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Fertilizing and Mowing your Turfgrass

Before this cold spell, most turfgrass was starting to grow and green-up. This time of year, we get a good many calls about fertilizing turfgrass. The cold weather will set things back a bit, but it is time to think about fertilizing and maintaining your turfgrass. Here is some good rule of thumb recommendations. Apply approximately 1.0 lb. of actual nitrogen per 1,000 square feet. Ideally, the amount of phosphorus (P) and potassium (K) applied along with the nitrogen should be determined by soil test results (fertilizer ratio). Many of our soils in Texas are high to very high in phosphorus and potassium and in these cases all you need to apply is straight nitrogen. If a soil test has not been conducted, then a 4-1-2 to 3-1-2 fertilizer ratio would be recommended. Not all soils are high in phosphorus and potassium and if you are applying only nitrogen, and your soil is deficient in P and K then the turfgrass will become stressed.

In heavily shaded areas, apply 0.5 lbs. of total nitrogen per 1,000 square feet, unless this is the only application that is going to be applied to the heavily shaded portions of the lawn. Excess nitrogen in shade will eventually cause major problems for the turfgrass growing in these areas. Depending on type of turfgrass, soil type, environmental conditions (sun vs. shade) and level of maintenance desired, make a second application in approximately 5 to 6 weeks after the spring application. If you are not sure of your lawns measurements, take a few minutes to walk it off and figure up your square footage. This will help prevent the over or under application of fertilizer and other lawn care products.

Setting your mower to the right height and mowing timings can make a big difference in the thickness and health of your lawn. Mowing the lawn at a lower height and more frequently will force the turfgrass to spread faster and form a denser stand of turfgrass. The key is to mow the turfgrass often enough so that you never remove more than 30 to 40% of the leaf blade when the grass is mowed. Removal of excess leaf tissue inhibits the plants ability to carry on photosynthesis properly, which means that the plant cannot produce enough food for new growth, especially new leaf growth.

Mowing frequency is going to be determined by height of cut and growth rate. The lower the grass is mowed, the more frequently it needs to be mowed. The more the grass is fertilized and watered, the more often it will need to be mowed. Mowing at the proper height and frequency will produce a denser stand of turfgrass, a deeper root system and more stored carbohydrates in the plant. However, frequency will vary during the year due to day length differences and changes in temperature. In the fall and spring, when we have longer nights and cooler nighttime temperatures, the warm season grasses are not going to be growing as fast as they will in late spring through early fall months. Listed below are the recommended mowing heights and frequency for turfgrasses growing in home lawns.