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Entire healthy mature garlic plant in a real garden bed, showing growth habit and scale.Primary identification image. 45–60 cm tall, 10–10 cm wide at maturity.

Garlic

Allium sativum L.

Also called: Hardneck garlic, Softneck garlic

Family
Amaryllidaceae
Season
Cool-season perennial bulb grown as an annual
Best grown in
Portland, Oregon

Planted as cloves in autumn, garlic occupies its bed for eight to nine months and is harvested in early summer.

Safety: Toxic to dogs and cats.

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Life cycle & growth stages

  1. 1. ClovePlant cloves 5 cm deep, pointed end up, in autumn.
  2. 2. OverwinteringRoots establish; shoots emerge in late winter.
  3. 3. Spring growthLeaves lengthen; each leaf is a bulb wrapper.
  4. 4. ScapesHardnecks send up a curling flower stem; remove it.
  5. 5. BulbingBulbs swell as days lengthen.
  6. 6. Harvest readyLower leaves brown.
  7. 7. Harvest and cureLift, cure 3–4 weeks in an airy place.

Growth stages are ordered chronologically; timing varies with cultivar, temperature, light and care.

Planting calendar for Portland, Oregon

direct sow 2–6 weeks before last frost; 240–270 days to maturity from planting. Windows are derived from the region's average frost dates (last Apr 5, first Nov 5) and are estimates until you confirm your own dates in the calendar.

GarlicAllium sativum
PlantStart indoorsDirect sowAutumn sowTransplantTendHarvest
Garlic—Feb 22–Mar 22 (estimate)Sep 24–Oct 22 (estimate)—Mar 22–Oct 20 (estimate)Oct 20–Dec 31 (estimate)
  • Direct sow: Feb 22 – Mar 22
  • Tend and monitor: Mar 22 – Oct 20
  • Autumn sowing: Sep 24 – Oct 22
  • Harvest: Oct 20 – Dec 31

Spacing & support

In-row 10–15 cm; rows 30–30 cm. Planner footprint: 1 cell of 30 cm, 6 plants per cell.

Side-profile diagram of mature garlic: canopy 45–60 cm tall, 10–10 cm wide, shallow root zone, support and harvest-access envelope.

Soil & water

Soil
Fertile, well-drained loam
pH
6–7
Fertility
moderate
Water
Water in spring growth; stop 2–3 weeks before harvest.
Frost
very hardy; tolerates frost

Support & training

No support structure needed.

Garlic mid-season before harvest, showing branching, vining, rosette or upright habit and space occupied.

Harvest signs

  • Lower third of leaves brown, upper leaves green
  • Bulb wrappers intact when a test bulb is lifted
Garlic at harvest readiness, showing the visual cues: lower third of leaves brown, upper leaves green; bulb wrappers intact when a test bulb is lifted.

Common problems

Pests: onion fly, leek moth, nematodes

Diseases: white rot, rust

Appearance alone is not a diagnosis; confirm with a regional extension guide.

Side-by-side: healthy garlic leaf or fruit and an example of white rot.

Container growing

  • Minimum 10 L (20 cm deep)
  • Use quality potting mix and water more frequently
Mature garlic in a correctly sized container (10 L or more) with drainage visible.

Companion overview

4 reviewed relationship records (evidence: low).

Supported or conditional

None reviewed

Avoid or separate

None with evidence

Traditional claims only: Peas, Tomato.

2 popular pairings reviewed with no verified relationship.

Full companion profile

Crop rotation

Avoid planting garlic or other onion family crops in the same spot for 3 years. Rotation is about previous seasons, not about live neighbours.

Year 1Year 2Year 3AmaryllidaceaeOther familyOther familyback after 3+ years

Shared risks in Amaryllidaceae: onion white rot, downy mildew, onion fly.

Crop rotation hub

Sources, reviewer & update

Sources

Reviewer: Garden Planner editorial team (pending independent horticultural review)

Last reviewed: August 15, 2026 · version 1

Found an error or have feedback? Let us know.

Growing garlic

Garlic is planted from individual cloves in mid-autumn, 4–6 weeks before the ground freezes, so roots establish before winter; hardneck types need the cold. Spring planting is possible but gives smaller bulbs. Bulbs are harvested in early summer when the lower leaves brown.

Garlic planting material (crown, set, clove, slip or tuber) beside a ruler or coin for scale.
Garlic seedling at cotyledon and first-true-leaf stage, in soil, distinguishable from common weeds.
Garlic mid-season before harvest, showing branching, vining, rosette or upright habit and space occupied.

Because garlic is in the ground from autumn to summer, it overlaps with almost every other crop in planning terms: it occupies space that spring sowings cannot use until it is lifted, which is where relay planting comes in.

Two or more mature garlic plants with a tape measure showing in-row spacing (10–15 cm).
Garlic flower detail or bolting stage.
Immature bulb of garlic developing on the plant.

Hardneck scapes should be removed in late spring to put energy into bulbs. Rust, white rot and leek moth are the problems; rotate alliums on a three-year cycle and never replant in white-rot-infected soil.

Edible parts and safety

Edible: bulb (cloves), scapes, leaves. Toxic to dogs and cats.

Hands or tool harvesting garlic correctly (cut, pull, twist or pick) without damaging the plant.

Pests and diseases

Common pests: onion fly, leek moth, nematodes. Common diseases: white rot, rust. These vary by region; a photograph is an example, not a diagnosis. See the pest and disease guides and your local extension service.

onion fly on garlic, with a wider damage-context view.

Timeline

Season timeline for garlic: sowing, transplanting, flowering, harvest and bed occupancy aligned to frost dates.Text alternative: Direct sow Feb 22–Mar 22; Tend and monitor Mar 22–Oct 20; Autumn sowing Sep 24–Oct 22; Harvest Oct 20–Dec 31.

Related plants

See also: Amaryllidaceae family page · crop rotation · regional calendar · guides

Our Methodology & Sources

We synthesize peer-reviewed research, university extension publications, and trusted horticulture resources. Our evidence levels help you understand how strong the science is behind the guidance.

Evidence tiers

Supported evidenceConsistent results from multiple robust studies
Traditional claimHistorical use reported, limited scientific support
Context dependentMixed or variable results across conditions
No verified relationshipNo reliable evidence identified

Primary source types

  • Peer-reviewed journal articles
  • University extension publications
  • Government & research institute reports
  • Systematic reviews & meta-analyses

Last updated

August 24, 2026

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