Most of Wyoming has been blessed this spring with abundant moisture. It’s times like these that water worries go away, but drought can hit this state any time — in fact 60 percent of the time we are in drought. Water, not oil, is the life blood for gardeners, ranchers and farmers alike and it’s foolish to not use water for irrigation as efficiently as possible.
First things first: Most people apply 40 inches of water over their entire landscape every year — that’s more than a yard of water every year over every square inch. In our communities, that’s a lot of drinking water given to lawns to quench their thirst. So the trick is to reduce the amount of water by at least 20 percent and still get a great landscape.
I’ve mentioned numerous times that life below ground exists in the first twelve inches. That is certainly true for lawn grasses, trees, flowers and veggies. It doesn’t make sense, then, to under water or water too deep; but just to 12 inches. As you go deeper into the soil profile there is less and less oxygen — less oxygen means fewer roots. Roots need oxygen as much as they need water to grow and produce. Hence, deep root watering is a myth — the roots aren’t deep but shallow because they need oxygen.
A common practice among gardeners is to irrigate every other day. Throw that practice out the window. There is no place on earth that nature provides plants with only fifteen minutes of water every other day and you shouldn’t either — besides this practice is terribly inefficient. Most of the water never gets 12 inches into the soil. Instead, the water sits near the surface being easily evaporated under our western breezes, intense sun and low humidity. You are throwing money and a precious resource away.
Whether you drag a hose across your landscape as I do to irrigate or have a sophisticated irrigation system — both need to be calibrated to water to a depth of 12 inches. The great thing is, it’s simple to do.
As crazy as this sounds, allow your lawn to go into drought stress — don’t water. By drought stress, I mean when you walk across your lawn the grass blades don’t spring back. It’s time to irrigate. Only this time, I want you to irrigate for only 15 minutes. Afterwards, cut out a plug of soil and measure with a ruler how far the water penetrated the soil. If it only went two inches, go back and irrigate for another 15 minutes. Check again how far the water penetrated the soil. Keep doing this until you get to twelve inches — record that time. Every yard will be different — the front yard will be different from the backyard as will the side yards. Now, when you irrigate, you will always irrigate for that recorded time — that time will never change.
What does change throughout the growing season will be the frequency of irrigations. Common sense tells you that sandy soils will dry out faster than clay soils, which hold moisture for longer periods of time. So if you have sandy soils, the frequency between irrigations will be higher than those with clay soils. I grow on sandy soil and my irrigation frequency is once every seven days this time of year and once every five days in the heat of summer. For those of you with clay soils, the time between irrigations will be longer.
Frequency of irrigations is as much as art as it is science. You will need to keep an eye on your plants, they will tell you when to irrigate. If you follow this method, you will reduce at least 20 percent from your water bill and have a much healthier and happier landscape.