Repotting guide

When & how to repot 'Purple Sprouting' Broccoli (Brassica oleracea var. italica 'Purple Sprouting')

Also called Purple sprouting broccoli, PSB.

More about 'purple sprouting' broccoli

About 'Purple Sprouting' Broccoli

Brassica oleracea var. italica 'Purple Sprouting' · also called Purple sprouting broccoli, PSB · edible

Purple sprouting broccoli is a hardy, overwintering brassica grown for masses of slender purple flower shoots in late winter and spring, rather than a single head. Sown in late spring, it stands through winter cold (which it needs to crop well) before bursting into productive spears. It demands firm, fertile soil, full sun, staking, and patience over its long 9-12 month season.

Mature size: 75-90 cm tall and up to 60 cm wide

Watch for — Wind-rock: Tall winter plants loosen in the soil during gales, tearing roots. Plant firmly, earth up the stems, and stake individually in exposed sites.

How to tell 'purple sprouting' broccoli needs repotting

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

Roots circling the bottom of the module or pot, or poking out of the drainage holes.
The seedling dries out within a day and growth has visibly stalled.
Roots are white and matted in a tight spiral when you tip the plant out.
It has outgrown its current container for the stage of the season — pot 'purple sprouting' broccoli on before it becomes hard root-bound.

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 'purple sprouting' broccoli

Pot on seedlings as they grow; not a perennial repot. 'Purple Sprouting' Broccoliis grown for one season, so the question is really “how often to pot on” — keep moving it up before the roots circle. Tall, robust, branching brassica that builds a large leafy framework through summer and autumn, then produces dozens of purple flowering side-shoots from the leaf axils in late winter and spring..

What size pot to step 'purple sprouting' broccoli up to

Pot 'purple sprouting' broccoli on gradually — a seedling jumped straight into a huge pot sits in cold, wet, airless soil and stalls. Step up one or two sizes at a time as the roots fill each container, finishing in a large final pot or the ground. The aim is roots that never circle and never check.

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 'purple sprouting' broccoli

Pot 'purple sprouting' broccoli on through the active growing season, whenever roots fill the current container — there is no single date, just "before it becomes root-bound". Avoid potting on during a cold snap.

Step-by-step: repotting 'purple sprouting' broccoli

Pot on before it is root-bound. Check 'purple sprouting' broccoli regularly; move it up as soon as roots reach the edge of the cell or pot, not after they have circled.
Step up one or two sizes. Choose the next container up — not a giant one. Cold, wet, unused soil around a small root system stalls seedlings.
Knock it out gently. Support the stem, tip the pot, and ease the rootball out without breaking it. A little teasing of circled roots at the base is fine.
Pot into rich mix. Set it into fresh rich, firm, well-drained loam, ph 6.5-7.5 at the same depth (tomatoes are the exception — they can go deeper to root along the stem).
Water in and grow on. Water well, keep it in good light, and resume feeding once it is established and growing again.

Aftercare

Water 'purple sprouting' broccoli in well and keep it in bright light; a freshly potted-on seedling can wilt for a day while roots settle, so do not overcompensate by drowning it. Do not fertilise for about 1 week — fresh mix already carries nutrients and feeding freshly disturbed roots scorches them.

The right soil mix for 'purple sprouting' broccoli

'Purple Sprouting' Broccoli wants rich, firm, well-drained loam, ph 6.5-7.5. Needs deep, fertile, moisture-retentive ground firmed hard before planting to anchor tall plants against winter wind. Enrich with compost or well-rotted manure and lime acidic soils to deter clubroot. Always use fresh mix when you repot — reusing old, broken-down soil reintroduces the compaction and poor drainage you are repotting to fix.

Repotting 'purple sprouting' broccoli — frequently asked questions

How often should you repot 'purple sprouting' broccoli?

Pot on seedlings as they grow; not a perennial repot for 'purple sprouting' broccoli. 'Purple Sprouting' Broccoli is a seasonal crop, so you pot it on as a growing plant rather than repotting a perennial. Step seedlings up gradually into rich, firm, well-drained loam, ph 6.5-7.5 so the roots never circle the cell, ending in a large final container. A root-bound transplant stalls and never fully recovers.

What size pot does 'purple sprouting' broccoli need?

When is the best time of year to repot 'purple sprouting' broccoli?

Can you put 'purple sprouting' broccoli straight into a much bigger pot?

No. Even a fast-growing 'purple sprouting' broccoli should only go up one pot size at a time. A vastly oversized pot holds a reservoir of wet soil the roots cannot reach, which stays cold and soggy and rots the roots — the opposite of what you wanted.

Should you fertilise 'purple sprouting' broccoli after repotting?

Not immediately. Wait about 1 week after repotting 'purple sprouting' broccoli. Fresh mix already contains nutrients, and feeding freshly cut or disturbed roots burns them. Resume your normal feeding routine once you see new growth.