A new research project at the West Florida Research and Education Center in Jay, FL is looking into the quality of turfgrass cut with a robotic mower. The study is to determine whether the quality of St. Augustinegrass can be improved by continuous mowing with a robotic mower at 2.4″ height instead of the traditional mowing height of 3.5″, removing only a third of leaf blade material per mowing.
Dr. Shaddox talking to participants at the 2018 Gulfcoast Expo & Turfgrass Field Day. Photo Credit: Matt Lollar, University of Florida/IFAS Extension.
The mower being tested is the Miimo manufactured by Honda. This particular model mows and charges on its own and can mow up to 0.37 acres on one charge. It can mow in three programmable cutting patterns: directional; random; or mixed. The study is utilizing the random cutting pattern.
The mower’s three, two-sided blades are mounted on a circular head that can rotate both clockwise and counter-clockwise. The head automatically switches between clockwise and counter-clockwise rotation to reduce wear on the blades. The blades are basically just two-sided razor blades. A buried guide wire is installed on the perimeter of the lawn to serve as a boundary.
A close-up shot of the Miimo mower blades. Photo Credit: Matt Lollar, University of Florida/IFAS Extension.
So far, the plots cared for by the robotic mower look promising! The blades on the robot are much finer than those found on a common rotary mower. Because of this, they cut more cleanly and tend to tear the grass blades less often than the rotary mower. Other robotic mowers on the market include the Worx Landroid, Husqvarna Automower, and Bosch Indego. Please stay tuned for future robotic mower evaluations on other products, energy consumption, and nutrient evaluation.
Northwest Florida has experienced an enormous amount of rain this summer. The western panhandle has received over 29 inches of rain since the beginning of May according to the Florida Automated Weather Network station at the West Florida Research and Education Center in Jay, Florida. That is 44% of average annual rainfall in less than two months. All of this rain has probably thrown off the normal lawn mowing routine. It is hard to get out and mow the lawn when its pouring buckets or the lawn resembles a swamp. With all of this in mind, there are a couple of mowing pointers that would be useful to implement to address the out of control lawn growth and the challenges posed by not being able to stick to normal mowing schedule.
- Always attempt to mow at the IFAS recommended height for your species of turfgrass. The recommended heights are determined by how quickly the species grow in our climate. The chart below shows the best heights at which to mow your lawn. The fine textured zoysiagrasses are not listed but should be mowed at 0.5 to 1.5 inches. Check the lawn mowers mowing height by measuring the distance from the ground to the bottom of the mowing deck on a flat surface.
From Mowing Your Florida Lawn: http://edis.ifas.ufl.edu/pdffiles/LH/LH02800.pdf
- When you do get out to mow, never remove more than 1/3 of the leaf blade. If you cut to short you will “scalp” the turf and cause a brown look on the lawn. This can be damaging to the turf and allow for weeds to get established by exposing the soil to the sunlight. What is taking place more in northwest Florida is not mowing frequently enough and cutting off excess growth due to the rain. This also can cause scalping so it is very important to mow frequently enough to only remove 1/3 of the leaf blade.
A zoysia lawn that has been “scalped” after excess growth and infrequent mowing. (Photo Credit: Blake Thaxton)
Other practices such as keeping your mower blade sharp, mowing in different directions, and leaving clippings on the ground will help keep a healthy Florida lawn. Please see more information about mowing correctly in Florida in the University of Florida/IFAS Extension publication: Mowing Your Florida Lawn
Sometimes when we talk about the size of things we like to estimate and don’t worry too much about being precise, but there are times when as little as a half inch really is a big deal. When talking about landscape maintenance and pest management that half inch can be crucial.
Here are three examples of when less than an inch may be significant.
Bermudagrass lawn cut at half-inch different height. Photo: Julie McConnell, UF/IFAS
Mowing your turf. If you read Mowing Matters last month, you saw mowing height recommendations for common turf types grown in north Florida. We gave a range of heights, but besides referring to the handy chart, you need to pay attention to your specific site. If you begin to mow and the current setting is too low, shut down the mower and adjust the height.
In this picture you can see that just raising the deck up one-half inch prevented the entire yard from being scalped and put under additional stress. After less than a week of proper irrigation the scalped area recovered and the yard looked uniform to casual inspection.
Treating Mole Crickets. The common knee-jerk reaction to seeing adult mole crickets during a mating flight is to treat the lawn. However, when you see the adults they are past the stage of being susceptible to most pesticide treatments. It is also too early to target the next generation – after all you are witnessing mating flights, so time is needed for egg maturation, hatching, and nymph development and feeding before treatment will be effective. Depending on several factors such as temperature and soil moisture nymphs will become active anywhere from 2 weeks to 2 months after adults are seen.
Adult and nymphs of mole crickets. Photo: Julie McConnell, UF/IFAS
Before applying any pesticides, be sure to scout for appropriate life stage (nymphs approximately ½ inch long) and action thresholds of mole crickets by performing a soap flush (details can be found here Mole Cricket IPM Guide for Florida).
Turf Irrigation. It is important to calibrate your irrigation system and make sure that each turfgrass zone is putting out a minimum of one-half inch of water uniformly.
Why this amount? Research has shown that in most Florida soils application of one inch of water will reach the top twelve inches of soil. Healthy turfgrass roots are typically found in the top 4-6 inches of soil, so by applying one half-inch of water per irrigation cycle you should deliver water to turf roots.
To see an example of how to calibrate your system watch this short video demonstration by Dr. Laurie Trenholm, UF/IFAS Turfgrass specialist.
Properly Mowed Empire Zoysiagrass – Image Credit Laurie E. Trenholm
Mowing is an important and often overlooked landscape best management practices that can increase lawn health.
Most of us mowed lawns to earn some spending money as kids. As long as it was shorter when we finished than when we started our customers were happy. Although mowing seems like a simple chore that anyone can do, it turns out that improper mowing can cause a lot of damage to lawns and can increase pest and disease issues.
Make sure your lawn mower in good working order. Ensure the blades are sharp and the engine is not leaking any oil or gas products that may damage your lawn. Dull or damaged blades will give a ragged cut to grass blades that make it easier for disease and insects to attack your lawn. Leaking fuel products can damage or kill turf. Keep your mower clean by blowing or rinsing it after use, this simple step will also reduce the spread of weeds, insects, and disease.
Know the recommended mowing height for your type of turf (see table below) and follow it! Cutting turf below the recommended height places stress on the grass and encourages shallow roots. Deep roots help turf handle stresses such as drought, shade, insects, disease, or traffic. If any of these circumstances are occurring, the mowing height should be increased and fertilization should be decreased.
Mowing Height Table
||Recommended Mowing Height
||3.5-4.0 inches, Dwarf Cultivars 2.0-2.5 inches
||1.5-2.5 inches, cultivar dependent
When mowing, never remove more than 1/3 of the leaf blade per cutting. If the grass is overgrown, plan to mow in stages to avoid scalping or removing too much of the leaf blade. Just like shrubs, turf needs leaf surface area for photosynthesis. Allow clippings to fall onto lawns rather than catching them or discharging onto hard surfaces. The grass will decompose rapidly and provide nutrients to the lawn. Clippings that are blown onto sidewalks, streets, or other hard surfaces may be washed into storm drains and get into water systems. Just as decomposed clippings provide helpful nitrogen and phosphorus to our lawns, these same nutrients are harmful to our water bodies. Keeping them in lawns is a great way to recycle and to keep our water clean.
To learn more about caring for your turf click on the link below.
Bahiagrass for Florida Lawns
Bermudagrass for Florida Lawns
Centipedegrass for Florida Lawns
St. Augustinegrass for Florida Lawns
Zoysiagrass for Florida Lawns
“We have replaced this grass several times over the past few years; and it’s dying again.” I have heard this complaint too many times this summer. Last summer’s heavy rain, the stress of January’s icy weather, and this year’s extended summer have contributed to widespread outbreaks of Take-All Root Rot, a soil-inhabiting fungus Gaeumannomyces graminis var. graminis.
Symptoms of Take-All-Root-Rot. Photo credit: Sheila Dunning, UF/IFAS.
This disease causes yellow grass patches ranging in diameter from a few inches to more than 15 feet. The symptoms first appear in the spring, but the disease can persist all summer and survive the winter. Over time, the entire area dies as the root system rots away. The pathogen is naturally present on warm-season turfgrass roots. High rainfall and stressed turfgrass trigger the disease.
Since the roots are affected, they are not able to efficiently obtain water or nutrients from the soil, nor are they able to store the products of photosynthesis, which result in the loss of color in the leaves. By the time the leaf symptoms appear, the pathogen has been active on the roots for several weeks, probably longer; the disease has been there potentially for years. If the turfgrass is not stressed, leaf symptoms may never be observed.
This disease is very difficult to control once the aboveground symptoms are observed. Measures that prevent or alleviate stress are the best methods for controlling the disease. Any stress (environmental or manmade) placed on the turf weakens it, making it more susceptible to disease. Remember, that every maintenance practice, fertilizer application, and chemical (especially herbicide), application has an impact on turfgrass health. Cultural practices that impact the level of stress experienced by a lawn include:
- proper turfgrass species selection
- mowing at the correct height
- irrigation timing, frequency and volume
- fertilizer: nitrogen and potassium sources and application quantities
- thatch accumulation, and
- soil compaction
The selection of turfgrass species should be based on existing soil pH, sunlight exposure, use of the area and planned maintenance level.
Mower blades must be sharp to avoid tearing of the leaves. Additionally, turfgrasses that are cut below their optimum height become stressed and more susceptible to diseases, especially root rots. When any disease occurs, raise the cutting height. Scalping the grass damages the growing point. Raising the cutting height increases the green plant tissue available for photosynthesis, resulting in more energy for turfgrass growth and subsequent recovery from disease.
If an area of the lawn has an active fungus, washing or blowing off the mower following use will reduce the spread of the disease to unaffected areas.
The amount of water and the timing of its application can prevent or contribute to disease development. Most fungal pathogens that cause leaf diseases require free water (rainfall, irrigation, dew) on the leaf to initiate the infection process. Irrigating every day for a few minutes is not beneficial for the turfgrass because it does not provide enough water to the root zone, but it is beneficial for turfgrass pathogens. It is always best to irrigate when dew is already present, usually between 2 and 8 a.m., and then only apply enough water to wet the root zone of the turfgrass.
Excessively high nitrogen fertility contributes to turfgrass diseases. The minimum amount required for the grass species should be applied. Potassium (K) is an important component in the prevention of diseases, because it prevents plant stress. Application of equal amounts of nitrogen and potassium is recommended for turfgrass health. When turfgrass roots are damaged from disease, it is beneficial to apply nutrients in a liquid solution. However, nitrate-nitrogen increases the severity of diseases, so their use should be avoided when possible. Ammonium-containing fertilizers are the preferred nitrogen sources.
Heavy liming has also been linked to increases in Take-All Root Rot. Since most turfgrasses can tolerate a range of pH, maintaining soil at 5.5 to 6.0 can suppress the development of the pathogen. When the disease is active, frequent foliar applications of small amounts of nutrients is necessary to keep the turfgrass from declining.
Additional maintenance practices that need to be addressed are thatch removal and reduction of soil compaction. Excessive thatch often causes the mower to sink which can result in scalping and reducing the amount of leaf tissue capable of photosynthesizing. Thatch and compacted soil prevent proper drainage, resulting in areas remaining excessively wet, depriving root systems of oxygen. Since recovery of Take-All-Root-Rot damaged turfgrass is often poor, complete renovation of the lawn may be necessary. Removal of all diseased tissue is advised.
As a native soil-inhabiting pathogen, Take-All-Root-Rot cannot be eliminated. However, suppression of the organism through physical removal followed by proper cultivation of the new sod is critical to the establishment of a new lawn. Turfgrass management practices, not chemicals, offer the best control of the disease.
It is acceptable to use fungicides on a preventative basis while rooting in the sod. Azoxystrobin, fenarimol, myclobutanil, propiconazole, pyraclostrobin, thiophate methyl, and triadimefon are all fungicides that can be utilized to prevent disease development while having to excessively irrigate newly laid sod. Ideally, the turf area should be mowed and irrigated prior to a fungicide application. Unless the product needs to be watered in, do not irrigate for at least 24 hours after a chemical treatment. Do not mow for at least 24 hours, to avoid removal of the product attached to the leaf blades.
With all the stresses that our lawns have experienced, it is very important to continue monitoring the turf and be cautious about the cultural practices being used. Take-All Root Rot is likely to flourish. Do not encourage its development. A pathology test with the University of Florida Laboratory can confirm the presence of the disease causing organism. Before resodding again, have the dying sod tested.
For information and the submission form go to:
Sample Submission Guide
For more information on the disease go to: