Monday, May 7, 2012

Keith Mickler column: Watering the landscape properly

Watering the landscape properly


By Keith Mickler, County Coordinator


It's time for all us gardeners to take a very close look at our current landscape irrigation practices and make sure that the water we apply is being used to the fullest by the plants.  I am fearful that we are headed down the road to another record breaking drought all across Georgia. Knowing how to apply water in the correct amount is critical.


Example of what not to do: set the automatic irrigation control timer to come on every Monday, Wednesday and Friday. What happens if it has rained an inch?


Listen, I can be a genuine smarty pants when I see people doing stupid things such as wasting water by running their irrigation when it's raining or after we have had a big rain. My biggest pet peeve is the setting of irrigation controllers to come on with no regards to rainfall and/or amount of water being applied. Most people haven't the foggiest idea of how much water their irrigation system is applying. I can go on for hours on this subject; just say "No Wasted Flow."

When all you can tell me is that your irrigation systems runs for 30 minutes for each zone, you are telling me nada, zilch, nothing. But what I did glean from you is that you have no idea how much water you are applying? What if it's not enough or too much!!!


The amount of time the irrigation system runs means nothing, unless there is an association between that and the amount of water applied.  I have seen systems that could supply the required amount of water within 30 minutes, while others take over two hours.

The amount of water that is applied by your irrigation system is determined by pipe size, pressure and the number and type of sprinkler heads used. Since no irrigation zones are the same, each zone should be calibrated to determine the exact amount of water that is being applied.  The amount of water that is applied during each watering is more important than frequency.


Established lawns and landscapes don't need and shouldn't be watered daily. Deep, infrequent watering is better than frequent watering. Established lawns and landscapes should be given one inch of water per week. This one inch should be applied by each zone and in one irrigation cycle, say like on Monday morning. However, if it's very hot and dry and stuff looks wilted and/or gray you may need to water again providing another inch later on in the week, say like Friday morning.


One inch of water doesn't sound like a lot, but it is. One inch applied over an acre is 27,200 gallons of water. Now that's a lot of H20. So, let's take the average quarter of an acre lot as an example: there would be approximately 7,000 square feet remaining in turf and landscape plantings once the house is finished and driveways/sidewalks poured. That 7,0000 square feet will require over four thousand gallons of water to apply one inch of water to the turf and landscaped area.


How to Calibrate that Irrigation System

To figure out how much water your irrigation system is applying, use the following method. Place 10 or so straight sided cans at random throughout the zone area to be irrigated turn on that zone for a set amount of time (say 1 hour, 30 minutes if you choose); after the irrigation has stopped stick a ruler into each can to check the depth of water. Next we add all the depths up and get the total amount of water applied and then divide by the number of cans used and wham, you have how much water (in inches) your irrigation system applied during the time it ran. Remember to do this for each irrigation zone on your system.


Most who complete this relatively simple test are shocked by the results. In many cases it's determined that only a portion of the water needed is being applied. Sometimes we learn that our irrigation system is applying excessive amounts of water which is wasted. So, do what is environmentally responsible just say "No Wasted Flow."

  • Water only once a week, twice a week if very hot and dry and plants/turf are wilting.
  • Soak don't sprinkle. When you water, aim the nozzle at the base of plants so more water will reach the roots.
  • Don't water in the heat of the day. You will only lose water to evaporation. If you have an automatic system, set it to come on in the early morning hours between 4 a.m. and 10 a.m.
  • Turn off the sprinkler when it rains. Install a rain sensor shut-off switch.
  • Mulch! Using pine straw, bark chips or hardwood mulch around the roots of plants and trees helps the soil retain water.

Keith Mickler is the County Coordinator and agriculture agent for The University of Georgia/Floyd County Cooperative Extension. Located at 12 East 4th Ave, Rome, GA 30161 (706) 295-6210. Office hours are Monday-Friday 8:00 a.m. - 5:00 p.m. The University of Georgia Cooperative Extension - Learning for Life. Agriculture and Natural Resources, Family and Consumer Sciences, 4-H Youth.  An Equal Opportunity/Affirmative Action Institution. To obtain extension publications please visit our web site or contact your county Cooperative Extension office.


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