How do I treat sunscald?

Treat the underlying cause of leaf loss, which is usually a foliar disease. Provide temporary shade cloth over exposed fruit during heatwaves.

Will sunscald spread to my other plants?

No. Sunscald does not spread from plant to plant — each affected plant developed it independently, usually from the same underlying conditions.

Sunscald

Q: What causes sunscald?

Sunscald is growing conditions. Sunscald is literally sunburn, and it happens when fruit or leaves that were shaded suddenly become exposed — usually because the plant lost foliage to disease or was pruned hard in hot weather. The damage is on the sun side, which is what separates it from every rot.

Mostly cosmetic

Growing conditions · does not spread · also called sunburn, leaf scorch

Sunscald is literally sunburn, and it happens when fruit or leaves that were shaded suddenly become exposed — usually because the plant lost foliage to disease or was pruned hard in hot weather. The damage is on the sun side, which is what separates it from every rot.

What it looks like

On fruit, a pale whitish or yellow patch on the shoulder facing the sun, which becomes papery, sunken and sometimes greyish as it dries. On leaves, bleached or brown patches on the most exposed surfaces rather than at the edges.

How to confirm it

Damage on the side facing the sun, not the blossom end or stem end.
Pale, papery and dry rather than soft or fuzzy.
Follows leaf loss or heavy pruning in hot weather.
On houseplants, follows a sudden move from indoors to full sun.

What to do

1Treat the underlying cause of leaf loss, which is usually a foliar disease.
2Provide temporary shade cloth over exposed fruit during heatwaves.
3Avoid heavy pruning of fruiting plants in midsummer.
4Acclimatise houseplants gradually when moving them outdoors.

What it gets confused with

One observation settles each of these.

Blossom end rot →

Blossom end rot is at the bottom of the fruit; sunscald is on the sunny shoulder.

Preventing it next time

Keep foliage healthy so fruit stays shaded.
Move plants to brighter positions in stages over a week or two.

Plants affected

Tomato Pepper Houseplants Hydrangea Maple & Shade Trees

Check these two things first

Push a finger into the soil, two knuckles deep. Wet soil plus a wilting plant means too much water, not too little — and it is the commonest reason a plant is dying. Dry soil plus crisp leaves means the opposite. The leaves look nearly identical either way, so the soil is what tells you.
Turn a damaged leaf over. Half of all diagnoses live on the underside: fuzz means downy mildew, fine webbing means spider mites, clusters of insects mean aphids. Nothing on the top of a leaf is as informative.

Most garden problems are cosmetic and resolve without treatment. Reach for a spray last, not first.

Not sure it is sunscald? Run the diagnostic key →