There are many environmental stresses that affect our lawns: drought, heat, insects, weed seeds blowing in from neighbors etc. Unfortunately we do not have much control over these stresses. But we do have control over one necessary stress: mowing. This is something that you should keep in mind, that mowing is actually stressing your lawn, it’s not helping it. Grasses are the best equipped plants on earth that can tolerate this type of defoliation, but there are certain guidelines we can follow to mow properly to reduce this stress to a minimum.
One of the most important facts is to remember that the lower the mowing height, the greater the stress.When grass is mown at extremely low mowing heights, it is under considerable stress due to the constant tissue removal. Under these circumstances, your lawn is more susceptible to diseases. A low mowing height also encourages weeds. With less tissue cover, there is more sunlight to reach the soil to encourage weed seed germination. Also, when your lawn is under stress, it cannot out compete these germinating weed seeds. The shorter the lawn, the greater the weed population. When a lawn is mowed short, grasses compensate the loss of tissue by becoming more dense over time. The carbohydrates that are channeled into the formation of higher shoot density are not available for root growth. This results in less root mass and a shorter depth of rooting.You can imagine that this adds to the stress. Less roots equals less water and nutrient uptake.
When mowing, you should remember never to remove more than 1/3 of the leaf tissue at a time. Removal of more than this in one mowing can cause your roots to stop growing for a period of 6 days to 2 weeks. Lowering the height too quickly can also result in a condition called scalping. Scalping occurs when too much tissue has been removed at one time, causing the shaded portions of the grass to be exposed to sunlight. In the heat of the summer, this will cause your grass to burn. If the lawn has a yellowish or brownish cast immediately after mowing, that’s a sure sign that it has been scalped.
So you may be wondering, so how short can I mow? Below is a table of MINIMUM mowing heights for different types of grass species. Do you have a lawn with several different kinds of grass? Go by the species with the highest mowing height.
|Species||Cool Weather||High-Temp Stress Period|
|Kentucky Bluegrass||1.50 -2.25 inches||2.25 -3.00 inches|
|Perennial Ryegrass||1.50 –2.00 inches||2.00 –3.00 inches|
|Tall Fescue||1.75 –3.00 inches||2.50 –3.50 inches|
|Buffalograss||1.0 inches to unmowed||Not applicable|
|Fine Fescue||0.50 –2.00 inches||1.50 –3.00 inches|
Mowing frequency depends on how short you are going to mow. A lawn mowed at 2 inches will need to be mowed about once a week. Establishing proper mowing frequency is important. Mowing too frequently places extra stress on the turf from water loss and excess traffic. Infrequent mowing may result in scalping and a buildup of clippings on the surface that can contribute to diseases and other problems. Following the rule of not removing more than 1/3 of the clipping in a single mowing is the best guide.
Should you remove the clippings from your lawn? Many believe that not collecting your clippings contributes to a thick thatch layer, which in turn can decrease water penetration, increase disease potential, and harbor insects. In fact, most of our thatch buildup comes from the natural death of roots, rhizomes, and old leaf sheaths. A thick thatch layer is caused by the excess growth of these structures cause by excessive nitro-gen and excessive watering. Watering too much creates an anaerobic (low-oxygen) condition, which kills off the microbes that break down this thatch layer. Returning your clippings to the soil is actually very beneficial because it can add up to 2 lb. N/1000ft2/yr. The only time that clipping removal would be suggested would be if there are weeds in flower or you’re planning to remove a lot of grass in a short amount of time.
Over all, grass is an amazing plant that can tolerate many environmental stresses, and even some cul-tural stresses such as mowing. If you follow these guidelines on mowing height, frequency and clipping re-moval, you can greatly increase your lawn’s ability to combat diseases, weeds and our hot dry summers.
Treating your lawn for insects isn’t the only preventive step you can take in the spring. The cold temperatures severely limit the effectiveness of almost every herbicide (so don’t bother trying to kill your dandelions until the daytime temperatures reach at least 70 ̊-75 ̊). However, the weather of early spring offers perfect conditions for applying a preemergent to stop the weeds in your lawn before they start.
The one thing to remember with preemergent herbicides is that unless you have a serious problem with these types of weeds, the cost usually outweighs the benefits. If you had spurge, chickweed, or crabgrass taking over areas of your parking strip or lawn this fall, the All Seasons Barricade will prevent the seed of these pesky weeds from germinating and infesting your lawn again this year. Generally, this herbicide will last from 6-8 weeks and should be applied so that it can reach its peak effectiveness when the weed seeds are germinating (usually in April). Gallery, a broadleaf preemergent, prevents dandelions, mallow, and other broadleaf weeds from germinating. Unlike the others, Gallery lasts up to 9 months, and can be applied in early spring or late fall. Again, try and assess the seriousness of your weed problem, then consult with your local garden center to find the product that best suits your needs.
Second, you can spray your lawn with a broadleaf herbicide. Trimec has always worked well for me, but there are many other excellent herbicides that will eliminate broadleaf weeds without damaging your grass. For really hard to kill weeds, such as morning glory and wild violets, you will have excellent results with Triclopyr (Turflon Ester). The newest product on the market is a weed killer called Weed Free Zone. This is an excellent product if you want to kill all kinds of weeds, even the hard to kill ones, and not pay as much. Remember, however, that most herbicides for your lawn work best when the temperature is above 65-70 ̊, but does not exceed 85. Also, the weed killer must stay on for at least 24 hours without being washed off to re-main fully effective.
Third, you can apply a weed-and-feed. This is by far the easiest way to fertilize and kill weeds, but it needs to be timed just right to work properly. The grass must be damp when it is applied, so that the herbicide will stick to the weeds. Leave it on for 24 to 48 hours, then water it in to wash the fertilizer off the grass and into the soil. If you decide not to use a weed-and-feed, May is an excellent time to apply your second dose of fertilizer. Sprays and weed-and-feeds and preemergents can definitely alleviate some hard work, but these products are only aids to help the gardener in the never-ending war against weeds. Don’t expect miracles. A hoe, gloves, and a pair of hands (the more pairs the better) are still the best weapons against weeds. They’re fairly cheap too.
One common problem for many homeowners in Cache Valley is thatch. So what is thatch? Most lawns will normally show some scattered, dried-up grass clippings, or brown patches, but don’t worry, these are not thatch problems. To identify thatch (a visible, thin layer of dead, decomposing grass clippings just under the grass, on the surface of the soil), you must look closely at the turf itself. A thin layer of thatch (about1/8 to 1/4 inch deep) is beneficial. Too much thatch (1/2 inch or more), however, can create problems, such as, promote disease, reduce the effectiveness of fertilizers and pesticides, and prevent water and light penetration.
Normally, the only recourse for thatch is the power-rake, which can damage your turf. Another way to get rid of thatch is to apply humate, or humic acid, that naturally “composts” thatch right in your lawn. Humates contain all the trace minerals and nutritional substances not found in chemical fertilizers (such as organic matter, carbon, protein, chlorophyll, and humic acid) necessary to the development of plant life. They also serve as a home for microorganisms. These microorganisms are the culprits that actually convert the thatch grass clippings and organic matter in your lawn into soil. Not only do they compost your thatch, but they also free up unavailable nutrients in your soil, increase water retention, assist in soil aeration, improve seed germination, and enhance root development.
Aeration and Humate
One problem spot you commonly see around the valley is sloped turf. If you have lawn on a slope that keeps burning up because the water just runs off of it instead of soaking in, you might want to consider aerating. The water must get down to the roots and aeration will provide a way for that moisture to penetrate hard, sloped soil. The best time to aerate is in the fall when your grass is going dormant and not actively growing, which in turn will cause less damage to the roots. Humate has also proven very effective against dry conditions, and you will find your turf holding in more moisture. Also, if your soil has a lot of clay, aerating once a year for about 3 or 4 years will help break up the clay and let in more water and oxygen into the root system.
As we all know, water is a valuable resource. Did you know 61 % of all our water use is used to water our landscapes? Our lawns are often the heaviest users of this precious (and expensive) resource. Therefore we have the responsibility to make sure that we are watering our lawns in the most efficient way possible. Here are some tips on how to accomplish this worthy goal.
Learning how much and how often to water our lawns is an art that comes with experience. Having a better understanding of your soil; learning key signs when to water and knowing the efficiency of your irrigation system can give you a good start. Let’s begin by discussing how much water your grass needs. On average, turf usually requires 1 to 1.5 inches of water per week for normal maintenance conditions. Of course this will depend on your local environmental conditions such as heat, humidity, and soil type but these numbers will give you something to start with.
How Soil Type Affects our Watering
Knowing the type of soil that you have is a good step in creating an efficient irrigation program. Soils are typically made up of three mediums: sand, silt and clay. Often we have a mix of some sort of these three types. The more sand there is, the more drainage you have, and the faster your soil will dry out. This will mean that you may need to water more often, with shorter watering cycles.A soil heavy in clay has bad drainage and often cannot soak up water very quickly but dries out slower. A clay-loamy soil is the best type for proper rooting and drainage. If your soil is not corrected before you plant your lawn, it’s very difficult to change it later. But for most of us, this is the case, and here are a few ways to help improve your soil structure.
Compaction can restrict rooting of grasses that would normally develop a deep, extensive root system. Aeration in the fall is the one of the best ways to open up air pockets for better drainage, and to allow oxygen in our soils for better microbial activity. Adding humate (a naturally occurring fossilized organic matter), greatly improves our soil structure by increasing the cohesive forces of very fine soil particles (clays) and promotes drainage and water intake. Humate also has a high water holding capacity which is very beneficial in sandy soils.
How often should you water? Many homeowners make the mistake of watering several times a week at short intervals, when in fact they are actually creating a shorter root system! Plant roots only grow where there is water!If we water for short periods of time, thus keeping the water in the upper portions of our soil, the roots will stay that short and thus stress out when there is a shortage of water. The rule of thumb for most turf is deeply and infrequently!We recommend you water twice a week, adding .5 -.75 inches of water each time. Timing for this amount will be discussed later.
Signs of When to Water Your Lawn
Your lawn will tell you when it needs to be watered, don’t just water every Tuesday and Saturday (unless you don’t have a choice). Water only when your lawn needs it. Here are some sure signs that you can use to know if your lawn needs watered. Grass blades will roll up lengthwise to conserve moisture. At the same time, they will start to slightly lose their green color, and have a grayish cast. Thirsty plants also lose their resiliency, so if you walk across a lawn in need of water, the grass will not spring back,and your footprints will remain visible. This may sound like you are letting your lawn stress too much between waterings, but the long-term effect of this slight wilting is a thickening of the cuticle (the outer layer of a grass blade, kind of like a skin) and the development of a more extensive root system. Another effective way for determining water needs is to take a long bladed pocket knife or screwdriver and trust it into the ground. Dry soil will resist the penetration. At first, make sure to poke at the soil right after you water and everyday after that so you get used to feeling what a well watered soil should feel like when penetrated with your screwdriver or knife.
Water Saving Tips
We cannot control how much water our grass actually uses, but we can control, to some extent, the efficiency of that use. Here are some water saving tips:
Proper mowing can greatly increase your root mass and depth. Mowing higher during periods of stress will actually pro-mote a stronger, deeper root system that can access deeper water resources. The extra leaf tissue also helps to shade the crowns of the plants during hot, dry weather.
Proper fertility management can increase your grasses root system. Grass that is deficient in nitrogen, iron, magnesium of any of the other nutrients that affect chlorophyll formation, will not undergo photosynthesis enough to the supply their roots with the carbohydrates they need to grow and survive. Properly fertilized turf will be much more efficient at using available water.
Water early in the morning!Watering during the day (between the hours of 10am and 6pm) is a huge waste to evaporation. You should also not water at night. Excessive water in the canopy of your grass blades can lead to disease problems down the road. If you water at night, your blades do not dry out quick enough. Watering in the morning allows for lower evaporation, and quicker drying time.
Control your weeds!Pull or spot-spray weeds to eliminate them and prevent them from competing with your grass for moisture.
Use water retaining products! Humate and a product called Zeolite have an amazing water holding capacity that can greatly increase the time between waterings. Ask an Anderson associate more about these products and how and when to apply them.
Now that we have a better understanding of our soil, signs of water needs, and water saving tips, let’s focus on knowing how long to water your lawn to achieve that 1-1.5 inches per week! As we now know, timing will be different for every type of irrigation system whether you have to drag hoses, or have a sophisticated underground irrigation system, BUT the calculations are the same. Don’t worry, just grab a calculator and a ruler, and we’ll tell you just what to do.
First you need to determine how efficient your sprinklers are. To do this, collect several containers of the same size, such as tuna fish cans. Place these cans at equal distances from all your sprinkler heads in a grid like pattern over your lawn. Run your sprinklers for 10 minutes. When this is done, measure the depth of water in each cup and record those numbers (if the measurements are too small, run your sprinklers for longer). Average all the measurements. Then take the lowest 25% of the numbers and average those. For example, if you placed 12 cups around, then take the lowest 3 measurements and average those. Now take your Low Average ÷ Total Average then multiple by 100. This number will give your Distribution Uniformity (DU) percentage. 80% is a good target, but anything less then 70% will indicate that you need to adjust your sprinklers for better uniformity.
Now let’s take these numbers and figure out how much water your system puts out in inches/hour. Take your Total Average ÷ running time (10 min or other). Then multiply by 60. This will give you your Application Rate in inches/hour. But as we figured our earlier, your system is not uniform, so we must take this into account. Take your Application Rate ÷ Distribution Uniformity. This is a fairly accurate number you can go by to determine how long you need to run your sprinklers to get 0.5 to 0.75 inches. For example, if you came up with your Application Rate as being 1.25 inches per hour, and you determine .5 inches is how much you want to water, 0.5 in. ÷ 1.25 in./hr then multiply by 60 to put it into minutes. In this case you would need to run your sprinklers for 24 minutes to put out 0.5 inches of water with your particular sprinkling system. See, wasn’t that easy? Now you know exactly how much you need to water to achieve a certain depth.
In conclusion, our water is a very precious resource, and if we can use these tips on how to make our irrigation system more effective by understanding our soil; knowing signs of water needs; applying water saving strategies; and measuring the exact time it takes to water your lawn, you can more effectively help in the great goal of water conservation.