plant

Welsh onion

Allium fistulosum

Updated 8 Jul 2026 · AI-parsed entry

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

What it needs & gives back

↓ Needs

Sunlightfull sun to partial shade
Watermedium

↑ Gives back

Biomassmedium

Companions

Through the year

Emergence

Emergence of new shoots in early spring after the last frost and when soil temperatures reach 50C.

Flowering

Flowering occurs in late spring to early summer, typically 3 months after emergence, as day length increases.

Fruiting

Fruiting follows flowering, with seeds maturing over 45 days.

Harvest

Leaves can be harvested continuously from 60 days after emergence throughout the growing season.

Dormancy

Plants enter dormancy with the first autumn frost or when air temperatures consistently drop below -50C.

Timing is relative to your local season (temperate Northern Hemisphere).

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