Garden MD
Practical answers for common garden problems

Diagnostic Guide

Why are my plant leaves curling?

Check the undersides of new growth for pests before assuming curling is a watering or heat problem.

Last reviewed: August 6, 2026 · Sources: University of California IPM, Penn State Extension

Quick Diagnosis

Start with the visible pattern

What you seeMost likely causeCheck first
Curling with visible insects underneathAphids or other sap-feeding pestsInspect undersides of new growth and stems
Curling with dry soil and hot weatherHeat or water stressCheck root-zone moisture depth
Curling with no pests and moist soilEnvironmental stress or a viral issue that needs monitoringCompare against nearby plants of the same type
Field Check

Inspect the undersides of curling leaves and the newest growth tips for clusters of small insects before treating for anything else.

Do This First

Simple checks before you buy anything

Most garden problems have more than one possible cause. Start with the simplest explanation.

  • Check soil moisture before treating for pests.
  • Inspect the undersides of curled leaves and stems for aphids or other insects.
  • Note whether curling is limited to new growth or spread across the whole plant.
Likely Causes

Most likely causes to check first

Aphids

Confidence: 55%

Aphids cluster on tender growth, distort leaves, and leave sticky residue that can lead to more trouble later.

  • Inspect the undersides of new leaves and stems.
  • Look for sticky honeydew or ants moving across the plant.
  • Check whether distorted growth is concentrated on soft new tissue.

Underwatering

Confidence: 48%

Underwatering leaves roots without enough moisture to keep foliage turgid, and it is often worse in containers, sandy soil, or hot, windy weather.

  • Check soil moisture several inches down, not just at the surface.
  • Note whether the plant recovers within a few hours of a deep watering.
  • Look for wilting that is worse in containers, sandy soil, or exposed, windy spots.
Sources

Reference material used on this page

University of California IPM

Powdery mildew identification and control

Publication date: 2025

Visit source

Penn State Extension

Watering, drainage, and root stress

Publication date: 2025

Visit source

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