Repotting guide

When & how to repot Mustard Spinach 'Savanna' (Brassica rapa var. perviridis 'Savanna')

Also called Savanna mustard spinach, komatsuna cultivar.

More about mustard spinach 'savanna'

About Mustard Spinach 'Savanna'

Brassica rapa var. perviridis 'Savanna' · also called Savanna mustard spinach, komatsuna cultivar · edible

'Savanna' is a vigorous komatsuna (mustard spinach), a fast, leafy Asian green with smooth, glossy dark-green leaves on crisp stems. It tastes milder than mustard and richer than spinach, stands both heat and cold better than true spinach, and is slow to bolt. Crop it as baby leaf in weeks or grow on to full bunches.

Mature size: 25-40 cm tall and 20-30 cm wide; harvest baby leaf at 10 cm.

How to tell mustard spinach 'savanna' needs repotting

Repotting on a calendar is less reliable than reading the plant. For mustard spinach 'savanna', 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 mustard spinach 'savanna' 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 mustard spinach 'savanna'

Pot on seedlings as they grow; not a perennial repot. Mustard Spinach 'Savanna'is grown for one season, so the question is really “how often to pot on” — keep moving it up before the roots circle. Upright, loose rosette of broad, smooth oval leaves on slender pale stems; one of the quickest-growing leafy brassicas..

What size pot to step mustard spinach 'savanna' up to

Pot mustard spinach 'savanna' 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 mustard spinach 'savanna'

Pot mustard spinach 'savanna' 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 mustard spinach 'savanna'

Pot on before it is root-bound. Check mustard spinach 'savanna' 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 fertile, moisture-retentive loam, ph 6.0-7.5 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 mustard spinach 'savanna' 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 mustard spinach 'savanna'

Mustard Spinach 'Savanna' wants fertile, moisture-retentive loam, ph 6.0-7.5. Rich in organic matter with free drainage. Dig in compost before sowing; abundant nitrogen drives the tender, fast leaf this crop is grown for. Always use fresh mix when you repot — reusing old, broken-down soil reintroduces the compaction and poor drainage you are repotting to fix.

Repotting mustard spinach 'savanna' — frequently asked questions

How often should you repot mustard spinach 'savanna'?

Pot on seedlings as they grow; not a perennial repot for mustard spinach 'savanna'. Mustard Spinach 'Savanna' is a seasonal crop, so you pot it on as a growing plant rather than repotting a perennial. Step seedlings up gradually into fertile, moisture-retentive loam, ph 6.0-7.5 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 mustard spinach 'savanna' need?

When is the best time of year to repot mustard spinach 'savanna'?

Can you put mustard spinach 'savanna' straight into a much bigger pot?

No. Even a fast-growing mustard spinach 'savanna' 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 mustard spinach 'savanna' after repotting?

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