Hawaii · zones 12a–12a
When to plant tomatoes in Hawaii.
Sow or transplant between Jan 8 to Mar 10 in a typical year, keyed to Hawaii's median last frost around Jan 1. Dates below are state medians; your ZIP code shifts them by days to weeks.
The 2026 windows
Tomatoes dates for a typical Hawaii season.
1 · Start indoors
Nov 27 to Jan 27
About 6 weeks before set-out. Warm spot, real light.
2 · Set out
Jan 8 to Mar 10
Keyed to the ~Jan 1 last frost. Sow 0.25" deep, 24" apart.
Harvest
~73 days later
~12 lb per plant over ~8 weeks.
Hawaii spans more than one climate: Zone 12 is the most common zone, but the state runs 12a to 12a. That's why the planner works from your ZIP code's frost dates, not your zone: mountain and coastal gardens in the same state can be three weeks apart.
Hawaii growing notes
One 73-day tomato planting here has to out-manage three leaf diseases with no cold snap ever stepping in to help.
Only one shot, so staking and spacing do the early work
Zone 12a's 364-day stretch with no true close-out date means slicing tomatoes get one continuous planting instead of a spring round and a fall round. Space plants 24 inches apart in the row, and a healthy plant should return around 12 pounds over its life. With no second window opening behind this one, getting the bed right the first time matters more than it would on a crop that gets replanted every few weeks.
That single planting also means at least 73 days of leaves exposed to whatever moisture the site delivers, and Hawaii splits sharply on that point. A windward bed catching regular rain needs airflow more than a leeward one does, so open the plant up early: stake or cage it as soon as it needs support, and strip off the lowest leaves once the first fruit sets. A sprawling, unstaked plant holds humidity against its own lower leaves for months instead of weeks, handing early blight, late blight, and Septoria leaf spot the head start described next.
Early blight, late blight, and Septoria all read from the bottom leaves up
Early blight, late blight, and Septoria leaf spot are the three fungal problems that show up on tomatoes here, and none of them wait for a particular temperature, only wet leaves and time to work. Check the oldest leaves near the base first, once a week: concentric brown rings circled in yellow are early blight, dark blotches that look greasy and spread within days point to late blight, and small tan spots ringed in dark brown scattered across older leaves are Septoria. Whichever shows up, pull the infected leaves and carry them out of the bed rather than dropping them at the base of the plant.
Because nothing here resets that cycle for a season, the habit that pays off most is keeping the bottom foot of the plant bare and mulched, so a hard rain cannot splash spores up out of the soil and onto healthy leaves. Kewalo, a determinate variety bred at the University of Hawaii specifically for lowland growing conditions, is worth a look for a grower who wants a plant with a head start built in; it will not stop the three leaf diseases above, but it was developed for exactly this kind of warm, humid ground.
Flea beetles hit the transplant, aphids move in once it's growing hard
Flea beetles are the pest to watch in the first few weeks after transplant: small, dark beetles that spring away the instant a leaf is touched, which is often the clue that gives them away before the insect itself is ever spotted. They leave young leaves stippled with pinhead-sized holes, and because a new transplant has so little leaf area to spare, that damage matters more now than it will once the plant is established. A lightweight cover held over the bed for the first two or three weeks keeps them off without needing to spray anything on a plant this small.
Aphids take over once the plant is climbing and pushing new growth every week, clustering thickest on the newest leaves at the top of the vine. Because this planting runs for months rather than weeks, that growing tip needs a look on a regular basis, not just once. A brisk rinse from the hose knocks most colonies down before they build into a real problem, and watching for ants working the stem is worth doing too, since ants farm aphids for the honeydew and moving them off the plant often does more good than a spray would.
In Hawaii: watch for
The pests that find tomatoes here.
With about 364 frost-free days, tomato, slicing spends longer in the ground here than in most of the country, which widens the window in which aphids can find it. Scout weekly from midseason and act on the first signs.
Clusters on new growth, sticky leaves, curling tips.
Organic fix: Blast with water, then insecticidal soap or neem.
Dark spots with concentric rings, starting on the lowest, oldest leaves.
Organic fix: Remove affected leaves, mulch to stop soil splash, space for airflow.
Greasy, water-soaked blotches in cool, wet spells. No rings, and not bottom-up.
Organic fix: Pull infected plants fast, keep leaves dry, use neem as a preventive.
Septoria leaf spot
Many small tan spots with dark brown edges, low leaves first, no rings inside.
Organic fix: Strip the lowest leaves, mulch against soil splash, stake for airflow.
Tiny shot-hole pits peppering young leaves.
Organic fix: Float a row cover on seedlings; dust with diatomaceous earth.
Your season math: Hawaii gives tomatoes about 364 frost-free days, and it needs roughly 73 days to a first harvest. It's a one-planting crop, so time that single sowing well.
Planting tomatoes in Hawaii: questions
When should I plant tomatoes in Hawaii?+
In a typical Hawaii year, sow tomatoes or set out transplants between Jan 8 to Mar 10, keyed to the state's median last frost around Jan 1. Your exact dates shift with your ZIP code and microclimate.
When do I start tomatoes seeds indoors in Hawaii?+
Start seeds inside about 6 weeks before set-out: roughly Nov 27 to Jan 27 for a typical Hawaii season.
What USDA zone is Hawaii?+
Hawaii spans zones 12a–12a, mostly zone 12. But frost dates, not zones, set planting time. The free planner uses your ZIP code's actual frost dates.
How many tomatoes plants do I need?+
Depends who you're feeding. The crop page has exact counts per household size, or the free planner does the math for your family in about 60 seconds.