Tuesday, May 26, 2009

Lawns, Landscaping and Water in Southeast Texas

Here in The Woodlands Texas and all over Southeast Texas, this is the way many people think - you have to have put a lot of water on your landscape to have a pretty yard. We almost have to in order to have the lawns and the beauty we want. But let's add, NOT! The beauty? We need beauty in our lives. Nope, the beauty is not the issue here; the high volume of water is! We all have had our bad experiences with drought and seen what happens when we deprive our landscapes of water - more than just brown lawns - dirt yards even!

Our reaction to dead grass or plants is natural. We conclude that did not water enough! In most cases that is an incorrect conclusion. Our lawns are susceptible to various diseases and must be treated for those specific diseases when contaminated; this is typically the source of browning and yellowing. It can also be due to nutrition issues. We can starve our landscapes from water, but many of us do just the opposite. Water can be expensive to many of us and some of us just do not want that expense. Some of us have also experienced what happens when we forget the sprinkler and leave the water running all night. We get our water bill and ask, "who left the water on? or "what is leaking?", or maybe chastise ourselves for not having an automatic cutoff device attached to our hose. Maybe we need to recheck our thinking on how we use our water outside. In this second of a two part series on water conservation, we will explore this outdoor subject. What say the experts?

First and foremost, the experts say we need to water outside only once per week to have a beautiful lawn. Some sources will tell us that St Augustine needs watering every 5 days. The Woodlands Joint Power Agency says twice a week. I am of the opinion that we do need to water deeply and as infrequently as we can. That may translate to twice a week in July, August and September. Depending on what species of St Augustine grass is in our lawn, it will more or less tolerant to summer's menacing Chinch Bugs in the summer and to Brown Patch in the fall and winter.

Do you drive around the neighborhood and see water abundantly flowing down the street, even from sprinklers in the rain? I do. Some people just do not have time to tend to conservation issues. Water does not cost them enough money to be concerned about it. This is the reason for the tiered volume pricing by the MUD districts. Several agencies including the Water Conservation District is concerned about water resources here in Montgomery County, as well as surrounding counties. Let's dig into this subject and see what our opportunities might be to stave off a water shortage disaster in the next couple of decades.

It is a given that we must shift our potable water from underground resources to surface resources. That source will be Lake Conroe for us, due to the cost of transportation and delivery of the water. That lake is closest to us. Unfortunately, we do have to use potable water on our lawns. It is possible to use recycled water, but the cost of an additional infrastructure, I suppose, is prohibitive. I have lived in a place that used recycled water for lawns and it worked very well.

So how do we water only once per week? Many of us have automatic watering systems. That is the easiest to deploy. A timer is needed to be effective at this. In some areas of the yard, a sprinkler with a timer on the hose can be used without a lot of waste runoff. On automatic systems, we need to do repeat watering. That is, water the landscape several times in one day for the interval needed to deeply saturate the soil. Giving the water an opportunity to soften the ground and allowing gravity to pull the water down into the soil will create an environment for plants to reach deeply into the soil with their roots. For example, a full watering cycle might occur three times during the night, over 8-10 hours. That would be a third of an inch at each sprinkler, released three times. My system allows me to program a time start for the cycle and each group of sprinklers has its own "time on" programmed into the timer. To optimize the time of each group, I measure the water with a can. One idea that I like is to use cat or dog food tin cans. Place them around the yard and measure the height of the water in each one after a full water cycle. Regardless how, make sure you measure the amount of water that you deliver to the landscape. It usually needs one full inch, although some sources say as little as 1/2 inch will do in some cases. Program your automatic system to deliver what is needed. 7

We need to develop a plan for watering our yards and understand what happens when we do water. One inch per week for every part of the yard is just a rule of thumb, but we need to take a look at each plant in the summer before watering time, to see if we are short changing the landscape. The water needs to penetrate the ground, not run off. If it runs off, we have not accomplished our goal. Efficient use of needed water is our goal. Our plants will not survive the once or twice-per-week watering cycle if we don't get all of it deeply to their roots. The water must penetrate some 4-6 inches into the ground. Some plants may even need supplemental watering to 8 inches. That may require aeration or loosening of the soil in some places.

Some helpful hints I have accumulated: (1) Recycle grass cuttings. A mulch lawnmower provides 30% of needed fertilizer and sun protection to the roots St Augustine grass in the hot summer months. (2) In the heat of the summer, grass grows rapidly. Mow late in the before the day before watering starts if you can. That way, the water reaches the ground easier in the evening and there is no blockage or diversion of streamed water from the sprinklers. (3) Try to keep from cutting more than 1/3 of the grass blade. (4) Sharpen or replace your mower blade once a year. It needs to cut the grass, not grind the top off. (5) Don't use a strong fertilizer in the summer months. Use only time released fertilizer or natural fertilizers that will not burn the grass in the sun. (6) Check the sprinkler system and make sure it is adjusted correctly. If it is not and you feel uncomfortable adjusting it, call in a service company. (7) Cut at maximum height starting when the temperature reaches the high eighty's. The roots need the grass shade, especially in places getting the afternoon sun. (8) Apply fungicide in the fall and treat for Chinch bugs in the early and mid-summer months. These bugs drink fluid from the roots and make the grass appear to need water, and of course, the grass DOES need the water, but you will not be able to save it from the bugs by water. (9) If you have an automatic system, install a rain detector to prevent the system from operating when the soil is already wet. Financial help is available from the MUD districts. (10) Cut the recommended amount of fertilizer in half when you use a mulching lawnmower.

In order to conserve water, it is important to plant our landscape for drought conditions. That solves a host of problems. native plants are accustomed to and adapt to the local weather patterns much better than plants brought in from Asia or elsewhere. There are landscapers who specialize in native plants but beware! Some say falsely that some plants are native. What some really mean to say is that they are selling plants that grow and bloom well here. Ask them if the plants originate from this area. That is what we prefer to have for wildlife and the weather conditions. I admit that I have some non-native plants in my yard which are drought resistant. Just be aware of what you purchase and its compatibility with the weather patterns.

St Augustine grass is not a plant that fits well into our weather patterns in The Woodlands. It works much better in climates close to the coast where rain comes in off of the Gulf. We are too far away for that. That type of grass is a water hog, despite what is said by some people. It is not drought resistant and will wither in the afternoon sun. There are other grasses that don't look quite so good but are better suited to our climate. St Augustine is very susceptible to several diseases and insects as well.9 It is a plant that is not very compatible with the strategies of water conservation, although species have been cultivated to resist some of these diseases. 3 Which grass to use is a tough one. I have seen grasses thrive in 120 degree temperatures in Saudi Arabia in sandy soils, watered with brackish water derived from sea water. There exists grass species appropriate for about every climate one can imagine. St Augustine grass is here in our yards because it is pretty. It is not native, except in the Carolinas, nor is it necessarily a contemporary grass of choice for the weather patterns here. It is a choice for beauty and thrives in moist climates, and tolerant to shade. In my view, one cannot legitimately argue that St Augustine is the right choice of grass for water conservation.

Perhaps the Buffalo Grass would be more adaptable as a conservation lawn grass in the long term. It needs to be watered every 21-45 days compared to every 5 for St Augustine (although local authorities say 7).10 This is not a popular view, but I am not trying to be popular, just looking at the issue pragmatically. A legitimate contender as an alternative is the Centipede Grass.11 This one is suggested by one of our local master gardeners. It has a texture similar to St Augustine, can be started from seed and expands out with underground "runners". Centipede requires watering every 7 or so days and needs the same soaking as St Augustine. It is tolerant to shade like St Augustine but not to a lot of walking traffic. Buffalo Grass may not tolerate so much moisture as we have here. Some people eliminate it as a legitimate alternative for that reason alone. It does well in arid areas. The better alternative would probably be Centipede. There are other alternatives such as Bermuda Grass. I love the texture and softness of the turf in a St Augustine lawn. Yet I have seen over and over again the ugly effects of disease and water deprivation.

Centipede grass has probably the lowest maintenance of these warm season grasses that would plant here. It grows on poor, sandy soils to clay based ones, and we generally have a mixture of these two types of soils. One thing to consider if you try another lawn grass - how do you keep really good grass from invading your flower beds? Rhizoid systems that go underground don't respect surface boundaries so one has to build underground boundaries to confine the grass to the yard.

Another issue to consider in water conservation - we must water our foundations in the summer during droughts. I don't know about you, but I don't have an automatic watering system for the foundation. Our concrete foundations are reinforced with row bar that must be sealed off from water to keep them from rusting. Underneath the home we often have a mixture of sand and clay. The clay expands with water and contracts in dry spells. If the walls start cracking, we might be experiencing subsidence due to water depletion in the underground reservoirs or we may be experiencing a shift of soil due to this contracting and expanding process in clay soils. The foundation can crack and that would introduce exposure to termites and generate movement of walls within the home. Watering the foundation helps to stabilize it. The same principal applies - you need an automatic cutoff and use a soaking hose for this, not a sprinkler system.

Resources
1 Woodlands G.R.E.E.N. organization
2 Joint Powers Agency
3 Grow Green Lawn Care
4Watering Your Texas Lawn
5Lawn Irrigation tips from the Joint Powers Agency
6 San Jacinto River Authority">Groundwater modeling for Lone Star Conservation District, 2008
7Beautiful Lawns the wise way, The Woodlands Association 9Forida Turf - St Augustine Grass
10Buffalo Grass - Texas Wildscapes
11 Centipede Grass

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