5 Signals You Are Underwatering Plants

The signals a dry plant sends overlap with those of an overwatered one. Yellow leaves, wilting and poor growth can mean either, and the same bed can show both in one summer. Reading them correctly means checking the soil as well as the leaves.

Wilting with crisp leaves

A plant wilts when its cells lose the water pressure that holds them firm. Short of water, it closes the stomata, the small pores in its leaves, to cut evaporation, and the leaves soften and hang. On an underwatered plant they feel dry and papery and may curl or crisp at the edges. An overwatered plant wilts too, but its leaves feel soft and limp and the soil is wet. Many plants droop in strong afternoon heat and recover by evening, which is normal. A plant still wilted in the morning, after a cool night, needs attention. Containers show it fastest: a pot in full sun can dry out in a single hot afternoon, and a pot that feels light when lifted is usually a dry one.

Dry soil below the surface

The surface dries first and says little. Push a finger, a trowel or a long screwdriver into the ground. In moist soil a screwdriver slides in; in dry soil it resists, and the resistance grows as the soil dries. Sand gives way more easily than clay at the same moisture, so it pays to learn how each bed feels when wet and when dry.

Slower growth and smaller leaves

A short dry spell slows growth for a while. A long one shows in the new growth itself: smaller leaves, shorter stems, fewer flowers and fruit that stays small. Vegetables are the quickest to complain. Tomatoes short of water drop blossoms, and uneven watering, dry then soaked, is a common cause of cracked fruit.

Discolored lower leaves

The oldest leaves usually suffer first. They yellow, curl and develop dry brown edges, then drop. The damage climbs from the bottom of the plant because older leaves give up water and nutrients to the newer ones.

Footprints that stay on the lawn

Grass has its own signal. Walk across the lawn late in the day and look back. Blades with enough water spring back up; blades short of water stay flat, and the footprints remain. Clemson University’s Home and Garden Information Center adds two more lawn signs, a bluish-gray cast and blades that roll or fold, and suggests about half an inch of water on sandy soil or an inch on heavier soil, enough to wet the root zone 4 to 6 inches deep, applied early in the morning.

Telling thirst from too much water

No single sign decides it. Yellow leaves with dry, hard soil point to thirst. Yellow leaves with soggy soil and a sour smell point to too much water. Check the soil each time a plant looks wrong and change one thing at a time. For most garden plants, deep watering at longer intervals works better than a little every day, and it makes both kinds of stress less likely.