Check soil moisture during summer heat waves

Recent weather conditions have been very hot and dry in much of Central Kansas and we are seeing environmental stress take a toll on many plants.  Now is a good time to evaluate the soil conditions around important plants in the landscape and irrigate if necessary to prevent further stress.

Environmental stress or even dormancy on cool season turf during summer heat and drought is common in Central Kansas


Remember that lawns are usually not the first priority for water in a landscape, but here are some things to consider. The type of turfgrass you are growing will greatly determine the kind of moisture that is required to allow it to survive the summer heat and stress. Cool season turf such as tall fescue requires more water than bermudagrass or buffalograss to make it through extended hot, dry conditions. The important thing is to keep the crown of the turf grass plants alive so that regrowth can occur in cooler fall weather.

Many lawns in the area are showing some signs of dormancy. Normally, a healthy lawn can become dormant for a few weeks and still recover. But it is important to at least keep the crown of the turf grass plants hydrated because if the crown dies, the plant dies.  Lawns can vary greatly in their ability to survive a period of dormancy due to how they have been managed in the past, but in general in is a good idea to apply about 1/4-1/2 inch of water every two weeks to hydrate the crown of the plants as long as they are alive. If you are wondering if the turf is still alive, pull up an individual plant and separate the leaves from the crown. The crown is the area between the leaves and the roots. If it is still hard and not papery and dry, the plant is still alive.

Other plants

Concentrate watering efforts on the most important plants in the landscape such as shade trees, shrubs or plants that cannot be replaced easily. It can take many years to grow a tree, while a lawn can be replaced much more quickly.

When planning to irrigate, take into consideration the soil in which the plant is growing, Soil has a profound effect on how well your plants can handle drought periods. Typically, our home landscape soil in the city is neither deep nor rich unless it has been amended. Often it is a thin and shallow soil that tends to dry quickly. Plants growing in such soil may show stress symptoms such as leaf wilting or leaf scorching during the growing season. 

Check the soil by probing it with a rod or long flat-head screwdriver. It will be easy to shove the screwdriver to an 8 to 12-inch depth if soil moisture is adequate.  If the screwdriver is difficult to push in and there is resistance, watering is likely needed.   Remember the look of the soil surface can be deceiving, so actually checking is always best.

Water slowly

It is best to deliver water slowly to ensure the water soaks into the soil without running off and being wasted.   An ordinary garden hose set at a slow trickle can work well.  Using a soaker hose or sprinkler can also work.  If you see surface runoff soon after you start, stop and let the water soak in and then continue to apply water in intervals that avoid runoff until the soil is moistened.   It is best to water to a depth of between 8 and 12 inches for most woody plants. Use the screwdriver to probe the soil and verify that it slides in easily to that depth after watering. 

After watering also take time to refresh or replace mulch around plants if needed to reduce the evaporation of water from the soil during the rest of the season.