How do I treat underwatering?

Water thoroughly until it runs from the drainage hole. If the compost has dried into a solid block that repels water, stand the pot in a basin for half an hour to rewet it.

Will underwatering spread to my other plants?

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

Underwatering

Q: What causes underwatering?

Underwatering is growing conditions. The distinction between too much and too little water is the single most useful thing a plant owner can learn, because the above-ground symptoms are nearly identical and the treatments are opposites. The soil, not the leaves, gives you the answer.

Treatable

Growing conditions · does not spread · also called drought stress

The distinction between too much and too little water is the single most useful thing a plant owner can learn, because the above-ground symptoms are nearly identical and the treatments are opposites. The soil, not the leaves, gives you the answer.

What it looks like

Drooping leaves that feel dry and papery, crisp brown edges and tips, and soil that has shrunk away from the sides of the pot. The whole plant looks deflated, and lower leaves go crisp and yellow before dropping.

How to confirm it

Leaves dry and crisp rather than soft and limp.
Soil dry and often pulled away from the edge of the pot.
A pot that feels noticeably light when lifted.
Recovery within a few hours of a thorough soak — which also confirms the diagnosis.

What to do

1Water thoroughly until it runs from the drainage hole.
2If the compost has dried into a solid block that repels water, stand the pot in a basin for half an hour to rewet it.
3Trim off crisp dead leaves — they will not recover.
4Move out of direct heat and wind while it recovers.

What it gets confused with

One observation settles each of these.

Overwatering →

Feel the soil first. Wet soil plus wilting is overwatering; dry soil plus wilting is thirst.

Fusarium wilt →

A thirsty plant recovers after a soak. A wilt-diseased plant does not.

Preventing it next time

Check soil moisture by touch rather than on a schedule.
Mulch outdoor beds and containers to slow evaporation.
Move to a slightly larger pot if a plant dries out within a day or two.

Plants affected

Most garden and container plants can be affected.

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 underwatering? Run the diagnostic key →