 |  |  |  |  |  |  |
| TURF GRASS SELECTION The following series of articles, written by Geo Growers owner George Altgelt, appeared in the Dripping Springs Outlook Turf Grass Selection (Article #1) and, most importantly, how much water will it require? Quite and, most importantly, how much water will it require? Quite often, the most recommended grass is the most disappointing. Here I am speaking of Buffalo grass. Yes, it’s the most drought tolerant of all grasses but it will not take foot traffic, it will not grow in the shade, and the soil you plant it on top of must be relatively fertile and weed free or the weeds will take over. You must also be prepared not to mow it. That may seem like a strange drawback for a turf grass but here’s what happens: A few weeds show here and there in a stand of buffalo and the caretaker makes a decision to mow rather than pull, this is the beginning of then end. Once the grass is cut it loses its competitive advantage of shading the soil. The weeds can handle the hotter drier soil and they quickly make use of the increased light. After a few more mowings it will not look like the original vision of a prairie. prairie. This weed problem can be avoided of course with the placement of a two-inch layer of a weed-free, fertile soil blend. This excludes Sandy Loam, which has no water holding capacity, leaving it a mud pie under wet conditions and a brick when dry. This material is so totally dead and infertile that it becomes a waste of money to amend it. Living soils must have organic matter in them in order to support microbial life, hold water, and recycle nutrients, especially nitrogen. Sandy Loam’s high PH rating, 9.4 in some cases, destroys organic matter. The caretaker winds up having to fertilize often, use toxic substances to control pests and weeds, as well as water all the time. With the correct soil none of this would be necessary. A living soil enables a lawn to go long spells between watering, never needs fertilizer, and never ever needs toxic rescue chemicals which will poison our well water and stock tanks. Next month more on turf grass selection. Turf Grass Selection (Article #2) Just as I promised there will be more discussion on turf grass selection this month. However, now is an excellent time to explore the fundamentals of soil structure and function as it pertains to turf grass production. Understanding these things will lead us directly to the satisfaction and bliss that comes from that sea of green turf grass that we grow ourselves. Any turf grass can be considered as a crop, and, as such, requires real fertility to overcome weeds and to be able to handle environmental stresses such as too hot, too cold, too wet, too dry, too much foot traffic etc. Consider the fertility factor of “loft.” Loft is how fluffy a soil is. How fluffy it is, is a factor of how easy it is for a grass to grow its roots and runners through it. Loft is also a factor of how easily a soil will absorb water, as opposed to it running off into the creek along with the fine particles of your remaining topsoil. Loft is also a factor of how soil breathes. That’s right, you read it right, how soil breathes. Soil breathes? How does it do that, and why is that necessary? The microbial life in the soil, the ones that live in symbiosis with the grass roots (and many others) are air-breathing microbes. They must have a fresh supply of oxygen to digest carbon for energy and do the work of transporting water, foods, and minerals into the plant's root system. If the available oxygen is limited, the work the microbes do is also limited. For the plants (turf grass in this case) the limited microbial activity means less water, nitrogen, trace minerals, phosphorous, calcium, and all the rest. The plants growth slows down, it loses its vigor. Weeds, pests, and pathogens can and will take advantage of this. Oxygen rich soils counter all this mayhem and make your lawn healthy and strong. So how does this fluffy soil breathe you ask, having never seen it heave up and down, at least not while you were looking. It breathes, so to speak, with changes in barometric pressure, even minute changes. This is what pumps air into and out of the soil. Oxygen is not the only gas going in and out of the soil; there is also nitrogen, and that’s free nitrogen for your crop or turf grass. There are microbes not associated with legumes that also fix nitrogen into the soil and make it available to plants. These are called azotbactor microbes. This one factor referred to as soil loft is probably the most unsung hero of soil fertility. Next month more on turf grass selection. Turf Grass Selection (Article #3) As promised, this month we’re going to talk about turf grass selection. The best question, as always, is: “What do you want it to do?” We’ll start with the amount of water it will use. The real question is how much water you’re going to put on it – enough to keep it green or just enough to keep it alive? For all four turf grasses (Buffalo, Zoysia, Bermuda, St. Augustine), the answer is “none” to “a lot ” depending not on the type of grass but the soil under it. For example, there is a home in Oak Hill that has had a lawn around it for 25 years. In this area there have been some pretty tough droughts in that time period. However, in all that time, the owners have never watered it. Or fertilized it, or poisoned it, for that matter. They don’t do anything for their yard except occasional mowing. So what is this grass? It’s St. Augustine! That’s impossible, right? Everything you’ve heard says that can’t be true. Remember that the success or failure of plant life is a reflection of the soil ecology that sustains it. This lawn is planted on rich bottom land – in this case, pecan bottom. The shade from the trees is also a factor. You could not grow Buffalo grass and Zoysia wouldn’t do very well. So how brown does the grass get in a drought with no one watering it? Pretty brown, certainly, but its resilience is sustained by the living soil underneath it. That rich soil is what creates a drought-tolerant lawn of St. Augustine grass. And how, exactly, did they do that? Simple! They didn’t water it. Next month we’ll continue the selection process by examining such things as the amount of foot traffic expected. That includes all kinds of feet: dogs, kids, party guests, neighbors, militant pamphlet distribution agents, and other assorted groups of curious onlookers. ‘Til then, HAPPY LANDSCAPING! Turf Grass Selection (Article #4) The selection process for turf grass, based on “What do you want it to do?”, has now reached the question of foot traffic. Buffalo grass, while beautiful to look at from a distance looks lousy up close after a party or a Bar-B-Que. It looks obviously trampled and does not recover quickly. Zoysia fairs much better, however it does not bounce right back after an event. Bermuda will show signs of being walked on and is very reliable when it’s time to re-grow and recover. However, Bermuda is not much fun to play on (for kids and adults alike), walk on or romp on because it’s so thin. Bermuda grass has no cushioning effect. When it comes to foot traffic, recovering from parties, romping and rough-housing one grass stands out from the rest. That grass is St. Augustine. I’m not just speaking from my own experience; this is the same answer I get from professional lawn maintenance providers. Every time I ask that question the answer that comes back is always the same, “Yeah, if you want a grass that stands up to foot traffic, St. Augustine is it.” The people I’m asking this question of are knowledgeable and experienced professionals who have been in business a long time. These are not the kind of people who lower their lawn mowers in hot weather just because the grass stopped growing and they want to make it look like they did something. Now that the subject of “How tall should the grass be?” has been brought up, let me say that it is an intricate and important part of water conservation, soil health, and the subject of next month's column. This is also taking us in the direction of why water conservation is connected to traditional water rights and why that is becoming a hot, if not explosive political issue. Till’ next time, HAPPY LANDSCAPING Turf Grass Selection (Article #5) How tall should turf grass be? Well, what do you want to end up with? Something nice to walk on? The manicured look? Easy maintenance? Minimum water usage? The best place to start is with a look at the physics of light and heat. When sunlight reaches the surface of almost any given object it is absorbed and turned into heat. Heat is a form of light (infrared) that can travel through solid matter, i.e. rocks, concrete, pavement, bricks, soil, shoestrings, soap bubbles; you name it and heat can move through it. Heat moves faster through things that are dense and slower through things that are fluffy. There are, however, instances when light is absorbed that it does not become heat. Say for instance when light strikes a green leaf or blade of grass. What happens next is a wonder, a miracle, an event so awesomely complex that no computer yet devised can track even one second’s worth of activity taking place within a single cell of the simplest plant. What we do know however, is that instead of turning into heat the light is used via the agency of chlorophyll, to make sugars, carbohydrates, fats, and proteins which are organized into larger structures called plants. In short, light is used to drive the biological machinery of plants instead of turning into heat. The rest of us life forms who cannot do this are deeply in their debt. If you have a lawn of green grass, light striking it is used up powering the biological reactions that grow the grass. Some of the light reaches the soil and is turned into heat. Taller grasses mean more light is used up driving biological processes and less is absorbed by the soil and turned into heat. Cooler soil means soil that holds more water. Soil that holds adequate water not only provides for the needs of the plant populations growing in it and on it (not just grass), but also becomes a hospitable habitat for a very large array of soil microbes. As mentioned earlier these air breathing microbes do the work of making nutrients available to plants. Taller grasses, cooler soil, greater water retention, and better soil ecology. |