Garlic
Allium sativum
A clove-by-clove pest ward — best kept clear of peas and beans.
- Type
- Vegetable · Grown as an annual
- Botanical family
- Allium (onion family)
- Foliage color
- Green
- Sunlight
- Full sun
- Watering
- Low
- Soil
- Rich, free-draining
- Feeding
- Bulbs & roots
- Frost tolerant
- Yes
- Season
- Cool Season
- Harvest type
- Single Harvest
- Start from
- bulb_tuber
- Germination temp
- 41–59°F
- Min soil temp
- 41 °F
- Photoperiod
- long day
- Sow direct
- 30 days before the last spring frost
- First harvest
- 120 days after the last spring frost
- Harvest ends
- 30 days before the first fall frost
- 240 d Harvest
- Plant spacing
- 4.7 in
- In-row spacing
- 3.9 in
- Between rows
- 11.8 in
- Square-foot density
- 9 per square
- Sow depth
- 1 in
- Root system
- A bulb with fine roots beneath it
- Working depth
- 4–10 in
- Can reach
- 16 in down where the soil allows
- Spread
- 3–6 in across, about 0.5–1× the width of the plant
- Shallowest pot
- 8 in of soil
Roots thread down from the base plate each season and are shed each season, and they go no further out than the leaves. Everything the bulb will store for next year is gathered in that narrow circle before the foliage yellows, which is why cutting the leaves early costs a flower.
The habit is Garlic’s own; the figures are what that habit usually comes to at this size, not a measurement of this species. Roots follow the soil either way: a compacted pan, a high water table or heavy clay stops them well short of any of it, and deep open ground lets them go further.
- Cats and dogs
- Recorded toxic
Recorded as toxic to cats and dogs by ASPCA.
- When
- Autumn-planted garlic is ready early-to-mid summer, roughly 8–9 months on; spring-planted a few weeks later. Hardneck types also give a scape (flower stalk) harvest 3–4 weeks before the bulbs lift.
- What to look for
- Lift when the lower third to half of the leaves have yellowed and browned but the top leaves are still green — each green leaf is an intact wrapper layer. Left too long, the bulbs split their skins and won't store; dig a test bulb to check the cloves are plump and well defined.
- How to harvest
- Loosen with a hand fork and lift by the base of the stem — never pull hard by the leaves, and never bruise the bulbs by knocking soil off against a boot. Snap off hardneck scapes when they curl once, cutting close to the top leaf; they're a crop in themselves.
- How often
- One main lift per season; scapes are picked once as they appear. Immature "green garlic" can be pulled from late spring for a milder, fresh-use crop.
- Storing the crop
- Cure whole plants for 2–4 weeks somewhere dry and airy until the wrappers are papery and the neck is fully dry, then trim roots and stems (or plait softnecks). Store at cool room temperature with air circulation; softnecks keep 6–9 months, hardnecks 3–5. Never refrigerate whole bulbs — it triggers sprouting.
- Onion fly & leek moth Maggots burrow into the base of onions, leeks, and garlic; leaves yellow and droop. Grow alliums under insect mesh and rotate to fresh ground each year.
- Thrips Minute slender insects that leave silvery flecking and distortion on leaves and flowers in hot, dry spells. Keep plants watered and use blue sticky traps under glass.
- Root & crown rot Roots or crown turn brown and mushy in waterlogged soil or compost; the plant wilts even when wet. Improve drainage, water less, and pot up only into free-draining mixes.
- Rust Orange-brown powdery pustules on leaf undersides, weakening the plant over the season. Remove affected leaves, avoid overhead watering, and clear all debris in autumn.
Beneficial predators that hunt this plant's pests — grow their favourite flowers nearby to recruit them. companion plant
- Beneficial nematodes Steinernema & Heterorhabditis spp.Hunts Onion fly & leek moth
Microscopic worms watered onto damp soil that hunt down soil-dwelling grubs and release a bacterium that kills them within days. Timing is the whole thing: warm, damp soil and a small target grub, which means late summer for most of what they are used against.
- Big-eyed bug Geocoris spp.Hunts Thrips
A stubby 3 mm bug with enormous wrap-around eyes, working the soil surface and the low foliage for aphids, mites, thrips and insect eggs. It is the main natural check on chinch bugs in a lawn and it is killed outright by insecticide.
- Damsel bug NabidaeHunts Thrips
A slender, mantis-armed bug that grabs aphids, small caterpillars, and thrips in low crops and meadowy edges. Leave a strip of unmown grasses and flowers for it to overwinter in.
- Green lacewing Chrysoperla carneaHunts Thrips
Its bristly larvae — "aphid lions" — impale aphids, mealybugs, thrips, and mite colonies, eating hundreds a week. Adults feed on nectar and pollen from small open flowers and overwinter in hollow stems left standing.
- Hoverfly SyrphidaeHunts Thrips
Bee-mimicking flies whose legless larvae graze aphid colonies clean while the adults pollinate. A ribbon of shallow, nectar-rich flowers kept in bloom all season recruits wave after wave of them.
- Minute pirate bug Orius spp.Hunts Thrips
A pinhead-sized true bug that is the best natural check on thrips, and happily spears aphids, mites, and insect eggs too. It needs pollen when prey is scarce, so keep something flowering nearby.
- Predatory mites Phytoseiulus & AmblyseiusHunts Thrips
Fast orange mites that hunt spider mites egg-by-egg, and cousins that clear thrips and fungus-gnat larvae. Sold as a biological control for greenhouses; outdoors they follow humidity — mist and mulch, don’t dust with sulfur.
- Rove beetle StaphylinidaeHunts Onion fly & leek moth
Slim, quick beetles with short wing cases that hunt in soil and litter, taking root-fly eggs and larvae, fungus-gnat larvae, and mites. Mulch and undisturbed ground keep them resident year-round.
Good neighbors
- Rose Repels pests
- Mizuna Repels pests
- Bok choy Repels pests
- Peach Repels pests
- Tatsoi Repels pests
- Raspberry Repels pests
- Apple Repels pests
- Plum Repels pests
Keep apart
- Green bean Garlic inhibits legume growth — keep beans away.
- Pea Garlic and onions stunt peas.
- Runner bean Garlic inhibits bean growth.
- Asparagus Alliums inhibit asparagus crowns.
- Fava bean Garlic inhibits legume growth; give broad beans an allium-free bed.
- Edamame Garlic inhibits legume growth; keep edamame apart.
Plant a single clove and it multiplies into a whole new bulb by midsummer.
Green-leaved vegetables, like this one.
The Cottage Garden Companion — the gardener's herbarium at cottagegardencompanion.com