plant

Welsh onion

Allium fistulosum

Updated 4 Aug 2026 · AI-parsed entry

Welsh onion (Allium fistulosum) — a plant, for Full sun, Medium water. Companions: Tomato, Cabbage.

What it needs & gives back

↓ Needs

Lightfull sun to partial shade
Watermedium

↑ Gives back

Mulch_biomassmedium

Companions

Through the year

Through the year

JFMAMJJASOND
emergenceEmergence of new shoots in early spring after the last frost and when soil temperatures reach 5°C.
floweringFlowering occurs in late spring to early summer, typically 3 months after emergence, as day length increases.
fruitingFruiting follows flowering, with seeds maturing over 45 days.
harvestLeaves can be harvested continuously from 60 days after emergence throughout the growing season.
dormancyPlants enter dormancy with the first autumn frost or when air temperatures consistently drop below -5°C.

Soil interactions

Drainagewell-drained
Nitrogen fixingNo
MycorrhizalNo
Accumulatessulfur
Soil textureloam, sandy loam
Organic matterMedium
Compaction toleranceLow

Propagation

Methodsseed, division
Difficulty2 / 5
Establishes in~1 yr
Stratificationnone
Self-seedingModerate
Divisionspring

Wildlife & pests

Repelsaphids, carrot rust fly, slugs
Can host diseasesonion white rot, downy mildew, rust