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Allium fistulosum
Growing calendar
Typical timing for central Japan (Kanto region). Shift it for your own climate, and record your actual dates.
Guides
- How to Grow Welsh Onions from Seed: Sowing, Germination and Transplant Size
- Planting Welsh Onions: Trench Depth, Spacing and Rooting a Supermarket Bunch
- Earthing Up Welsh Onions: How to Grow a Long White Shank
- Welsh Onion Problems: Thrips, Rust, Leaf Miner and Rot at the Base
- Harvesting Welsh Onions: Cut and Come Again Instead of Pulling
- Welsh Onion Year Round Care: Dividing, Cutting and Overwintering a Clump
Common problems
Start from what you can see on the plant.
Pests and diseases (43)
Problems recorded for this plant, most serious first.
Rust
MajorDisease
Small raised orange-yellow to red-brown pustules form on both leaf surfaces, then rupture and release powdery spores. Heavy infection yellows the leaves and kills them early.
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.
Leek Moth
MajorPest
White grazed scars and small holes line the leaf surface, and splitting the leaf reveals larvae inside. Damaged leaves snap easily and die back.
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.
Root-lesion Nematode
OccasionalPest
Elongated blackish brown necrotic lesions form on the root surface and fine roots rot away. Above ground the stand is uneven and plants stay small with pale foliage.
Leafminer Flies
OccasionalPest
Winding white tunnels run through the leaf with the larva at the head of the mine. Heavy mining turns the whole leaf white and dead, cutting photosynthesis.
Fusarium Yellows
Disease
Yellowing starts on the lower leaves, the petioles twist and the plant leans to one side. Vascular tissue browns, growth stops, and heading vegetables may die without ever forming a head.
Fusarium Wilt
Disease
Lower leaves wilt during the day and recover morning and evening, and this cycle repeats as the plant dies back. Cutting the stem reveals characteristic browning of the vascular tissue.
Late Blight
Disease
Dark green water-soaked lesions appear on the leaves and expand quickly into brown dead tissue. White mold forms on the underside and at the lesion edge, and dark brown lesions spread to stems and fruit.
Southern Blight
Disease
The stem rots at soil level and white silky mycelium spreads over the crown and the surrounding soil surface. Brown sclerotia the size of rapeseed then form and the plant wilts and dies rapidly.
Anthracnose
Disease
Light brown to dark brown round lesions with sharp margins form on leaves and fruit, slightly sunken in the center. In wet weather salmon-pink slimy spore masses ooze out on the lesions.
Damping-off
Disease
The stem pinches in at soil level, turning water-soaked to brown and thin, and the seedling topples over. Infection before emergence makes the stand uneven with missing plants.
Bacterial Soft Rot
Disease
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.
Root Rot
Disease
Fine roots rot brown to blackish brown, growth stops and the lower leaves yellow. The plant wilts easily in the daytime and eventually dies outright.
Root-knot Nematode
Pest
The plant wilts in the daytime and does not recover with feeding or watering. Pull it up and the roots carry beaded chains of galls of varying size with few fine roots.
Bacterial Spot
Disease
Small water-soaked spots appear on the leaves, later turning brown with yellowing around them. Fruit develops water-soaked or scabby spots from which rot spreads.
Downy Mildew
Disease
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.
