When to Plant Garlic, by USDA Zone

Garlic is planted in fall and harvested the following summer, which makes it the longest-occupying crop in most home gardens and the one most often planted at the wrong time.

The rule behind the dates

Plant so that cloves have four to six weeks of soil above freezing to put out roots, but not enough warm weather to push significant top growth before winter. Roots anchor the clove and let it resume growth the moment the soil warms. Tall green shoots going into a hard freeze just get damaged.

A few inches of shoot before winter is normal, particularly in milder zones.

Planting windows by zone

Zone	Plant
3–4	Late September to early October
5–6	Throughout October
7	Late October into November
8	November
9	Late November into December

Treat these as starting points. Your first hard frost date is the better anchor: count back four to six weeks from it.

Hardneck or softneck

This is driven by your winter, and getting it wrong is the most common reason a garlic crop disappoints.

Hardneck (Allium sativum var. ophioscorodon) is the cold-hardy group, reliable in zones 3–6 and good through zone 7. It produces a central flower stalk — the scape — and one ring of large, easy-peeled cloves. It stores four to six months.

Softneck (var. sativum) performs better in zones 7–9, rarely produces scapes, and packs more, smaller cloves per bulb. It stores up to nine or ten months and is the type sold braided.

If you garden in zone 9 or warmer

Garlic needs vernalization: roughly four to eight weeks below 40°F to trigger the clove to divide into a bulb. Without it you get one large undivided round instead of a head of cloves.

Where winter will not deliver that, supply it yourself. Put seed garlic in a paper bag in the refrigerator for six to eight weeks before planting, then plant in late December or January. Choose softneck varieties, which need less chilling.

Getting it in the ground

Buy seed garlic from a garden supplier, not a supermarket bulb. Grocery garlic is often treated with a sprout inhibitor, and is usually a California-grown softneck poorly adapted to a cold-winter garden.

Break the head into cloves the day you plant, leaving the papery skin on each. Plant the largest cloves and cook the small ones — clove size directly determines bulb size at harvest.

Site in full sun with well-drained soil rich in organic matter, at pH 6.0–7.0. Set cloves pointy end up, 2 inches deep in mild zones and 3–4 inches in zones 3–5, spaced 6 inches apart with 12 inches between rows.

Once the ground has chilled, mulch with 4–6 inches of straw. Waiting matters: mulching warm soil keeps it warm and encourages exactly the top growth you are trying to avoid.

The following season

Pull mulch back from the shoots in early spring, and side-dress with a nitrogen source such as blood meal as growth resumes — garlic is a heavy feeder through spring.

On hardneck varieties, snap off the scapes when they curl, usually in June. This redirects energy into the bulb and gives you the best allium of the year for the kitchen.

Stop watering about two weeks before harvest. Lift bulbs when the lower three or four leaves have browned but five or six green ones remain — each green leaf is a wrapper layer, and you need those intact for storage.