Repotting guide

When & how to repot English Walnut 'Howard' (Juglans regia 'Howard')

Also called Howard walnut.

More about english walnut 'howard'

About English Walnut 'Howard'

Juglans regia 'Howard' · also called Howard walnut · edible

'Howard' is a late-leafing English walnut prized in California for large, smooth, light kernels and reliable cropping. It leafs out late to dodge spring frost and blight, needs a long warm summer to fill nuts, and is typically grown on Paradox rootstock. Lateral-bearing, it yields heavily on a moderate-vigour, spreading tree.

Mature size: 9-15 m tall and 9-12 m wide in an orchard; can reach 18 m unpruned. Bears within 4-7 years of grafting.

Watch for — Crown and root rot: Phytophthora in wet or poorly drained soil kills the lower trunk; plant high on well-drained ground and keep irrigation off the crown.

How to tell english walnut 'howard' needs repotting

Repotting on a calendar is less reliable than reading the plant. For english walnut 'howard', 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 english walnut 'howard' 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 english walnut 'howard'

Pot on seedlings as they grow; not a perennial repot. English Walnut 'Howard'is grown for one season, so the question is really “how often to pot on” — keep moving it up before the roots circle. Vigorous, single-trunked deciduous tree with a rounded, spreading crown. 'Howard' is a productive lateral-bearer, fruiting along the shoots as well as at terminals, giving heavy mid-to-late-season yields..

What size pot to step english walnut 'howard' up to

Pot english walnut 'howard' 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 english walnut 'howard'

Pot english walnut 'howard' 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 english walnut 'howard'

Pot on before it is root-bound. Check english walnut 'howard' 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 deep, 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 english walnut 'howard' 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 english walnut 'howard'

English Walnut 'Howard' wants deep, well-drained loam. Demands deep (1.5-2 m+), free-draining fertile loam with pH 6.0-7.5. Will not tolerate waterlogging or heavy clay hardpan; shallow or poorly drained soils cause crown rot and shorten tree life. Always use fresh mix when you repot — reusing old, broken-down soil reintroduces the compaction and poor drainage you are repotting to fix.

Repotting english walnut 'howard' — frequently asked questions

How often should you repot english walnut 'howard'?

Pot on seedlings as they grow; not a perennial repot for english walnut 'howard'. English Walnut 'Howard' is a seasonal crop, so you pot it on as a growing plant rather than repotting a perennial. Step seedlings up gradually into deep, 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 english walnut 'howard' need?

When is the best time of year to repot english walnut 'howard'?

Can you put english walnut 'howard' straight into a much bigger pot?

No. Even a fast-growing english walnut 'howard' 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 english walnut 'howard' after repotting?

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