Ask the Experts

In an effort to provide additional assistance to NIAAA members concerning the maintenance of athletic fields, athletic directors will now have the opportunity to ask the experts. Questions pertaining to their athletic fields will be assigned to the appropriate NIAAA Sports Turf Committee Member or NIAAA Sports Turf Education Sponsor. An attempt to answer all questions will be made. Some will be included in the “Ask the Experts Section in each issue of IAA.

The expertise represented by the NIAAA Sports Turf Committee and its sponsors is vast. The areas for which the committee has expertise include 1) design and construction, 2) renovation, 3) soil analysis, 4) irrigation, 5) drainage, 6) mowing, 7) core aerification, 8) top dressing, 9) seeding, 10) fertilizing, 11) sand-based fields, 12) herbicide and pesticides, 13) equipment, 14) field marking materials, 15) stenciling, 16) landscaping, 17) artificial turf, 18) field usage, 19) sport specific issues, e.g., baseball mound maintenance, use of infield mixes, laying out fields, artificial turf, etc.,

The NIAAA Sports Turf Committee and NIAAA Sports Turf Education Sponsors have provided questions and answers for this, the first “Ask the Experts” Section. NIAAA members may submit questions. Please email your questions to Brad Rumble, NIAAA Sports Turf Committee Liaison at Please include your city and state, because in some cases, geographic conditions may have a bearing on the answer. Please include your phone number, as well.

I live in the Northeast – New England area; which height should I mow my grass at to prepare use? We play at 2”, but heard that we should let it go during summer months and then start reducing mow height. Which is correct?

I think cool season grasses should be between 1 ¾” and 2 ¼” in the northeast so you are at about the perfect height. I am, however, against increasing the height of the grass during the heat of the summer then mowing it shorter at the end of summer. Grass does not like to be stressed by mowing and when you have to lower the height, especially during late summer when it is still recovering from the heat of the season, you stress it even more. You are better off choosing a height and, more importantly, mowing often enough so you never cut off more than 1/3 of the length of the grass at any one time. That might mean mowing two, maybe three times a week during the spring and fall but only once a week during the hotter days of summer when it grows slower. An don’t forget that with good mowing techniques you can make your fields look great!!

I have a native soil field, new soil was introduced to help level low spots – now I have different color grasses – what do I do to fix it?

What you are describing is a very common result of renovating sections of any natural grass athletic field. It is possible there were some different varieties of grass seeds in the soil brought in or there are some annual grasses growing in the new areas. The issue is more likely the result of the seed used to fill in the renovated areas being of a different cultivar(Bluegrass, Rye Grass, Zoysia, Bermuda, etc) or blend of cultivars from the remainder of the field turf grass. In addition to cultivar differences there can be different Genetic Color, Leaf Texture, Density, Growth Habit, and Uniformity within specific cultivars.

The best corrective action is to find one grass seed blend or cultivar that best suits the need your field has. In determining what cultivar best suits you location, you need to consider watering capability, use schedule, maintenance practices, playability, safety and coloration you like. Once you find the blend or cultivar that best suits your field, over- seeding is the best way to improve the consistency of coloration. This process might take a couple of years, dependent on the number of opportunities you have to aerate and over-seed the entire field in the growing season. Long term using the same blend or cultivars of seed will allow you to continue to fill in low areas or damaged areas and maintain the coloration, growth habits, and color consistency you are looking for. If you have the ground available, I also suggest you plant a nursery plot of the same blend or cultivar. This allows you to have the same turf available on site for emergency needs where you can cut up a piece as sod and repair damaged areas of the field quickly.

What is the best way to determine when an athletic field is ready for use by athletic teams after the snow has completely melted? Is there away to make the snow melt more quickly on athletic fields?

Snow is fun, why remove it?! Seriously the best way to remove snow is to let it melt naturally, you could provide a light dusting (no more than one application of 46-0-0 urea at the rate of up to one and one quarter pounds of actual nitrogen per thousand) of urea but it is hardly cost effective. If the ground were frozen beneath the snow you could set a plow with a rubber tip or as Steve LeGros over at UNH has done mount a piece of PVC on the bottom of the plow and push the snow off the field (ensure that plow is on float and set approximately one inch above actual surface). Another way of removing snow is a power broom mounted on the front of a tractor – the same rules apply for tracking and Nylon bristles will cause less damage to the turf. If the field is not frozen you run extreme risk of rutting the field with tire tracks – that would be a costly mistake and ruin the integrity of the surface not to mention the subsurface compaction that it would cause.

How soon can you get on the field? Hopefully you have “wet rules” established for your fields during active play season when periods rain occur. If not they should read as follows; Wet Rule, no admittance to field for a scheduled or unscheduled event when field is too wet to support play without altering the integrity of the field surface. Field will be inspected by the field manager and coach, both will make an informed decision based on conditions including event schedule pressure. Only after they have determined that the field can be used without causing damage to the surface will a permit or permission granted.

From a technical perspective it must dry to the point where you can walk on the field without creating any depressions in the soil or causing a sponge effect (that’s where water surfaces when pressure is applied to the surface) – I know that this may take awhile in the spring and when the weather breaks everyone is eager to get on the fields but a couple of days of patience will pay big dividends in maintain the integrity of your field surface. In the spring fields will dry quicker as the days get longer and the wind blows, a little patience will go a long way in preserving the integrity of your fields.

For a quick tour at UNH drop an email to Steve LeGros ( ) grounds / athletic field manager at UNH and he can further discuss with you some field management techniques.

My athletic fields have developed depressions in various areas creating an uneven surface. Some are so big that they appear as large puddles when it rains. Our grounds crew leader insists on just throwing soil on top and then seeding. The result is always the same. The soil shifts, thus creating unstable footing for the players. What can be done to correct this problem? Hopefully, your answer will help me convince my grounds crew that they have taken the wrong approach.

Whereas the approach taken by your grounds crew is wrong, you should at least be thankful they are trying. Listed below is a step-by-step plan that you can share with your grounds crew to resolve your problem.

  1. Ensure that any soil that will be used matches what is on the field in question. Filling with sand or soils that are not similar will cause long-term problems.
  2. Determine if seed or sod will be used, because this will have an impact on the amount of soil required to obtain a level grade. For sod, when step six is completed, it will be ¾” below grade (assuming you are using new sod). For seed it should be at grade.
  3. When making a repair remove any vegetation that encroaches the area of repair – if sod can be salvaged protect it by setting it on wet burlap. Also set it in the order that it came out, sort of like a puzzle with the pieces numbered. This will aid in keeping the soil/root zone moist and will aid in setting it back in place.
  4. Locate a matching or similar type soil –that is debris free and not to moist to work with.
  5. Scarify with a heavy rake or lightly till existing soil but no more than an inch.
  6. Add new soil (if depression requires less than six inches of soil add new soil all at one time – if more than six inches add in four inch intervals but blend each level) to a level approximately 20% above desired finished grade. Lightly blend imported soil with existing soil ensuring a bond of the two. Tamp or roll soil, then grade to desired level – use of straight edge is very helpful to ensure accurate grade with surrounding edges. If area is large than eight to ten feet accuracy will be difficult to obtain and total grading of the field might be a future consideration.
  7. When grade is attained lightly scarify soil and prepare as a seed or sod bed. Install the seed / sod and keep moist.

I think your grounds crew will find these steps to be highly effective in resolving the problem.

How can individuals who work or participate in outdoor activities lessen their risk of being struck by lightning?

The most dangerous myth about a thunderstorm is that seeking shelter is not necessary until lightning is seen or thunder is heard. However, this practice could prove fatal. The truth is that a typical lightning stroke can extend 6-10 miles, and is often too far to either see lightning or hear thunder. By the time a thunder storm can be seen or heard, the window of time to reach safety has past by as much as 10-15 minutes.

There are 200 deaths and over 1000 serious injuries caused by thunderstorms each year. Over 30% of all lightning victims are struck before a storm arrives. In fact, approximately three-quarters of all lightning fatalities occur under blue skies and no visible or audible signs of nearby storms, i.e., the “bolt from the blue.” Nearly 60% are struck after a storm has passed.

The keys to avoiding dangerous situations are to be aware of storms far in advance, so as not to be struck by lightning strokes from the storm’s leading edge and to stay indoors until the storm’s trailing edge has passed. Obtaining accurate information about the presence of storm activity, along with the critical factors of estimated time of arrival and the time to safely clear are needed to make the right decisions regarding safety of those individuals who work or play outside, such as field managers, coaches and participants in activities and athletics.

Thanks to new technology, this is now possible with the Thunderbolt, a handheld storm detector that is manufactured by Spectrum Electronics Inc., of Tampa, Florida. The Thunderbolt is capable of detecting thunderstorm activity from 75 miles away, and then continuously displays warning information on its LCD screen. The distance to the storm activity, storm intensity information, as well as approach speed, and the estimated time the storm will arrive at the user’s location are all monitored continuously with 15-second updates. Flashing alarm and audible alarm provide warnings in a variety of operating environments.

Brad Rumble, NIAAA Sports Turf Committee Liaison

Now that winter is approaching, what things should be considered regarding an upgraded irrigation system for spring?

We all know how difficult it is to justify a renovated irrigation system, much less a new one! With different types of equipment, being manufactured today, any AD can achieve healthy, safe, aesthetically pleasing turf while saving water and MONEY!

This is the perfect time to attend an educational turfgrass and irrigation-related conference, which typically take place from October to March in every state. The Irrigation Association ( has an excellent educational program/ conference offered in November. Not only will various irrigation courses be taught, but the expo is a showplace for all new and innovative types of equipment.

Listed below are a few updated and efficient water-saving products and special features to look for:

  • Pressure regulating valves and sprinklers. Reduce high pressures and eliminate misting from the sprinklers. Pressure is the number one biggest variable in an irrigation system.
  • Adjustable arc sprinklers. Eliminate overspray on hardscapes and areas where irrigation is not needed.
  • Drain check valves in sprinklers. Stops low-head drainage after sprinkler system has shut off. This is due to elevation change in the sprinkler pipes.
  • Rubber covers and higher pop-ups on sprinklers. Safety first! Small exposed covers that are made out of durable rubber offer maximum protection during play on a field. With more and more water restrictions taking place, turf grasses are being mowed at a taller height. It is very important to make sure the sprinkler pops up high enough to shoot over the grass blades and there is no deflection.
  • Battery operated controllers. When there is no electricity available, but water is near, irrigation systems can now be used with a simple, easy to operate battery-operated controller.
  • Rain and other weather shut-off devices. When it is raining, the irrigation system should not be operating and these devices automatically shutoff the controller when the weather dictates it to.
  • Remote controls for your automatic timer. Check irrigation heads and complete system with the ease of a remote control. This makes a job easy for one person instead of two!

Other system considerations could be:

  • What type of pipe is currently installed? If it is old, possibly galvanized, the interior of the pipe has probably corroded and needs to be replaced.
  • What is the main water source? Are there alternatives such as recycled, gray, new city tap and/ or a well with a pump?
  • Is there enough pressure to run larger turf sprinklers? If not, check with a local irrigation distributor and they can help determine what size pump you might need.
  • Is there a current as-built design of the existing field? If not, think about hiring a professional contractor or designer to help create a plan that shows where everything is located. If you are looking at a new system, make sure this is one requirement that is not overlooked by the contractor.
  • With new systems, determine what areas on your fields are priorities for irrigation. Make sure the sprinklers are designed and installed within these specific areas, separately from the other locations. Then, if there are any water shortages, the critical areas can still be watered (middle of football field, etc).
  • If you are unsure if your existing system is operating efficiently, check with local distributors for professional references of contractors who can conduct a water audit and show you hard data regarding uniformity and efficiency.

As we all know, water is our most valuable resource, and needs to be managed properly in order to enhance risk minimization and aesthetics. Take advantage of this season to become more educated on basic hydraulics, system components, installation techniques and overall irrigation maintenance techniques.

Is it okay to use a Seed-a-vator on our soccer/lacrosse and baseball fields monthly?

A Seed-a-vator should only be used in the overseeding process. I would not recommend using this machine early in the spring prior to growth, unless one is overseeding. A Seed-a-vator has thin slicing tines that will cut the rhizomes of bluegrass plants at a time when they cannot heal because the plants are still inactive. Once active growth has started, this process will actually propagate the bluegrass plant and help increase the density of the turf. Use this machine when the grass is actively growing, make two passes at a 45-degree angle and set the machine approximately 1/4″ below the soil surface to ensure that you get down through any thatch layer that may exist.

This machine will only provide surface disruption and will not penetrate the soil profile to any great depth. Thus, it will not provide a real source of aeration.

Disturbing the soil surface can break the pre-emergent herbicide barrier causing what would have been dormant weed seeds to be exposed. As a result, the weed seeds will germinate causing weed encroachment.

What height of cut should athletic fields be mowed?

The answer depends on the type of grass you have and your region of the country. Cool season athletic turf (bluegrass, ryegrass, and tall fescue) should be mowed at a height between 1 ½” and 2 ½.” Many schools feel that longer is better and keep the heights of 3” plus. On the contrary, cool season grasses develop much denser root systems at lower heights – down to about 1 ½” (depending upon the species and varieties selected). The downside of shorter grass is that divots are more visible and shorter grass must be mowed more frequently.

When outsourcing field management, what should one look for in a company to ensure that quality service is provided by the vendor?

  1. First and foremost, develop tight specifications (or have an expert develop them for you) that clearly define the services you want provided. By services we mean, frequency of cut, height of cut, fertilization, irrigation management, aeration, topdressing, overseeding provision of equipment, and other ancillary tasks that must be performed such as field set up – take down, stadium cleaning etc.
  2. You should define the credentials of the company providing the service, such as; who will be on site; their qualifications; how reputable the company is; is a Certified Sports Field Managers on staff; do they currently provide athletic field management services for other districts (universities or parks). Is training provided to their employees and is it documented? Will the employees be in uniform; are background checks conducted? What alliances have been formed with other grounds organizations such as suppliers or equipment manufactures? Can they perform other services for your district that would help offset the cost of just fieldwork?
  3. Qualify the equipment. How new is it? Will it provide quality service and not track or leak onto your fields?
  4. Is the price fair? Compare apples to apples. This is why specifications are so important. All contractors must line item cost to demonstrate that they understand what it is you are requesting and will hold them accountable to.

What is important in selecting a fertilizer?

The short answer is that there really isn’t a short answer. If cost per bag is the only consideration given, then the results may be disappointing or misdirected. One has to consider what type of controlled-release nitrogen to use as well as how much. This will likely vary depending upon the season and geographical location. Is phosphorus required or perhaps, banned from use? What form of potash is desired and how much? Are micronutrients needed? A soil test is the best way to get answers to these questions.
Then, talk to a reliable source to interpret the test and make a wise product choice.

What is the recommended slope of a baseball/softball outfield?

Slope required for a ball field is related to surface drainage. Most native soils do not absorb significant amounts of water; therefore surface water is removed from the playing surface by the field crown. The steeper the crown, the quicker the water is removed. The optimum slope for most types of soil types is 1.5% – 2.0%. This is in direct conflict of the incorrect perception that baseball outfields should be flat. Flat outfields actually promote drainage and turf problems.

What is the recommended soil and amendment composition for Baseball skin and softball infields?

Most of the “skinned” portions of baseball and softball fields constructed today are comprised of sand, silt and clay, however, the type of sand and the proportions of each component are important to ensure a good playing surface. Typically 60% sand, 15% silt and 25% clay makes a good, workable skin and is a good place to start but I’ve seen some variations that work fine also. The minimum depth of this base should be four inches but six inches will prevent any chance of scarifying into the subsoil. There are various sizes of sand gradations and most will work fairly well but make sure there are not any particle sizes or pebbles larger than 1/8” and make sure the sand has not been contaminated with other soil. Another way to make sure you know what you are getting is to find a soil formulator that has provided skinned area materials for softball and baseball, and go look at it both at the mixing site and at one of their customers’ fields. This may sound like a lot of work but remember over 90% of the game of softball is played on the skinned area and you want to make sure it is right.

Diamond Pro is vitrified clay used as a soil amendment to skinned areas to help with moisture management and to provide a more predictable ball bounce. Usually these products are spread evenly over the skinned area then tilled into the top two to three inches. The amount to use depends on the manufacturers’ recommendations but three tons tilled in should provide a good start. Then another ton can be “topdressed” over the surface and lightly scarified in so you end up with about an 1/8” on the surface.

The procedure or process should be to bring in your four to six inches of base. Grade it evenly to a good rough grade (+ or – 1”) then compact lightly and till in your soil amendment. Laser grade and compact with a heavy roller to ensure there will be no future settling and add your topdressing followed by a light dragging in using a nail drag or spring tine grooming machine.

One thing to remember is that skinned areas will evolve over time as you add soil amendments and drying agents. The key is to get to know your skinned area and how to maintain it under the various weather conditions you will face.

A good reference for construction and maintenance of athletic fields is: SPORTS FIELDS – A Manual For Design, Construction and Maintenance, by Jim Puhalla, Jeff Krans, and Mike Goatley, Sleeping Bear Press, ISBN 1-57504-070-0.

Why is it important to winterize your irrigation system and what is the best means to accomplish this?

Winterizing prevents damage that results when water remains in your pipes and system controls during the winter months. There are two basic methods of winterizing an irrigation system; 1) gravity and 2) “blowing out.” The latter is the preferred process because it guarantees all elimination of water in the system.

Gravity systems require in-line manual drain valves at all low points and a drain sump (gravel bed) at each of these points must be installed. “Blowing out” requires the use of an air compressor (100 – 500 CFM) to push the water through the lines and components, thus eliminating the water from the system. Do not exceed 80 psi when blowing out the water! The compressor hose is connected to a winterization point (quick coupler, hose or special valve) and then air is slowly allowed to flow into the system. Winterization should also include removing or wrapping the back flow device. Turn the controller to “off”, “Rain Off”, or “Stop” and unplug and remove main electrical wires. When blowing out, do not:

  • Exceed 80 psi
  • Stand over component parts
  • Leave compressor unattended
  • Blow out system through a pump
  • Leave manual drain valves open

What is the best way to care for turf in drought conditions?

Depending on the area of the country you are in, cool season grasses perform best between 60-70 degrees and warm season grasses perform best at temperatures above 80 degrees. Turf grasses can usually survive four-five weeks in dormant stage with minimal damage. There are four keys to managing turf in drought conditions:

  1. Proper irrigation practices are critical during times of drought. Water should be applied from 5:00 a.m.-9:00 a.m. and approximately one inch per week is enough to keep the crown, rhizomes and roots hydrated properly.
  2. Mowing properly, during the cool part of the day, sharp blades, and removing no more than 1/3 of the leaf blade, will help control stress of the plant.
  3. Proper fertilization will help the turf become more stress resistant and allow for quicker recovery. Potassium is a critical element to make the plants more stress, insect, and disease resistant. Using slow release fertilizers helps keep the plants growing during drought conditions.
  4. Applying wetting agents will allow for more efficient use of the available water by reducing surface tension allowing water to spread quicker and more evenly in the root zone areas. Co-Polymer gels can be used for water retention.

Utilizing the above practices will allow you to minimize turf damage from drought conditions.

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