Repotting guide

When & how to repot Long Spider Orchid (Brassia longissima)

Also called Long Spider Orchid, Arching Brassia.

More about long spider orchid

About Long Spider Orchid

Brassia longissima · also called Long Spider Orchid, Arching Brassia · tropical

Brassia longissima is a hot-to-intermediate growing epiphytic orchid from Colombia and Ecuador prized for extraordinarily long, spidery orange and reddish-brown mottled flowers. It thrives in bright filtered light, high humidity, and well-draining bark mix. Water generously during active growth and reduce in winter to trigger blooming.

Mature size: 30–45 cm (12–18 in) tall; flower spikes to 60 cm (24 in) bearing up to 10 blooms each reaching 15 cm (6 in) across

Watch for — Shrivelled pseudobulbs: Caused by insufficient humidity or underwatering. Move the plant to a more humid spot, add a pebble tray, and check watering frequency. Once pseudobulbs are firm again, the plant recovers fully.

How to tell long spider orchid needs repotting

Repotting on a calendar is less reliable than reading the plant. For long spider orchid, watch for these signs:

The bark medium has broken down into a dark, soggy, soil-like mush that no longer drains.
Roots are climbing out of the pot in all directions (this is normal for long spider orchid and not on its own a reason to repot).
Roots inside the pot are brown, soft and rotting rather than firm and green/silver.
It is about two years since the last repot, or you can smell sour, decomposing bark — repot just after flowering finishes.

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 long spider orchid

Every 1–2 years, when the bark breaks down. Long Spider Orchid's growth habit — sympodial epiphyte with compressed, bifoliate pseudobulbs producing arching flower spikes from the base — sets the pace. Brassia longissima is a hot-to-intermediate growing epiphytic orchid from Colombia and Ecuador prized for extraordinarily long, spidery orange and reddish-brown mottled flowers. It thrives in bright filtered light, high humidity, and well-draining bark mix. Water generously during active growth and reduce in winter to trigger blooming.

What size pot to step long spider orchid up to

Keep long spider orchid in the same size pot, or go up just one, only if the roots have genuinely outgrown it. Orchids flower better slightly snug, and a big pot of bark stays wet and rots the roots. The reason you are repotting is the broken-down bark, not a need for more space — a clear pot lets you watch the roots.

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 long spider orchid

Repot long spider orchid immediately after the flowers have finished, just as new roots or a new growth start to emerge — those fresh roots establish quickly in new bark. Never repot an orchid in full bloom; you will drop the flowers and shock the plant.

Step-by-step: repotting long spider orchid

Repot after flowering. Wait until long spider orchid has finished blooming and is pushing new roots. Soak the pot first so the roots are pliable and less likely to snap.
Remove all the old bark. Slide the plant out and crumble away every scrap of broken-down bark — that soggy mush is the actual problem you are fixing.
Trim dead roots. Cut off any brown, hollow or mushy roots with sterilised snips. Keep all the firm green/silver ones.
Repot into fresh bark. Settle long spider orchid into the same or one-size-up pot of fresh coarse coarse bark-based orchid mix, working bark between the roots so there are no big air gaps.
Hold off watering briefly. Mist or wait a few days before the first proper water so any cut roots seal. Then resume the normal soak-and-drain rhythm.

Aftercare

Give long spider orchid a few days before its first proper watering so cut roots seal, then return to the weekly soak-and-drain. Keep it bright, humid and out of direct sun while new roots grip the fresh bark. It may pause growth briefly; that is expected. Do not fertilise for about 3 weeks — fresh mix already carries nutrients and feeding freshly disturbed roots scorches them.

The right soil mix for long spider orchid

Long Spider Orchid wants coarse bark-based orchid mix. Use a fast-draining medium of medium-grade fir bark, perlite, and charcoal in roughly 3:1:1 ratio. Good air circulation around roots is essential. Repot every two years as bark breaks down and becomes water-retentive. Always use fresh mix when you repot — reusing old, broken-down soil reintroduces the compaction and poor drainage you are repotting to fix.

Repotting long spider orchid — frequently asked questions

How often should you repot long spider orchid?

Every 1–2 years, when the bark breaks down for long spider orchid. Repot long spider orchid every 1–2 years — but because the bark medium has broken down and gone soggy, not because it has outgrown the pot. Do it just after flowering, into the same size or one up, using fresh coarse bark-based orchid mix. Old, decomposed bark suffocating the roots is the real problem.

What size pot does long spider orchid need?

When is the best time of year to repot long spider orchid?

Why does long spider orchid get repotted if it isn't outgrowing the pot?

Because the bark medium breaks down. Over 1–2 years the chunky bark rots into a dense, soggy, soil-like mush that suffocates the roots — that, not size, is why you repot long spider orchid. Refresh it into fresh coarse bark just after flowering.

Should you fertilise long spider orchid after repotting?

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