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Our lawns and gardens have been struggling through some dry times lately, so lots of folks have been firing up those irrigation systems or dragging hoses to make up the difference.
Newly planted trees, shrubs and lawns and vegetable gardens need the most help. Well-established trees and shrubs will be just fine even if they do drop a few leaves. 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.
This schedule should continue through your new plant’s first hot summer of discontent. Watch the newest growth for slight wilting if you’re not sure how often to water. Short-term wilting won’t ruin the plant.
Since vegetables are at least 90 percent water, supplemental irrigation is a necessity to keep the vegetable garden happy. Consider some type of low-volume or “drip” system to avoid wetting the foliage of disease-susceptible plants like tomatoes, cucumbers and squash.
If you must water overhead, do so early in the morning to allow the foliage to dry before nightfall and avoid lots of loss to evaporation. Thorough wetting of the entire root area is the thing to do with vegetables.
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 a.m., 1 p.m. and 3 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 1-1.5 inches of water every five to seven 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 one-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.
Most folks use irrigation systems too often but don’t apply enough water each time. Even sandy soils near the beach shouldn’t need water every day. On heavier soils, you may be able to go an entire week without supplemental water. The thing to do is watch your plants. When they show slight signs of stress, it’s time to water.
If significant amounts of water begin to run off before you’ve added the necessary amount, program an extra irrigation cycle. Let’s say it takes 50 minutes to get the 1-1.5 inches of water on a zone. Set up the system to water for 25 minutes per zone then, after the last zone has finished, start another cycle of 25 minutes back at the beginning. This will give the applied water a chance to “soak in” and not run down to the storm drains.
If you have an automated irrigation system, consider adding a “rain check” device. These interrupt what’s been programmed into the controller when there has been adequate rainfall. While they haven’t received much of a workout so far this spring, a rain check is 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? These simple devices are available at any store that sells irrigation supplies.
Al Hight is the county extension director and horticulturist with the Brunswick County Cooperative Extension Service. Call 253-2610 or e-mail email@example.com.