Smart Techniques Conserve Water in Your Yard

Many parts of Nebraska received good amounts of rain so far this year, greatly reducing drought conditions across the state. But conditions in July have quickly turned hot and dry; resulting in some lawns and landscape plants needing irrigation.     Using good irrigation or watering techniques is a basic skill for keeping plants healthy and conserving water. But many gardeners, especially those with in-ground irrigation systems, water too frequently and apply too little water at each irrigation. No matter what plant you’re watering – lawns, perennials, shrubs, trees – watering deeply encourages a deeper and more extensive root system resulting in healthier plants.  With that in mind, check out these landscape watering techniques for both homeowners with in-ground irrigation systems and those using sprinklers and hoses.   Deep and Infrequent
Water plants deeply, but infrequently, when irrigation is needed. Avoid frequent, light applications of water, such as 10-15 minutes 2 to 3 times per week. This often results in a shallow layer of continually wet soil, which prevents oxygen movement into the soil. Plant roots need oxygen to survive, and without it they will eventually begin to die. This type of watering is particularly harmful to woody plants.   What does “deep” mean? Try to keep soil moist about ½ inch deeper than the deepest roots. Generally, this means moistening the soil about 6-inches deep for turf, 8 to 12-inches for ornamentals and vegetables, and 12 to 24-inches for trees and shrubs.   What does “infrequent” mean? It depends on air temperature and your soil type. Clay soil holds more water and stays moist longer, while sandy soil holds less water and will require more frequent irrigation.  During cool periods with no rain, infrequent watering may mean one deep irrigation per month on clay soil. During hot periods, it may mean 2 to 4 deep irrigations per month. It all depends on how quickly the soil dries out and the root depth of the plants being irrigated.   Use the screwdriver method below to determine your current soil moisture, then decide if conditions have gotten dry enough to warrant irrigation. For turf, 1) watch for a color change from bright blue green to a duller green as plants get drier, or 2) wilting of leaf blades or foot prints left in turf after it is walked on. These signs indicate the turf needs irrigation.   Screwdriver Technique
A long-bladed screwdriver or other metal probe can be used to assess current soil moisture or how determine how deeply irrigation has moistened the soil.    To assess current soil moisture, push the screwdriver into the ground. The probe should move easily through moist soil. It may even come out wet or muddy when moisture is very high.     If it’s difficult to push the screwdriver into the soil, moisture is low and your plants may need irrigation. With time and practice, you’ll develop a feel for your soil and the resistance level which indicates watering is needed.    After irrigation, probe the soil until you reach a layer of greater resistance. Remove the probe and measure the depth of soil moistened.   Soak and Cycle Technique How do you get irrigation water to go deep and not waste water to runoff? Try the soak and cycle technique.   Cycle through your zones once using a run time short enough to stop irrigation before water starts to run off the landscape. Then cycle through the zones a second time in the same day to push the water down deeper. The soak and cycle technique is particularly helpful when 1) soil compaction is high and water infiltration slow, 2) in heavy clay soil and 3) on slopes where water tends to run off.    Manual Irrigation The ultimate goal is not running in-ground irrigation systems on a preset schedule, but assessing soil moisture and only watering when necessary. Turn the system on manually, run through the zones and utilize the soak and cycle technique if necessary to encourage deep water penetration into the soil. Then turn the system off and don't water again until the screwdriver technique indicates water is needed.  A beautiful lawn can be managed with less frequent irrigations and possibly save you some money, too. Your plants, both turf and trees, will thank you for changing to a deep and infrequent watering schedule.     Images

1. A long-bladed screwdriver or other metal probe can be used to assess current soil moisture or how determine how deeply irrigation has moistened the soil. Image from John Fech, Nebraska Extension. 
2. Footprints left in turf after grass has been walked on indicate moisture stress. Image by Aaron Patton, Purdue University Turfgrass Extension Specialist.