Saving Water Can Help Your Lawn and Landscape

Even though watering restrictions are not yet commonplace
throughout Alabama, homeowners should still take measures to conserve water. I have seen more plants killed by overwatering
than under-watering. Overwatering does more than deplete the water supply and our bank account; it also makes plants more prone to pests, more drought sensitive and adds to our collective stormwater runoff problem. Stormwater runoff pollutes our streams and
lakes by moving fertilizers, soil and chemicals into the waterways.

By choosing and operating a watering system correctly, you can reduce water bills, insect and disease problems, make grass or shrubs more drought tolerant and reduce maintenance requirements. To maintain a healthy lawn in sandy soils may require as much as 2" of water per week during peak growing season but in most soils 1” per week is sufficient. The more you
water your lawn, the faster it grows and the more it needs to be mowed. Warm season grasses are generally very drought tolerant and will simply go dormant during a drought if the roots are trained to grow deep. You train deep roots by watering infrequently but deeply after initial establishment. Many irrigation systems are set to run three times or more per week and those lawns lose a lot of water to evaporation and encourage shallow root development. Many
homeowners feel compelled to run the irrigation even if the lawn does not need the water because they feel it justifies the initial expense of the system. However, we should think of the
irrigation system as insurance or maybe like a vitamin. Our body needs vitamins but we can get too much of a good thing and cause other problems. We also like insurance but mostly we like having the peace of mind it gives us and we are not anxious to use it -especially life insurance.

What’s true for turf is even more true for established trees and shrubs which may require less than half as much water as an established turf. In most years we get enough rainfall for well-established trees and shrubs and they do not need regular irrigation. If you have thirsty plants like hydrangeas, azaleas or dogwoods low volume drip or micro-sprinklers are a much more efficient way to water than solid set sprinkler systems.

To save water don’t rely too heavily on these thirsty landscape plants but choose mostly water efficient and drought tolerant plants, including tough heirloom shrubs, trees and the sturdier native plants. If you group plants according to their water needs (called a hydrozone), you can simplify watering methods and systems. For example, turf areas and shrub areas should always be separated into different hydrozones. They do not need the same amount or frequency of water. Enclose trees and shrubs into large mulched beds rather than small rings or worse no
rings surrounded by turf. For turf areas, install a rain shutoff device or soil moisture sensor (if you have an automatic sprinkler system) that will override the system when it rains or when the soil reaches a preset moisture level. Your county’s Extension office, the Natural Resources Conservation Service or a certified irrigation professional can provide technical assistance. Except for the first couple years of establishment time you do not need permanent irrigation for most shrub and tree beds. Flowers and thirsty shrubs are the exception and should be watered on an as needed basis rather than on a regular schedule like turf.

Water turf in the early morning from 4:00 am to 7 am. This is the most efficient time because
temperature and wind speeds are usually at their lowest, this in turn reduces evaporation and, more importantly, off target drift. Also, grasses are less susceptible to fungal problems if water is applied at the time that dew normally forms. Avoid watering between 10 a.m. and 4 p.m. temperature and wind speeds are at their highest during this time so water waste is more likely. Do not continue to water during the winter months.In most years you can turn the system off and drain it in November and leave it off till late spring. An exception would be the year of establishment.

Lastly, calibrate your sprinkler system regularly. Make sure it is putting out water evenly over
the entire area. Also, look for broken or leaky sprinkler heads. Sometimes what you think is a leaky sprinkler head is really low head drainage. If you are on a slope water will run to the
lowest head and drain from the pipe. You can stop this problem by installing heads with built in check valves or by adding check valves under existing sprinkler heads.

There are many ways to save water and reduce stormwater runoff. Visit the Alabama Cooperative
Extension System website and look at the Alabama Smart Yards Handbook for more good tips. http://www.aces.edu/pubs/docs/A/ANR-1359/ANR-1359.pdf

Rain gardens offer a low tech solution for excess rain water

Question: The rain barrel I installed this summer seems very small in view of the large quantities of rain we have gotten. What other strategies can I use to reduce the water runoff from my property?

Answer: Rain barrels or cisterns have their place in water management, but as you have seen they are totally inadequate alone to deal with large amounts of rainfall. There are several ways to deal with excess rain, but clearly the way we do it now in urban areas does not work very well. We have large areas of impervious surfaces and we direct water into storm water systems that often become overwhelmed. What if every home, apartment complex, business or neighborhood could capture the first inch or so of rainfall in any rain event? I believe this could be done and would go a long way towards reducing storm water and associated non-point source pollution problems.

Rain gardens are an old idea whose time has come again. Let’s face facts. We in the southeast live in a climate where we always have and always will have a feast or famine of rainfall. Even those with a short term memory can recall the severe drought of 2007. However, those of us with better memories and a few years behind us knew the day would come when flooding would be a problem again. Rain gardens offer a low tech and low cost way of slowing down water, letting it infiltrate rather than contribute to the storm water problem and reducing the amount of non-point pollution that enters our streams and rivers.

Simply speaking a rain garden is a depression or swale in the landscape designed to capture and retain runoff for short periods of time. If designed properly rain gardens should drain in three days or less and provide a way to direct overflow in periods of continual rainfall such as we have recently experienced in much of the southeast. Rain gardens can and should be a landscape asset both in terms of function and beauty. Ideally they should be located several feet away from the home to avoid contributing to water related problems in the basement or foundation. Water that currently runs off the house, walks, parking areas and driveways should be diverted to these depressions to slowly soak into the ground.

Do not think of a rain garden as a pond that does not hold water very well. Think of it as a true garden in every sense of the word. It is not a landscape feature but a critical component of the functionality and beauty of the landscape. Choose plants that can tolerate both occasional flooding and fairly extreme drought. Fortunately, we have many southeast natives that fit the bill very well because many of them have had a feast or famine relationship with water for a very long time. Because of this long standing weather pattern many native plants have become adapted to these environmental conditions. However, not all native plants will thrive in these conditions so you must do a little research before choosing your plants. Native plants fill niches within our environment so look for those plants that naturally grow in the light and soil conditions you have or will create within a rain garden. Do not forget about the many tried and true non-native plants that also grow well under these conditions.

Many books are available to help you make the right plant choices but for a more comprehensive look at this topic I strongly recommend Rain Gardening in the South, by Helen Kraus and Anne Spafford. As the name implies this book focuses on strategies as well as plants that work for southern conditions. The plant lists are great even though there are many plants that would work that are not included and a plant or two I would avoid that are included, such as Japanese Flowering Apricot. However, the information on design is well worth the modest cost of this book. Even though rain gardens are low tech they are not simple given that they are a small ecosystem unto themselves. Therefore, careful attention to design is important to make certain it functions as intended. For instance, you do not want to build a mosquito haven and this must be addressed early to avoid costly “do over’s”.

Fall is an excellent time to build a rain garden and an even better time to establish trees, shrubs and many perennials that may be used. It won’t rain forever, so start working on your plans and when it dries out get your shovel and go to work. Don’t forget to call before you dig to avoid costly and potentially dangerous encounters with underground utilities. For help locating buried utilities contact “Alabama One Call”. For further information on building your own rain garden visit the Alabama Cooperative Extension System web site and type in rain garden in the search box at the top.

Image by North Carolina State University

Drip Irrigation

Question: I want to install a landscape at my new home but am very worried about the water shortage. What tips can you give to increase my chance of success?

Answer: The first suggestion would be to plant as soon as possible. In our area we can plant woody plants all winter if the ground is not frozen. The plant roots will start to grow and establish before the plant top growth occurs and before the stress of a hot summer.

Second, I would encourage you to consider using a low volume irrigation system. Low volume irrigation unlike sprinklers puts the water in a small area near the plant. Sprinklers are very wasteful because they water the entire surface area and much of the water either runs off or evaporates. Low volume methods work by placing emitters in a flexible tube near the base of newly planted trees and shrubs. (picture at right is from the University of Texas publication on "Low Volume Irrigation")

The primary design goal of a low volume system is to apply water to a uniform soil depth. Water is delivered at or below the surface of the planted area exactly where it is needed. For new landscapes the emitter should be placed directly over the edge of the root ball of the newly installed plants. This will keep the root ball moist while encouraging new roots to develop in the native soil. For larger plants you may need two or more emitters to insure the root ball maintains adequate moisture.

These systems are not difficult to install and remind me of playing with tinker toys as a kid. The most critical part of installation is making sure you reduce the pressure before the water enters the drip tubes and provide a screen filter in-line to avoid stopping up the small holes in the emitters. It is very important to periodically check the emitters to make sure they do not get stopped up. Unlike sprinklers which are highly visible you can’t really tell if emitters are working unless you inspect them while they are operating.

I have often been asked why can’t I just punch or drill a small hole in a water line near the plant rather than buying emitters. The answer is simple. These small holes would not distribute the water evenly, the water would come out too fast, and the hole would get larger over time. Emitters are designed to put out very slowly at rates from ½ to up to 2 gallons per hour. If your soil is a very heavy clay soil you would want a very low rate emitter and if it is sandy you could use the higher rates. If you use a high rate emitter on a heavy or hard soil the water will pool on the surface and run off the target area.

I know many municipalities tell their customers to do hand watering only during times of water shortages but low volume drip irrigation is even more water conserving then hand watering. Generally speaking when people do hand watering on new plants they water a larger area than necessary, water is applied too quickly causing runoff, and some water evaporates before reaching the ground. Also, who’s going to know if the water is on if it is below the surface. I am not encouraging wasteful use of water but I believe this is even more water conserving than hand watering and I would not feel the least bit guilty for using this method in lieu of hand watering. Just make sure you are using a timer so that the system only runs a prescribed amount of time. I made the mistake of leaving mine running without a timer several years ago and floated my plants out of the ground after a couple days. To learn more you may watch a short training video for gardeners at Texas Earth Kind web site and choose the "Low Volume Irrigation" tab.