Repotting guide

When & how to repot Rutabaga 'American Purple Top' (Brassica napus var. napobrassica 'American Purple Top')

Also called American Purple Top rutabaga, purple top swede.

More about rutabaga 'american purple top'

About Rutabaga 'American Purple Top'

Brassica napus var. napobrassica 'American Purple Top' · also called American Purple Top rutabaga, purple top swede · edible

'American Purple Top' is a classic heirloom rutabaga with large, round roots, bright purple shoulders, and sweet yellow flesh that mellows after frost. A dependable storage variety, it is sown in mid to late summer for autumn and winter use over a 90-110 day season, and rewards fertile, evenly moist, well-drained soil with smooth, heavy roots.

Mature size: Foliage 30-45 cm tall; roots typically 10-15 cm across, around 0.5-1.5 kg at maturity.

Watch for — Clubroot: Brassica root disease producing galled, swollen roots and stunted plants. Practise 3-4 year rotation, improve drainage, and lime toward neutral pH to reduce infection.

How to tell rutabaga 'american purple top' needs repotting

Repotting on a calendar is less reliable than reading the plant. For rutabaga 'american purple top', 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 rutabaga 'american purple top' 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 rutabaga 'american purple top'

Pot on seedlings as they grow; not a perennial repot. Rutabaga 'American Purple Top'is grown for one season, so the question is really “how often to pot on” — keep moving it up before the roots circle. Biennial brassica grown as an annual; a crown of blue-green foliage above a large, rounded root that sits partly proud of the soil. Flowers in a second year if left in ground..

What size pot to step rutabaga 'american purple top' up to

Pot rutabaga 'american purple top' 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 rutabaga 'american purple top'

Pot rutabaga 'american purple top' 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 rutabaga 'american purple top'

Pot on before it is root-bound. Check rutabaga 'american purple top' 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, well-drained loam, ph 6.0-6.8 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 rutabaga 'american purple top' 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 rutabaga 'american purple top'

Rutabaga 'American Purple Top' wants fertile, well-drained loam, ph 6.0-6.8. Prefers firm, fertile, moisture-retentive yet free-draining soil rich in organic matter. Loosen compacted ground so roots swell evenly, and watch boron levels — deficiency causes brown-heart in the flesh. Always use fresh mix when you repot — reusing old, broken-down soil reintroduces the compaction and poor drainage you are repotting to fix.

Repotting rutabaga 'american purple top' — frequently asked questions

How often should you repot rutabaga 'american purple top'?

Pot on seedlings as they grow; not a perennial repot for rutabaga 'american purple top'. Rutabaga 'American Purple Top' is a seasonal crop, so you pot it on as a growing plant rather than repotting a perennial. Step seedlings up gradually into fertile, well-drained loam, ph 6.0-6.8 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 rutabaga 'american purple top' need?

When is the best time of year to repot rutabaga 'american purple top'?

Can you put rutabaga 'american purple top' straight into a much bigger pot?

No. Even a fast-growing rutabaga 'american purple top' 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 rutabaga 'american purple top' after repotting?

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