Repotting guide

When & how to repot Allium 'Hair' (Allium vineale 'Hair')

Also called Hair allium, hair onion, curly hair allium.

More about allium 'hair'

About Allium 'Hair'

Allium vineale 'Hair' · also called Hair allium, hair onion · flowering

Allium 'Hair' is a quirky ornamental onion grown for green seed-head clusters that sprout wiry, twisting tendrils like tousled hair. Plant the small bulbs in autumn in full sun and free-draining soil. It flowers late spring to early summer at 45-60 cm tall, multiplies readily, and dries well for arrangements.

Mature size: 45-60 cm tall, spreading 10-15 cm per clump and multiplying over time

How to tell allium 'hair' needs repotting

Repotting on a calendar is less reliable than reading the plant. For allium 'hair', watch for these signs:

Roots growing out of the drainage holes, or the rootball lifting the plant proud of the rim.
Soil that has shrunk away from the pot sides and no longer holds water.
The pot is unstable because the plant has grown top-heavy.
Old, compacted, broken-down mix that stays wet too long — for a succulent that is a rot risk, so refresh it even if the pot size is fine.

For the underlying biology of a pot-bound root system and why it stalls a plant, see our guide to spotting and fixing a root-bound plant.

How often to repot allium 'hair'

Every 2–3 years, into bone-dry mix. Allium 'Hair''s growth habit — clump-forming bulbous perennial with strappy basal leaves and tall scapes topped by spherical umbels that develop wiry, curling tendrils instead of typical florets. — sets the pace. Allium 'Hair' is a quirky ornamental onion grown for green seed-head clusters that sprout wiry, twisting tendrils like tousled hair. Plant the small bulbs in autumn in full sun and free-draining soil. It flowers late spring to early summer at 45-60 cm tall, multiplies readily, and dries well for arrangements.

What size pot to step allium 'hair' up to

Use a pot only one size up — or even the same pot with fresh gritty mix if the roots have room. Allium 'Hair' stores water and rots in a large pot of slow-drying soil. A tight terracotta pot that dries fast is far safer than a generous plastic one. Never up-pot a succulent by several sizes.

Not sure of the exact diameter? Our pot size calculator takes the current pot and root spread and tells you the right next size — it deliberately recommends a single step up, never a big jump.

The best time of year to repot allium 'hair'

Spring or summer, while allium 'hair' is in active growth and warm, is best — roots recover fastest then, and the plant is not sitting in cool damp soil. Avoid repotting a succulent in winter dormancy.

Step-by-step: repotting allium 'hair'

Repot dry. Do not water allium 'hair' for several days first. Working with dry roots and dry mix dramatically lowers the rot risk for a succulent.
Pick a snug, fast-draining pot. Choose terracotta one size up at most, with a drainage hole. Have gritty sharply drained, sandy or gritty loam ready.
Tip it out and clean the roots. Slide the plant out, crumble off the old soil, and trim any black, mushy or dead roots with clean snips.
Pot into dry mix. Set allium 'hair' at its original depth in dry gritty mix, firming gently. Do not bury the stem deeper than it was.
Wait a week before watering. Leave it completely dry and out of harsh sun for about 7 days so any damaged roots callus. Only then water lightly.

Aftercare

Keep allium 'hair' completely dry and out of fierce sun for about a week so any nicked roots callus before they meet moisture; watering a freshly repotted succulent is the classic way to rot it. Then resume the normal lean, dry rhythm. Do not fertilise for about 3 weeks — fresh mix already carries nutrients and feeding freshly disturbed roots scorches them.

The right soil mix for allium 'hair'

Allium 'Hair' wants sharply drained, sandy or gritty loam. Tolerates poor, dry soils. Sharp drainage is essential to prevent bulb rot; add grit to heavy clay or grow in raised beds. Neutral to slightly alkaline pH suits it best. Always use fresh mix when you repot — reusing old, broken-down soil reintroduces the compaction and poor drainage you are repotting to fix.

Repotting allium 'hair' — frequently asked questions

How often should you repot allium 'hair'?

Every 2–3 years, into bone-dry mix for allium 'hair'. Repot allium 'hair' every 2–3 years into a snug pot of sharply drained, sandy or gritty loam, ideally in spring or summer. Let it sit in dry soil and do not water for about a week afterwards so any nicked roots can callus. Over-potting and watering straight away is what rots succulents.

What size pot does allium 'hair' need?

When is the best time of year to repot allium 'hair'?

Should you water allium 'hair' after repotting?

No — not straight away. Repot allium 'hair' into dry mix and wait about a week before the first watering so any damaged roots callus over. Watering a freshly repotted succulent is the single most common way to rot one.

Should you fertilise allium 'hair' after repotting?

Not immediately. Wait about 3 weeks after repotting allium 'hair'. Fresh mix already contains nutrients, and feeding freshly cut or disturbed roots burns them. Resume your normal feeding routine once you see new growth.