Articles by Jim Gainan

As published in the Billings Gazette

Maintain your landscape with a good watering program

Summer is here!  How do I know?  I have had to start watering my lawn and plants more often.  The combination of high temperatures, dry soils and winds rob the moisture from the plants and soil causing drought-stress.  Plants that become water-stressed are more susceptible to pests, disease and winterkill than healthy plants.


So, how much water is enough water?  Can I just let my sprinkler system run for 15 minutes three times a day and call that good?  That’s good enough for my trees and bushes, right?  Nope.


The importance of deep watering cannot be emphasized enough.  Deep watering encourages a well-developed root system that will be more tolerant of periods of drought.  Frequent, shallow watering encourages a shallow root system.  When roots stay near the surface of the soil, they are at a greater risk of drying out.  A good watering program is the best strategy for maintaining your landscape. 


Take a good look at your yard.  What type of soil do you have?  Soil with more clay absorbs water at a slower rate and will hold it longer, whereas sandy soil absorbs water more quickly and will dry out faster.  Take a walk across your lawn.  If your lawn is in drought-stress, the color of the grass will not be bright green, but a green tinged with blue or gray and your footprints will linger.


Look at the trees, shrubs and other plants in your yard.  Signs of under-watering may include wilted or curled leaves with crispy brown edges, especially towards the top and outer extremities, whereas plants that are over-watered may have older leaves that are yellow and wilted and new shoots may be pale green. 


Lawns require 1 inch of water a week, which is best applied all at one time.  In high heat, 10-15 minutes worth at a time evaporates before doing any good, whereas 1 inch gets below the surface and into the roots.  A moisture meter is a simple and inexpensive way to monitor the moisture in your soil and can be used for lawns, planters, hanging baskets and indoor plants.


To measure the water output of sprinklers, place small empty containers such as tuna cans at strategic spots in your yard.  After watering, measure the level and adjust watering times accordingly.  To prevent wasteful water runoff, do not apply water faster than the soil can absorb it. 



For trees and shrubs, Amy Grandpre of the Yellowstone County Extension office recommends applying 2-3” of water at a time on trees and shrubs.  If the trees and shrubs are young (less than 4 years), apply water inside the dripline of the tree near the trunk.  However, if the trees and shrubs are older, their root system is more extensive and watering from the edge of the dripline outwards is recommended.  A deep watering may last 2-3 months depending on soil conditions and species of the tree.  Aspen, birch, cottonwood, dogwood, maple, spruce and willow need more water than green ash, caragana, cotoneaster, lilac, pine and Russian olive. 


Hanging baskets and container gardens have their own special needs - consistent watering and fertilizing.  Plants in containers grow in a limited amount of soil and when we water as frequently as we need to, nutrients are leached from the soil.  Because the soil becomes nutritionally depleted, we need to replenish the nutrients by adding fertilizer.  Water when the soil is dry to the touch and thoroughly saturate the soil at each watering.  The water should run through the drainage holes in the bottom of the container.  This washes out any salts that have built up in the soil and you know that the soil is saturated.  When temperatures exceed 90 degrees, watering twice daily is a must.   


Watering in the cool of the early morning, just as the sun rises is best.  This reduces the amount of water lost to evaporation and ensures that the lawn and foliage of plants are dry before nightfall.  Wet foliage during the night encourages fungus in lawns, mildews, rusts and other diseases. 


Another strategy for maintaining soil moisture is to apply mulch.  In lawns, leaving grass clippings on the lawn during hot weather will help prevent evaporation and water runoff.  However, remove the clippings at the end of the hot weather to prevent disease.  Or, instead of grass clippings, Amy Grandpre recommends top-dressing the lawn with a thin layer (1/8” to ¼”) of compost.  This will also help prevent evaporation while adding organic matter to your lawn.  The MSU Extension Service Guide recommends keeping your mower set 2-3 inches high during warm weather.  Longer grass will help conserve water by keeping the soil cooler and minimizing evaporation.


There is no perfect watering schedule, but by being vigilant in monitoring soil moisture and observant as time passes and temperatures change, you and your yard will survive the summer heat.