Currently my home state is in a drought, North and Central Texas in particular. Ranchers are reduced to slaughtering their animals because there is no water for them. (Seeing old timer farmers crying on the news because they're sick about having to kill their herds to spare the animal's suffering is enough to break your heart.) It's not been this bad since 1957 when Central and West Texas hit dust-bowl proportions. So I'm filled with GLEE when I see my neighbors running their sprinklers every single day. In the late afternoon. When it's windy. Because it is important to soak that concrete to help it grow and... that's not right. [/sarcasm] On average, 25% of the potable water in our country goes to LAWNS. Not our bodies, not our crops, our LAWNS. Much of that is lost to evaporation or run-off. The biggest waste of water is from applying too much too often. Excessive irrigation leaches the soil of nutrients, which then pollutes the ground water. And if there's excessive fertilizer on the lawn, that gets carried into the lakes and streams, and pollutes them, as well.
Have you ever seen a house with sickly, yellowing leaves on the shrubs? Or bright red leaves among the yellowing, sickly leaves? Number one indicator of over-watering. Which, by the way, is the number-one reason for plant death: over-watering.
Obviously I'm not going to be crazy and suggest that you don't have an emerald putting green at your home. That's crazy talk. Currently I live on a third of an acre with Bermuda grass. Last year I ran my sprinkler system four times. For the year. The whole year. In Texas. With triple digits in August. This year I've run my system once. My lawn is every bit as green as Right Angle's. How is that possible? Very easily. The key is to water long and deeply, and at the correct time of the day. And I have a xeriscape landscape. That usually conjures up images of gravel and yucca plants. Anyone that saw my gardening pictures the other day knows that isn't the case. Xeriscape means: good design based on your soil's condition, practical turf areas, appropriate plant selection - things that grow in your area, in other words, efficient irrigation, and use of mulches.
A xeriscape garden should decrease your maintenance by 50%.
The number one user of resources in a landscape is the lawn. You may not believe this, but grass needs more water than perennials, trees, shrubs, etc. How often do you mow? And now... how often do you deadhead your flowers? Having less lawn and more garden beds will decrease your need for maintenance, believe it or not. But not everyone wants gardens, so how do you know when to water? Should there be a schedule? The key is to LOOK at your lawn. Believe it or not, the grass will give clear indications that it needs to be watered. The blades will curl inwards, they'll begin to lose their luster, and when you walk on it, it may not spring back. THEN you need to apply one inch of water to the whole landscape.
So how do you do that? If you have a sprinkler system, it's very easy to determine how long your system needs to run to apply one inch. Use straight-sided cans (like cat food or tuna cans). Place them around the lawn and run your system. When the cans are 3/4 filled, mark the time your system ran, and there's your answer. However: if you have a sloped lawn, divide that time in half and run the system twice. You'll allow the water to be absorbed before it has a chance to run-off. This will also work with a manual sprinkler (the kind you played in as a kid).
So you've run your system (or drug the old back-and-forth sprinkler out), so when do you run it again? Every Saturday? Twice a week? It depends. Has your lawn began to show the signs of water need, as mentioned above? Or... have you stuck your finger in the ground to see if it's wet or dry? Easiest way to determine is to poke a finger in. If the top two knuckles on your pointer are moist when you've pulled it out, your lawn is fine.
The timing is important, as well. NEVER EVER RUN YOUR SPRINKLERS AT NIGHT. Not ever. NEVER. Wet plants + summer warmth = fungus among us. You've just created the best possible environment for all manners of baddies to thrive. NEVER EVER RUN YOUR SPRINKLERS DURING MID-DAY. OR IN THE WIND. OR WHEN IT IS RAINING. You laugh, but you know you've seen sprinklers running automatically during a rainstorm. Your sprinkler system should be on MANUAL. Here's an example:
My system (on manual) has nine stations. Based on my experiment with tuna cans, they all have a different time they run. It took me a day to set this up, but now I don't have to think about it. Nine systems, running on average 15 minutes a piece, and the whole system repeats once more. I have it set up to start at 4 am. It finishes around 7:30 am, just when the wind is starting to pick up - no sense in having the spray blown onto the sidewalk or street where it does my landscape no good. The absorption into the soil is almost complete by the time the sun really hits anything and causes evaporation, again, where it will do the landscape no good. The hotter it gets, I may set it to start at 3:30 am so it's finished before 7 am. The leaves will be dry throughout the day and not spend several hours in the cooler, damp conditions fungus and bugs prefer.
The idea in all of this is to get the water to move down through the soil to at least 6 inches. The problem with frequent and shallow watering is the roots grow horizontally, just under the surface, where they are more susceptible to drying out from hot winds, exposure from mowing too low, etc. The deeper the roots grow, the easier it is for your lawn to get its OWN water, thus reducing your need to apply water that you pay for. Bermuda, for example, will grow roots that are 18 inches long. One and a half feet. Incidentally, that's about how deep a TREE'S roots grow.
Here in Texas we have hard, clay soil that most people hate. The thing about clay is it holds water for a very long time. It's actually a benefit for us. Which is why I get away with not having to irrigate my gardens regularly. Those that have sandy, loose soil will obviously have to water more often. But as sandy soils tend to exist in areas of higher rain percentages... Not really - the need to add ADDITIONAL water isn't great. Again, stick your finger in. Top two knuckles dry? Time to water.
So here is my water waste rant. We are rapidly running out of potable drinking water in the world, and it's something so simple to fix, this one little aspect of our lives that uses a quarter of our entire supply of drinking water. I haven't even started on the fools that bag their clippings! Or excessive fertilizing! (Which causes excessive growth, which in turns forces you to mow more often, which makes more bags of clippings for our landfills, which...)
For the record, here's a list of common grasses in the US and their watering/ physical maintenance needs, one being the greatest need, ten being the least.
1. Tall fescue
4. centipede grass
5. seashore paspalum
6. St. Augustine
7. hybrid bermudagrass ("Tif" and "409" - used primarily on golf courses)
9. common bermuda
10. buffalo (requires NO additional irrigation - survives on rainfall only)
Last note: the more organic material you can incorporate into your landscape, the better water retention you'll gain. Applying a layer of compost to your landscape in the early spring when the lawn is beginning to green up, and again in fall when the lawn is beginning to decline and "sleep" for the winter is an excellent way to benefit your entire landscape. And LEAVE YOUR CLIPPINGS ON THE LAWN. Do not bag those clippings!!
*climbs off recycled material soap-box*
Thanks for listening, and the mojitos and nibblies are waiting everyone in the back yard.
*Statistics come from Texas A&M horticulture department, and the Texas Cooperative Extension, a division of TAMU.