
Sweet Potato Planting Dates for Hawaii
| Last frost (average) | Frost-free |
| Transplant outdoors | Year-round (October–March is primary window) |
| Direct sow outdoors | Year-round (October–March is primary window) |
| Expect first harvest | 45–120 days after planting |
| First fall frost (average) | Frost-free |
⚠ Plant sweet potato slips 2–3 weeks after last frost when soil is consistently above 60°F. Needs 90–120 days of warm weather. Best in Zones 5–11.
Growing Sweet Potatoes in Hawaii's Climate
Hawaii's tropical climate gives sweet potato year-round potential, but not all months are equal. Wet season (May through October in most of Hawaii) brings disease pressure that can destroy a sweet potato crop within days if fungal conditions align. Dry season (November through April) is the primary productive window.
Soil drainage matters more in tropical climates than almost anywhere else. Raised beds or heavily amended beds with 50% compost content drain rainfall quickly and keep sweet potato roots oxygenated during heavy storms. Flat beds in native clay soil often fail the first wet season.
Common sweet potato pests to watch for in Hawaii include Sweet Potato Weevil and Wireworm. The first line of defense is companion planting: Bush Bean and Pea planted nearby discourage several of these pests by confusing host-plant identification or repelling adults before they can lay eggs. Weekly garden walks in the early morning catch problems when they're still manageable.
Sweet Potato Garden Calendar for Hawaii
| Month | Task | Notes |
|---|---|---|
| January | First harvests | Early transplants reach harvest size |
| February | Main harvest month | Peak production month in tropical climate |
| March | Continue harvests | Last window for new plantings before wet season |
| April | Finish harvests | Wet season approaching — harvest ripe crops |
| May ← | Clear beds | Disease pressure rises with wet season; warm-season ornamentals now |
| June | — | |
| July | — | |
| August | — | |
| September | — | |
| October | Prime planting window opens | Direct sow or transplant sweet potato; dry season begins |
| November | Main planting month | Peak planting window for best harvests |
| December | Continue successions | Plant every 2–3 weeks for staggered harvest |
Sweet Potato Growing Tips for Hawaii Gardeners
- •Order slips in early spring from a seed company; plant within 24 hours of arrival in pre-warmed soil.
- •Form raised ridges or mounds 10 inches tall — sweet potatoes size up best in loose, warm, well-drained soil.
- •Hawaii's tropical climate favors planting sweet potato in dry season (October through April). Wet season plantings are destroyed by fungal disease within weeks.
- •Black plastic mulch warms soil quickly in northern climates and can add 2 weeks to the effective growing season.
Companion Planting for Sweet Potatoes in Hawaii
In Hawaii's tropical climate, planting sweet potato with Bush Bean and Pea helps deter pests and improve soil. Avoid planting near Squash and Tomato, which inhibit sweet potato growth through root chemistry or shared pest pressure. See the full sweet potato companion planting guide for the complete list.
Sweet Potatoes Planting Dates by City in Hawaii
Top cities in Hawaii — select for city-level frost dates and planting calendars.
Frequently Asked Questions
When should I plant sweet potato in Hawaii?
In Hawaii (Zone 12a), direct sow sweet potato around Year-round (October–March is primary window) — 3 weeks after the state's average last frost of Frost-free.
What is the last frost date in Hawaii?
Hawaii's average last frost date is Frost-free in the state's most common Zone 12a. Frost dates vary by city — higher elevations and northern counties run 1 to 3 weeks later than the state average. See the city list below for city-level frost dates.
Can I grow sweet potato year-round in Hawaii?
Yes, Hawaii's frost-free climate supports year-round sweet potato growing. October through March is the primary productive window; summer heat and wet-season fungal pressure limit what you can grow June through September.
What sweet potato varieties grow best in Hawaii?
For Hawaii's Zone 12a, consult a local nursery or extension office for sweet-potatoes variety recommendations.
When do I start sweet potato seeds indoors in Hawaii?
Sweet potato does not need indoor starting in Hawaii — direct sow around Year-round (October–March is primary window) once soil reaches 60°F. Indoor starting is not recommended for this crop because sweet potato transplants poorly.