Troubleshooting Soil Crusting
In the exceptional heat of August, vegetable gardeners may sometimes find their soil in a precarious position. They may have supplied their plants with plenty of water, yet that water doesn’t seem to be infiltrating the ground. Instead, a thin, brick-like layer forms across the soil surface, preventing water from moving down into the root zone. It can also make it difficult for recently sown fall crops to emerge.
This phenomenon is known as soil crusting, and it is typically caused by repeated cycles of wetting and drying. As water is applied to the garden, soil aggregates gradually break down. Microscopic particles of silt and clay can then settle on the soil surface. After a summer of repeated watering and drying, those particles may become compacted enough that water has difficulty moving through the pores between them.
So, what is a gardener to do?
First, break up the crust.
While it may be tempting to reach for a motorized tiller, a little manual labor is the better approach. Using a garden hoe, hand cultivator or landscaping rake, lightly disturb the hardened soil surface. The goal is simply to break apart the crust and loosen the compacted particles without extensively disturbing the soil beneath it.
Gardeners should avoid using motorized tillers for this purpose. Tilling can further break down soil aggregates, making the soil more susceptible to crusting in the future. This is one reason no-till gardening focuses on disturbing only the soil where plants are placed rather than broadly tilling large areas. No-till practices also help preserve beneficial relationships between plant roots and soil fungi.
Once the crust has been addressed, gardeners can turn their attention to prevention.
Maintaining an adequate layer of mulch can help.
By late summer, the three-inch layer of straw mulch applied to many vegetable gardens in early spring may have thinned considerably. Erosion can move the straw, while decomposition gradually breaks it down.
As the mulch layer thins, it becomes less effective at maintaining even soil moisture and reducing soil drying. More drying means more soil aggregates can break down, increasing the potential for crusting. Re-examine your mulch in late summer and, if necessary, top it off with fresh straw.
Watering practices also matter.
As with ornamental plants, vegetable gardens benefit from slow, deep watering rather than quick, shallow applications. Heavy bursts of water can contribute to the breakdown of soil aggregates.
When possible, drip irrigation is an excellent option. It allows water to move slowly and deeply into the soil profile, delivering moisture where it is needed without disturbing the surrounding soil.
Gardeners experiencing persistent soil crusting may also benefit from having their soil tested. A soil test provides valuable information about soil pH and nutrient levels, while Johnson County K-State Extension's new pilot soil health testing program also measures soil nitrogen and organic matter. Made possible through a partnership with Johnson County Government Stormwater Management and Contain the Rain, the pilot is designed to help gardeners better understand their soil and make management decisions that improve long-term soil health.
Gardeners will do well to remember that soil crusting is an indicator that soil structure is struggling. Small adjustments to regular garden practices—such as reducing soil disturbance, maintaining mulch, and watering slowly and deeply—can ultimately make all the difference.
by Anthony Reardon, Horticulture Small Farms Agent, 2026