How to Grow Onion: Growing Guide to Planting, Care & Harvest

Allium cepa

Growing calendar

Typical timing for central Japan (Kanto region). Shift it for your own climate, and record your actual dates.

JanFebMarAprMayJunJulAugSepOctNovDec

Sow / plantHarvest

Guides

Common problems

Start from what you can see on the plant.

Wilting Yellow leaves Leaves dying White powder Leaf spots Pests Fruit problems Poor growth

Pests and diseases (42)

Problems recorded for this plant, most serious first.

Onion Thrips

MajorPest

Fine white stippled scars run in vertical lines along the leaf surface, and the whole leaf eventually turns whitish. Growth stops and both yield and quality suffer.

Thrips

CommonPest

Silvery white to brown scarring spreads over leaf and fruit surfaces. Flowers discolor and drop, and fruit is left with keloid-like scar tissue.

Seedcorn Maggot

CommonPest

Emergence is uneven, and digging up seed reveals white maggots inside the seed or hypocotyl. In transplants the stem base rots and the plant wilts.

Bolting

CommonDisorder

A flower stalk rises from the center of the plant and the leaves turn tough and stringy, spoiling eating quality. Heading vegetables run to seed without ever forming a head.

Bacterial Soft Rot

CommonDisease

The crown or the head becomes water-soaked and soft, then collapses into a slimy mush. The rotting tissue gives off a distinctive foul odor.

Onion Yellow Dwarf

CommonDisease

Yellow streaks appear along the leaves, which twist and lodge easily. The whole plant is stunted and the bulb and leaf sheaths bulk up very poorly.

Leek Moth

CommonPest

White grazed scars and small holes line the leaf surface, and splitting the leaf reveals larvae inside. Damaged leaves snap easily and die back.

Downy Mildew

CommonDisease

Pale yellow to yellow-brown angular lesions form on the upper leaf surface with a gray-purple mold in the matching spot underneath. Lesions merge, the leaves die back and the plant declines early.

Fusarium Yellows Late Blight Bacterial Canker Sclerotinia Rot Rust Southern Blight Anthracnose Damping-off Root-knot Nematode Gray Mold Bacterial SpotNecrotic StreakBacterial Scale RotBotrytis BlightDry RotSmall Sclerotial RotBotrytis Leaf BlightPlant-parasitic NematodesBotrytis Neck RotWhite TipCalcium DeficiencyFusarium Wilt and Damping-offPink RootBacterial RotStem NematodeSclerotial RotMycelial Neck RotStunt DiseaseLeaf BlightBlack MoldAlternaria Black SpotBlack Dot Leaf BlightSmutWhite Rot

Written byYasuGrowing vegetables and fruit in Chiba, Japan, and building Gadenin. Corrections are welcome. 15 years of growing.