How often should one mow a lawn in Texas so the grass does not burn out? How high should the mower's blade be if mowing is done weekly?
I live in McKinney, Texas. The mowing service will do the mowing weekly only.
Lawns are one of the most manipulated and high-maintenance areas of the modern-day landscape. The seeds are highly hybridized and specially manufactured. The cultivation of the seed, once started, is specialized and involves a somewhat complex dance between soil, water, and cultural practices in order to produce what is considered a good-looking lawn today.
That said, there are no really simple answers to questions about lawns. That seems strange given that we will hire just about anyone -- from a high-end landscape maintenance company, to the neighbor's kid -- to take care of them. Soil, water, and cultural practices all contribute to burnout in a lawn, so this answer will touch on all three.
Soil. Ideally, the soil your grass grows in needs to be aerated, and have a balance of organic materials and different-sized particles ranging from sand to small pebbles with some clay mixed in. Most lawns, however, are grown in almost exactly the opposite circumstances -- compacted soil that has almost no gas movement in it. A recent article in the New York Times about the lawns of Harvard University indicates that a natural lawn fed through regular compost tea applications will help convert highly composted soil to something alive and aerated. However, if you are committed to chemicals and have compaction, you need to aerate your lawn with a core aerator at least once per year, preferably in the fall.
Water. Water is an important component here. Assuming your soil is aerated, water will move into it and be retained better. Grass likes heavy infrequent watering, once or twice a week. Weeds like light frequent watering three times a week or more. Cutting back watering days is great for the lawn, but in a warmer climate like McKinney, which is just north of Dallas, make sure you water deeply and in the evening to limit evaporation and insure the sod has time to absorb the water.
Cutting. Cutting is a cultural practice. In cooler weather when your lawn is growing like crazy, let’s say up to 85 degrees Fahrenheit, you can keep your lawn shorter (1” to 2”) bearing in mind that the shorter you keep the grass, the more likely it is to burn. You can do this weekly, or more frequently, but less than weekly in the spring increases the chance that you will cut too much of the blade and break the 1/3 rule (don’t cut the grass by more than a third of its height). During the hot months you will want to keep your lawn at 3” so that there is less evaporation. Longer blades also encourage deeper roots and better moisture retention. Studies show that organic lawns consistently have better root development than chemical lawns and deeper roots means less likelihood of burnout.
Other reasons for burnout can be too much nitrogen, or over-fertilization. If you have dogs, they over-fertilize the lawn every time they urinate on it, so much so that the industry has coined the term “female dog spot disease” for areas burned by female urination (females tend to drop it all in one area while males share the joy with trees and shrubs). Additionally, if you cut the grass by more than one third of its height, this exposes more tender areas of the blade and increases the chance of burnout. In fact, if you follow the one-third rule, and stick to the seasonal height recommendations, you will find that in the summer you may mow every ten days to two weeks while in spring and fall you may mow weekly.