Garlic is the hardest crop in this whole group to grow well in Zone 12, and it deserves an honest warning: garlic forms bulbs best after a cold period, and a zone with winter lows of 50 to 60°F gives it almost no chilling at all. Planted in the coolest months, softneck varieties can still produce small bulbs — or single round bulbs that never split — and many tropical gardeners grow garlic mainly for its green shoots. Go in with realistic expectations and you will not be disappointed.
The Zone 12 challenge is heat. These are cool-season crops, and in a frost-free tropical zone the coolest months are short — plant by the coolest part of the year, give afternoon shade, and accept that the season is brief and the harvest smaller than in a cool climate.
Zone 12 at a glance
USDA Zone 12 covers the warmest lowland parts of Hawaii and Puerto Rico. Winters are very mild, with average winter lows of 50 to 60°F, frost is unknown, and the growing season runs all year. Zone 12 has no average last spring frost and no average first autumn frost — it is frost-free year-round — so planting dates here are averages and guidance, not exact dates for any one garden; check your local extension service before planting.
| Detail | Zone 12 guidance |
|---|---|
| Average winter low | 50 to 60°F |
| Average last spring frost | frost-free (no frost dates) |
| Average first autumn frost | frost-free (no frost dates) |
| Days to germination | 7–14 days |
| Days to maturity | 180–240 days |
| Sowing | direct sow |
| Sun | full sun |
| Soil pH | 6.0–7.0 |
| Spacing | 6 inches |
| Water needs | low |
| Cold tolerance | hardy |
When to plant garlic in Zone 12
Plant garlic in Zone 12 in the coolest months only, roughly December through February. Cloves sprout in 7–14 days and the crop matures in 180–240 days, so a sowing made in December is ready around June to August. Zone 12 is frost-free, so there are no last or first frost dates — check your local extension service for advice on your own microclimate. Sown outside the cool window, this crop bolts, turns bitter or fails to size up in the heat, so treat the coolest months as the whole season and plan other crops for the hot months.
The planting calendar hub and the December in Zone 12 month guide show what else is happening at planting time.
Starting garlic in Zone 12
Plant garlic direct in the coolest months, pushing individual cloves into well-drained soil, pointed end up, spaced 6 inches apart. Garlic takes 180–240 days to mature, so a December planting is not ready until well into the following summer — plan the bed accordingly, and choose softneck varieties, which cope better with warm winters than hardneck types.
See also when to plant garlic in Zone 11 for the same crop in a slightly cooler zone.
Soil, spacing, sun and water
Garlic needs full sun and rich, very well-drained soil with a pH of 6.0–7.0 — wet soil rots the bulbs. Dig in well-rotted compost before planting, space cloves 6 inches apart, and mulch lightly to keep the soil cool and moist without staying soggy. They need full sun and a soil pH of 6.0–7.0. Water needs are low: water deeply and regularly at the base, in the morning, so leaves dry before night. The germination time calculator can help you plan the bed before you plant.
Companion planting
Marigolds, basil, onions and lettuce are good companions for garlic, and garlic itself is valued as a companion for many crops — its strong scent is traditionally planted around roses and vegetables alike. Lettuce fills the ground between young garlic plants in the cooler months. The companion planting finder can suggest combinations for your whole bed, and our guide to when to plant onions in Zone 12 shows another crop that shares the same planting windows.
Pests and problems
The common pests and problems to watch for with garlic are aphids, slugs, cutworms. Aphids cluster on soft new growth and leaf undersides; wash them off with a strong jet of water and encourage ladybirds. Slugs feed at night, leaving ragged holes and slime trails; water in the morning and keep the bed clear of debris. Cutworms chew through young stems at soil level overnight; a cardboard collar around each seedling stops them. Your local extension service can confirm an identification if the damage is severe.
Harvest and storage
Harvest garlic when the lower leaves yellow and the plant starts to die back — do not wait until all the leaves are dead, or the bulb splits apart in the soil. Lift carefully with a fork, because pulling tears the bulb, and expect smaller bulbs than in a cold climate. Cure garlic in a warm, airy, shaded place for two to three weeks until the necks are dry, then store the bulbs in a cool, dark, airy spot. In a humid climate, check regularly for mould and use the bulbs within a few months.
Frequently asked questions
When should I plant garlic in Zone 12?
Plant garlic in Zone 12 in the coolest months only, roughly December through February. Zone 12 is frost-free year-round, so there are no last or first frost dates — plant by the heat and the wet and dry seasons, and check your local extension service for your own microclimate.
Does garlic need cold weather to form bulbs?
Yes — garlic bulbs split into cloves best after a period of cold, and Zone 12 barely provides it. That is why bulbs stay small or form a single round instead of splitting. Softneck varieties cope best, and some gardeners chill seed garlic in the fridge for a few weeks before planting to mimic winter.
Can I grow garlic in Zone 12 year-round?
No — not well. This is a cool-season crop, and outside the coolest months, roughly December through February, it bolts, turns bitter or fails to size up in tropical heat. Grow it in the cool window, and plant heat-loving crops in the hot months instead.
Can I plant garlic from the supermarket?
It is not the best choice: shop garlic may be treated to stop it sprouting, and it is often a variety that needs cold winters. Buy seed garlic from a garden supplier, and choose softneck varieties suited to warm climates.