Repotting guide

When & how to repot Red Romaine Lettuce (Lactuca sativa var. longifolia 'Rouge d'Hiver')

Also called Rouge d'Hiver lettuce, red winter lettuce, red romaine.

More about red romaine lettuce

About Red Romaine Lettuce

Lactuca sativa var. longifolia 'Rouge d'Hiver' · also called Rouge d'Hiver lettuce, red winter lettuce · edible

'Rouge d'Hiver' is a French heirloom red romaine with upright, bronze-red tinged leaves and crisp green hearts. It is unusually cold-hardy for a romaine, making it a reliable autumn, overwintered and early-spring crop. Cool weather and bright light deepen the red colouring; heat and long days fade the colour and push it to bolt and turn bitter.

Mature size: Heads 20-30 cm tall and 15-20 cm wide at maturity.

Watch for — Bolting in heat: Hot weather and long days send romaine to seed, turning leaves milky and bitter. Grow it in spring, autumn or overwintered, and choose shadier spots in summer.

How to tell red romaine lettuce needs repotting

Repotting on a calendar is less reliable than reading the plant. For red romaine lettuce, 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 red romaine lettuce 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 red romaine lettuce

Pot on seedlings as they grow; not a perennial repot. Red Romaine Lettuceis grown for one season, so the question is really “how often to pot on” — keep moving it up before the roots circle. Annual leafy crop forming an upright, elongated romaine head of self-folding leaves. Bolts into a tall flower stalk under heat and long summer days..

What size pot to step red romaine lettuce up to

Pot red romaine lettuce 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 red romaine lettuce

Pot red romaine lettuce 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 red romaine lettuce

Pot on before it is root-bound. Check red romaine lettuce 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 moisture-retentive, fertile, well-drained loam 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 red romaine lettuce 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 red romaine lettuce

Red Romaine Lettuce wants moisture-retentive, fertile, well-drained loam. Rich in organic matter with good water-holding capacity. Slightly acidic to neutral pH 6.0-7.0. A compost-enriched bed gives the steady nitrogen lettuce needs for tender, fast growth. Always use fresh mix when you repot — reusing old, broken-down soil reintroduces the compaction and poor drainage you are repotting to fix.

Repotting red romaine lettuce — frequently asked questions

How often should you repot red romaine lettuce?

Pot on seedlings as they grow; not a perennial repot for red romaine lettuce. Red Romaine Lettuce is a seasonal crop, so you pot it on as a growing plant rather than repotting a perennial. Step seedlings up gradually into moisture-retentive, fertile, well-drained loam 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 red romaine lettuce need?

When is the best time of year to repot red romaine lettuce?

Can you put red romaine lettuce straight into a much bigger pot?

No. Even a fast-growing red romaine lettuce 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 red romaine lettuce after repotting?

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