Fresh water is one commodity that we all need to conserve. And, as we work our way toward the summer months, irrigation for the lawn and landscape becomes more of a concern.
Before you start dragging hoses or fire up that automated irrigation system, keep a few things in mind.
Newly-planted trees, shrubs and lawns and vegetable gardens will need the most help during hot and dry periods. Well-established trees and shrubs should be able to make it through a “normal” summer – however you define “normal” – without a lot of irrigation help. Just remember to water thoroughly and deeply each time and wait for slight signs of stress to time your next watering.
The most common reason that new trees and shrubs fail in the landscape is not getting adequate water. That doesn’t mean you should leave the water on 24/7 and float the poor tree out of the ground, but thorough waterings several times a week are in order as it becomes established. Watch the newest growth for slight wilting if you’re not sure how often to water. Short-term wilting won’t ruin the plant.
If you’re trying to manage a newly-sodded lawn, things are a bit different. Immediately after laying the sod, water lightly several times during the warmest part of the day. For instance, you might set up your irrigation system to water at 11:00 a.m., 1:00 p.m. and 3:00 p.m. to help the rootless grass stay hydrated. Since you don’t have a significant root system yet, deep watering is a waste. You just want to keep the top two inches or so moist. Follow that schedule during the first week after laying the new sod. As the grass “tacks down” or begins to root, reduce the number of waterings but add more time to each so that the soil is wetted more deeply. After three weeks or so you can go back to infrequent, thorough waterings based on visible signs of stress from the grass.
You often hear rules-of-thumb that suggest adding 1 to 1 ½ inches of water every 5 to 7 rainless days. Rules-of-thumb are inherently flawed but sometimes it’s all we have. One question we get a lot is, “How long does it take to apply 1 inch of water?” The definitive answer is, “It depends.” It depends on your water supply and the type of equipment you are using. The solution is a tuna can. Place empty tuna cans around the area and run the irrigation. Since the height of a tuna can is about 1 inch, the time it takes to fill the can will tell you how long you need to run the system.
If you have an automated irrigation system, consider adding a “rain check” device that will interrupt what’s been programmed into the controller when there has been adequate rainfall. These simple devices are great for saving water when you’re away. Wouldn’t it be great if we didn’t have to see irrigation systems running in the middle of a summer deluge? Rain checks are available at any store that sells irrigation supplies.