While occasional yellow leaves may be part of a plant’s natural growth cycle, widespread yellowing should prompt a closer look at watering habits, drainage, and soil health, and any necessary adjustments.
Overwatering and underwatering
One of the most common plant care mistakes is also one of the easiest to overlook: improper watering. Because both too much and too little water can make plants look unhealthy, many people struggle to tell the difference. The leaves often provide a hint.
“When most plants are under-watered, they wilt, and the leaves either fold, or tilt downward, or both, and when they do, the edges of the leaves remain relatively straight,” Rohner said.
These leaves are wilting and curling, indicating the plant is underwatered.
Agriscaping
Overwatered plants tend to behave differently. “When you over-water, or the plant does not have enough soil drainage, the roots begin to rot, and the leaves shrivel or ‘pucker,’ and the edges of the leaves typically curl or get wavy rather than wilt,” he said.
Another early warning sign can appear before root rot develops: the leaves will often turn more yellow, starting at the outer edge. If you’re unsure which issue you’re dealing with, check the soil before reaching for the watering can. If the soil is consistently soggy, reduce watering and improve drainage; if it is dry, water the plant more thoroughly.
Plants that are overwatered and suffering root rot have a wavy look.
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Pests, disease and environmental stress
Insects, fungal diseases, and environmental conditions can all affect plant health. Fortunately, these problems often leave distinct signs behind.
“When looking at the leaves, pest and disease issues typically show up as either pitting, holes, or irregular patterns of color on the leaves themselves,” Rohner said.