DIALING IN YOUR POST-GAME

After the big football or soccer game, a sports field manager has several things that they typically want to accomplish before heading home. There is a build-up, however short, towards the next game. To maximize the sports field performance, treatments need to be timely and done in the correct order. And while a good plan always helps, some of the work, by its nature, requires a read-and-react approach. This month’s tips are generally focused on natural grass playing surfaces. You can see my tips on artificial turf maintenance in my October 2015 edition of Tips from the Pros. For high-traffic natural turf fields used in fall sports like football and soccer, the mission is to smooth, re-grass and stabilize divots, scuffs, and skates before the next game or practice.

First up, alleviate grass stress.

Sometimes, the turf field may be on the dry side after a game, and you may need to get some recovery irrigation going. Rather than a deep irrigation, this lighter shot of water to alleviate some wilt should drain quickly and give you a workable tilth, or workability, to the soil. Doing heavy, physical work on a drought stressed grass is not advised. Before you can do that deeper irrigation, it may be best to delay and get some physical work done on the field before everything gets wet. In less fortunate situations, where the field is too wet after the game, you may want to stay off of it and let your drainage systems do their slow work for a day or two.

After cleaning up the team areas and any field equipment, run a field magnet over the surface if the game, game-entertainment or event would tend to drop metal objects. Some post-game field maintenance procedures use tractors, mowers or carts and can smash small debris left on the field after a game event. However you do it, cleaning the surface is always first. A good field magnet can not only reduce player hazards but also minimize flat tires on your field equipment.

After debris removal, vacuuming and/or sweeping the grass surface will stand-up any matted-over grass and remove loose plant material and loose soil debris from the surface. A vacuum may remove more than just a straight sweeper will, but you have to have some sort of sweeper on the vacuum to do the best work. A smaller walk-behind type leaf vacuum can work well on lighter and drier organic debris like plant bits, but may struggle to remove heavier, loose divots and soil. Vacuuming/sweeping are most successful when the field, especially the canopy level, is dry.

In the more heavily worn areas like between football hashes in the middle of the field or around soccer goal mouths, you may need to hand rake the area to really get a good, clean surface if the sweeper/vacuum isn’t able to get enough loose material up or the weight of the equipment will overly compact the worn area. Use a softer plastic broom-type rake for this and softer rubber (or equal) fingers or bristles on your vacuum/sweeper. You don’t want to do more damage than repair in cleaning your sports surface, be as gentle as possible.

In my experiences, loose material (plant and soil) will tend to build up over time and create a loose surface. Organics and loose soil build-up on the soil surface from cleated game or practice wear can impede air and water movement and can tend to “gunk-up” your repair seed, perhaps rotting it and diminishing existing turf re-growth potential. Moisture and oxygen is what you need, not gunked-up “turf-snot”. In higher level management turfs, like sand-based fields for example, keeping a clean surface may help minimize an organic build-up in the soil over time.

Divots:

Every divot is different, but generally fall into a few categories that determine their repair methods. After cleaning out any loose debris, look at the depth, width and length of the divot. Have the turfgrass crowns and other re-growth shoots been sheared off?

These more shallow divots are really better characterized as “scuffs” rather than divots and generally don’t need any seed in the topdressing, they will re-grow well, especially on grass species with spreading type growth habits, like mature Kentucky bluegrass or bermudagrass. Turfgrass species with a bunch-type of growth habit, like perennial ryegrass for example will more likely require some seed in the divot mix for quickest re-grassing of the divot, but not always. Just don’t overdo it with the seed on scuffs, you may be surprised to see a lot of live crowns and shoots. Even in a bunch-grass type divot like on a perennial ryegrass field may be more of a scuff than a divot. The general difference being the scuff still has intact and live plant growing points for regrowth, whereas a divot does not or has very few.

Large divots, more than a couple of inches, might better be repaired through a small and very thick sod patch which will provide instant surface stability, rather than with a divot mix. Large divots filled with your divot mix may not be stable enough before the next game or practice and create a loose spot in the field. Smaller, in-season sod patches in the field need to be much thicker than even typically harvested thick-cut sod rolls which can be up to 2 inches thick. I like to see at least 4 inch thick “plates” used. You need the extra weight for smaller patches, in my opinion.

Back to divot mix repair. Finish any post-game cultivation like aerification before you fill divots. Maybe you want to roll the surface to help smooth and firm-up the playing surface. Whatever physical work you want to do on the field after the game, get it done before divot filling. You don’t want to disturb the filled divot mix, you want to be able to ‘wet it and forget it’ for a couple of days. If you have time and crew, maybe consider poking a few holes with a rake-hoe (or equal) before filling divots to aid in drainage. Sometimes, the bottom of the divots can be “smeared-over” or otherwise compacted on the bottom, so some soil cultivation before divot mix is always a good idea if you can.

By now, you pre-germinated seed in your divot mix should be only a day or so away from popping. Fill some old paint buckets about half-way full with your final divot mix. (Full buckets of wet divot mix can get heavy). Divide up the number of buckets in half or quarters. This way, you will be sure to have enough for everything because you can ‘budget’ your buckets of divots mix.

Smaller impressions and wrinkles, like those made with hell-digs from play, can be carefully pressed back into place. Use a small fork-rake and treat the impression similar to a golf green ball-mark repair.

Divot Mix Recipes:

If you play golf at various golf courses, you will see different divot mix recipes at almost every golf course. There is no one best mix for all situations, but with a little experimentation and reason, you can keep things simple and successful. For a refresher in the aspects of seed germination and development, see my September 2015 blog on overseeding. Basically, a good in-season divot mix will contain pre-germinated grass seed of an appropriate species mixed with some type of “water-holding” soil amendment like some of the inorganic ceramics (think cat litter highly engineered for horticultural use), soil appropriate to the underlying base soil, or possibly an appropriate organic amendment. The idea is to have something filling the divot that keeps moisture around the seed, drains well and works well with underlying base soil, and provides for a stable surface appropriate for play once the seed pops. It won’t gunk up, even when wet, and it will hold moisture around the pre-germinated seed to aid in quick germination. This can be key in back-to-back game weeks on your field. You don’t want to over-irrigate the entire playing surface during game week just to keep the seed in your divots fills moist.

For divot mixes in-season, I like to see about a 25%-50% volume of seed approximately. This is well beyond textbook bare soil seeding or even overseeding rates. With traffic, the colder, shorter days of fall and a short window to germinate, successful germination rates are lower and sometimes a crowded, juvenile divot repair for a few weeks until it thins out isn’t a bad thing to get through the fall sports season.

Work your way methodically over the area, minding your bucket and your budget. This could be something like 10 yards at a time down a football field. Fill each divot to just below grade and gently level with your shoe/foot. You might even task one crew member with a watering can to give each newly filled divot a squirt of water after planting.

Turf Tips 101: More Divot Repair Tips

Tactics start with your base grass. Generally, we use spreading type grasses on turf fields. In the southern, warmer climates this usually means a hybrid bermudagrass variety of some type. Kentucky bluegrass is the most popular grass in the cooler, northern climates. Bermudagrass spreads by underground rhizomes and stolons that run along the surface. Kentucky bluegrass spreads with underground rhizomes only. So the first thing to do when inspecting a post-game divot is to determine the re-growth potential. Are there stolons and/or rhizomes in the divot that could act as growing points for repair? Some divots, there won’t be anything there really for regrowth from rhizomes or stolons and you have to add some seed to get speedy recovery. It’s basically a grass cover game.

Often by October we are using a cool-season grass to repair divots, even on a bermudagrass field. Bermudagrass seed (if available) is rarely if ever used in divot mix. During the summer, active growing period, a well-established stand of bermudagrass will self-repair from re-growth. Kentucky bluegrass will recover from regrowth better in the spring and fall months typically. Many southern bermudagrass fields are overseeded with perennial ryegrass in the fall months to provide green grass cover within the soon-to-be-dormant bermudagrass. As such, perennial ryegrass (PR) is typically used in divot mixes. Kentucky bluegrass (KB) fields will typically be overseeded with perennial ryegrass also, however some field managers may want to keep their divot mix strictly KB in order to keep a pure stand. Perennial ryegrass will mix in and can even take over a KB turfgrass stand with continual PR overseeding. If the divot is shallow, and there are healthy growing points visible (rhizomes and/or stolons), you might just fill the divot slightly with a dry divot mix (no seed) to bring things back to grade and let regrowth do your divot repair. You kind of evaluate each divot as you go along.

Since we often have only one week or less to pop the seed in our divot mix and fill grass cover in last week’s divots, pre-germinating the divot mix seed can offer several advantages. By soaking the seed bag in water for about 24 hours before mixing with your amendment, you can gain a few to several days jump on your germination time. Depending on your soil temperatures and assuming adequate moisture, pre-germinated PR seed in a divot mix can germinate in as little as 3-4 days after planting and fill the divot by the next game.

Rule #1: Don’t overfill your divots. You want to fill the divot with divot-mix to just below grade. Keep in mind that as the seed germinates and absorbs water, it will tend to expand and swell a bit. Depending on the type of amendment you use, if any, further swelling can occur once wetted. Filling the divot all the way to grade can cause a small hump in the surface after the seed pops. An over filled divot can also get scalped-off when mowing, minimizing the success of your divot fill work.

Finally, a light irrigation to wet the seed, or a more deep irrigation to relieve drought on the field. It’s always a good idea to check you irrigation zones and heads are working correctly after the game with a quick irrigation zone check.

Resources of the Month

Pamela Sherratt, sports turf specialist at The Ohio State University wrote an excellent piece on divot repair a couple of years ago in SportsField Management Magazine.

Maybe consider purchasing a divot repair backpack?

End Quote

“The man who complains about the way the ball bounces is likely the one who dropped it” –Lou Holtz, Notre Dame football coach.

Posted October 19, 2021