Ross Kurcab on latest field cover technology

The field manager’s dream cover is here and we are already seeing some interesting results in two of the tougher places to grow healthy grass late in the year: Minneapolis, MN and Nashville, TN. The Minnesota Viking are in their second season of use with their MacLeod Field Cover on one of the teams two natural grass training fields in Eden Prairie, MN. This past September, the Tennessee Titans bought a MacLeod inflatable field cover for their stadium field in Nashville, TN. I spoke with the two head field managers for the respective clubs about their experiences so far with this new technology. One is growing Kentucky bluegrass in the deep dark December cold of Minneapolis at about 45° north latitude. The other is trying to keep his game field of Bermudagrass green and resilient in December in North America’s turfgrass transition zone at 36.1° north latitude, where is it often said to be too hot for cool-season grasses and too cold for warm-season grasses.


A year ago TFP interviewed Grant Davisson, head turf manager for the Minnesota Vikings NFL football club, about his new inflatable, heated MacLeod field cover. This month, I caught up with Grant again to see how his first year went with the revolutionary field cover system and see what he has learned about it.

Grant and his turf team have one of the more challenging missions in sports turf. They maintain and prepare two natural grass training fields for the Vikings deep into the winter. The soil freezes in Minneapolis on December 8, on average, and the NFL season goes into January. They average about 54 inches of snowfall annually and neither of the two natural grass fields have a soil warming system. So the Vikings training facility is a great place to put the MacLeod field cover to the challenge and see if it can literally change the climate of a sports field at a fraction of the cost of a typical soil warming system.

Like any new technology, it takes some time to get to know the in’s an outs of a system. “It’s definitely easier” Grant says, “and we can get the field covered a lot faster now, as quickly as an hour to get inflation started. Inflating the cover takes about ½ hour, so about 1 ½ hours total. That’s with a team of 5 people”. The turf team began covering the field in October as needed and when I talked with Grant a week before Christmas, he said they have already extended the season for one of the outdoor, natural grass practice fields further than ever before. Typically by this late in the season, a frozen ground would force the team indoors, not their preference since they love Grant’s natural grass playing surfaces and they also have to play outdoors in the cold. “Right now, any turf that is not covered has a soil temperature of about 32°F (0°C) and under the MacLeod cover it’s about 48°F (8.9°C).” That’s pretty impressive considering that Minneapolis only gets about 8 ½ hours of day length this time of year and the grass needs all the sunlight it can get. The high-tech, translucent MacLeod material lets natural light through. The turf team can even work under it, something a soil warming system can’t claim

There are some great lessons to be learned growing Kentucky bluegrass fields so deep into winter, so far north. “One weird thing we learned was that we can get it so warm in there that if we need to drop the field cover for high winds or a storm, we can get temporary frost damaged leaf tips under it. It creates its own atmosphere.” This is a typical challenge in all natural turf systems designed to go deep into the winter. Weather its soil heating systems, field covers or both, anytime you delay, slow or prevent winter dormancy you will have to eventually expose the field to some cold temperatures this far north. Whether you use vented covers or an inflatable MacLeod cover with forced air warming, you will have to uncover the field for use or other reasons. Generally, the direct low temperature injury (DLTI) injury is only on the upper part of the leaf tip and will grow-and-mow out in about a week in most cases. “You have to break some rules with this thing”, Grant says “but the field is playing great. And we’ve found that grass is a very resilient plant. You can really abuse bluegrass and it will fight back”.

Another challenge in winter turf management in such a climate is managing leaf wetness. Any time you cover a field for more than 24 hours, whether your cover is inflated or not, you are prone to leaf wetness. As you warm the air around the turf during the daytime, you will increase its capacity to hold moisture. Soil outgassing and plant transpiration add moisture to the warmed air in the form of water vapor. When the air cools sufficiently at night, the moisture in the air around the plant loses some capacity to hold the moisture and condensation occurs on the leaf and also the underside of the cover which is exposed to the bitter cold air outside. The ingenious part of the MacLeod cover is that it is designed to be vented by simply opening panels and this can exchange drier air for the moist air. Yet even this unique new technology has limits in the coldest, darkest parts of the Minnesota winter in preventing some leaf wetness. So Grant and his team get in early to get the field uncovered for the many practice days, as early as 5 or 6 am, to allow the field to dry when leaf wetness occurs. In recent years, we have seen many top field managers using blowers and large kerosene-type heaters to do what the MacLeod field cover does automatically. The big differences include not blowing in exhaust, letting light in, and perhaps best of all a good night’s sleep not having to babysit the system all night as required when blowing large sideline heaters under a cover.

Grant and his team have also learned that you want to have good drainage around the perimeter of the field to handle the moisture that is sheeted off during rains. “If you think about it, we are covering almost two acres. During a rain, where does all that moisture go? When it snows, we need a plan to deal with the piles of snow on the sides.

Just a few of the things that a pioneer like Grant has learned in his first year of operation with the MacLeod field cover in the deep, dark cold of a Minnesota winter solstice. The benefits have been significant for the club and the team, allowing them to practice outdoors on a natural grass field deeper into the winter than was ever before possible in such a climate. “We just aerified today [December 15], is that not weird? I’ll topdress next week. The coach is happy, he gets to go [practice] outside.” With the first full season using the MacLeod cover not yet over, the numbers look good. “After summer training camp, we have a scheduled 63 regular-season practices and we have already had 43 outside to date. We hope to get to 50 before the season is over. Before we started using the MacLeod cover, we would usually only get around 38-39 practices outside” Grant tells TFP. “And it’s really the other grass areas that are not covered that often determine if we go inside or not, not the field covered with the MacLeod cover”. In other words, if the sled area is frozen hard, they may go inside even though the field under the cover is fine. “And sometimes if it is really windy and cold, coach likes to go inside”.

I asked Grant if he had any advice for someone that might consider getting an inflatable MacLeod cover. “Come up and take a look at it, you have to see how it works. In many ways, it’s the opposite of what I was used to with tarps. We plow snow off it different using brush-tipped plows instead of traditional plow tips and take the big snows off in stages, about every 2-3 inches. Grant says that the fabric is “super slick and easy to push snow off of”. “My best snow mover is a Sand-Pro”. Impressed with the ease of snow removal, he went on to say “On a stadium, I don’t think I’d ever have another tarp again. It’s that much easier to plow snow.” That is a strong thought from a guy in Minneapolis. “I know Terry got a MacLeod cover for their stadium this October [2015] and I talk with him a lot. It’s perfect for his stadium”. Terry is Terry Porch, the venerable head field manager for the Tennessee Titans of the NFL in Nashville. The Titans purchased a MacLeod inflatable cover for their natural grass game field at Nissan Stadium this past fall.

This fall, the Tennessee Titans of the NFL purchased their own MacLeod cover for their team’s home, Nissan Stadium in Nashville, TN. TFP caught up with Terry Porch, the Titans’ venerable head field manager, to get some of his initial impressions of the MacLeod cover. The Titans game field is a Bermudagrass surface set solidly in the North American Transition zone. As such, Terry and his turf team have typically had to struggle against a dormant surface by mid-fall. This year, after a lot of homework, the Titans decided to try the MacLeod cover to see if they could not only have an easy, all-purpose field cover, but more importantly extend the Bermudagrass growing season and improve field resilience until the end of the NFL season in Nashville. With only about 2 ½ months of experiences with the new cover, I asked Terry what his initial impressions were. “I love it. We’ve been getting down into the 30’s and even 20’s at night, but we’re still green. We usually go dormant sometime in October. But our game field hasn’t experienced a frost yet because of the MacLeod field cover. This year we’re still green when all the other Bermudagrasses around town are fully dormant. It’s not growing real fast, but it’s still green. I just put out some ryegrass last week and today it’s coming up green everywhere. I’m thinking this is going to look so nice”. Nissan stadium does not have a field heating system. But the forced-air warming of the MacLeod cover has acted as a far less expensive alternative for the Titans. The added bonuses are greenhouse warming, sunshine, sheeting off precipitation and the ability to work on the field under the inflated cover. “Tonight [Dec. 18] we’re forecasted to get down into the 20’s. But our game field hasn’t dropped below 50°F soil temperatures all year. At our [uncovered] practice fields, we’re at about 38-39°F soil temperatures.” Terry has seen some leaf wetness just like Grant up in Minnesota, as the nighttime lows have dropped late in the season. “It’s like a light dew, just like anything when you heat it, you have to watch your moisture closely.”

I asked Terry about how the field cover is for putting out and taking off the field. “It’s such an easy tarp to use. Actually, the up and the down time is about the same as your typical evergreen covers, but the nice thing with this cover is how easy it is to work with when it’s wet. You know how when your evergreen covers are wet they tend to kind of stick together and take more people to fold up? With this, it’s all automated. We literally do it with 4 people on game day, which allows the others to focus on setting the field behind them as they uncover it. It takes about 90 minutes max from deflation to complete removal and field set.” But partial removal takes far less time. “One Saturday I had the painting crew in working on the field. We just folded it off to one side. By not completely removing all the anchors and things, it only took us about 20 minutes. When we finished painting for the day, it was like 20-25 minutes to put it back on since we had 8 guys in that day.” But I wonder, what if high winds accompany the rains and you have to drop the cover? “We’ve had some high winds, you know, with the storms. But you just lay it down on the ground during the storm. Then after the rains are gone, it only takes like 30 minutes to pop it up and drain all the water off. Then you just lay it back down and roll it up. Piece of cake”.



I wondered if the team had noticed the difference this year. “You know, we’ve had comments about how nice the grass is looking this year, and how we haven’t had to dye it green this year. It’s been nice, we’ve been mowing all year. We had about ½ inch of rain before the Raiders game and even with rain during the game, we got a lot of good comments about how the field played. When we pulled the cover off, the field was dry and this helped it play much better by starting the game off dry instead of already wet. People love to watch us remove it from the field, it’s something they’ve never seen before”.

So what about the learning curve, how hard is it to learn how to best use the MacLeod cover? “They have great support” Terry says “You can even face-time for free with them over in England. It was good to talk with Grant up at the Vikings a lot. He was a big help.”

So there you have it. The inflatable MacLeod cover is no longer just a prototype. It’s passing the test at two of the most demanding venues in American sports and in two climates where it is very tough to grow heathy grass and deliver a resilient playing surface in the late fall and winter months. But beyond that, Grant and Terry are proving some of the other great advantages to owning a MacLeod field cover. It may be a much less expensive alternative to soil heating systems in colder climates. In any climate, it may well be the only cover you need. It has the water-proof, high tech material that allows sunshine through and is raised off the ground. It circulates air underneath which can be warmed up to 80°F (27°C) or more. It has an automated inflation and heating system which will automatically shut the system down and lay down the cover when certain wind or other thresholds have been met. What a great sleep aid for the field manager! It is very easy to use. It doesn’t completely close down your field for use or work when deployed.

A very big thank you to two world-class turf managers: Grant Davisson of the Minnesota Vikings and Terry Porch of the Tennessee Titans for taking time out of their crazy-busy schedules to catch us up to date on this important new sports field management technology.