Vegetable · Root & Bulb
Garlic
Allium sativum
A slow-growing, cold-hardy allium usually planted from individual cloves in fall for a summer harvest. Needs a long season and a period of cold to form well-divided bulbs.
At a glance
Edible parts: Bulb
Family: Allium
Includes onion, garlic, leek, and chives. Known for pungent, sulphur-rich compounds that give the group its characteristic smell and flavour.
Harvest
Dig bulbs once the lower third to half of the leaves have browned; cure in a shady, dry, well-ventilated spot for 4-6 weeks before storing.
Growing conditions
- Temperature
- 30–80 °F
- Soil pH
- 6–7
- Soil type
- Deep, well-drained, loose soil high in organic matter; avoid heavy clay
- Climate
- Very cold-hardy; the cloves themselves need a period of cold to form well-divided bulbs.
- Growing season
- Plant cloves in fall, 4-6 weeks before the ground freezes, for a harvest the following summer; spring planting is possible in mild-winter climates but usually gives smaller bulbs.
- Nitrogen
- Medium (≈30–60 ppm)
- Humidity
- Medium (≈40–70 %)
- Planting unit
- Seed
- Feeding schedule
- Side-dress with a nitrogen-rich feed in early spring while foliage is developing; stop fertilizing with nitrogen after late spring so energy shifts to bulb formation instead of leaves.
- Pest resistance
- High - generally trouble-free, occasional onion thrips
- Pests
- Onion thrips: Tiny, slender insects that rasp at leaf surfaces, leaving silvery streaks and patches, favoring alliums.
- Pruning
- Cut off curling scapes on hardneck varieties once they appear, to redirect energy into the bulb.
Notes
Cloves need roughly 4-8 weeks of cold below 40°F (vernalization) to trigger the single clove to divide into a full, segmented bulb - without it, bulbs stay small and undivided. Fall planting lets winter provide this naturally; in warm-winter climates, cloves can be pre-chilled in a refrigerator before spring planting.
Where it grows
- In-Ground GardenIdeal— Usually planted in fall for a summer harvest the following year.
- Raised BedIdeal
- Container / PotPossible— Needs a deep pot (10in+) and protection from extreme freezes for fall-planted cloves.
- HydroponicNot recommended— Bulb formation doesn't suit standard hydroponic systems.
- Vertical / TrellisNot recommended— No climbing or vining habit.
- WindowsillNot recommended— Needs a cold period and more light than a windowsill offers to form good bulbs.
Companions & antagonists
- Antagonistic: Green Bean — Mutual entry for the allium/legume interference - see green bean's companion notes.
Sources
- Growing Garlic in the Home Garden — Rutgers New Jersey Agricultural Experiment Station
- Growing Garlic in a Home Garden — University of Maryland Extension
- How to Vernalize Garlic for Success in Warmer Growing Zones — Grow Organic