Turf Management

For those studying or interested in horticulture, a career as a grounds person may be an option. Management of turf on sports grounds, to ensure durability and rapid drainage as well as player safety, has become a specialised skill set. Football fields require different treatment to cricket pitches and the surface and subsoil structures are often very different. Perhaps there are things community sports grounds can learn where durability is required.  

Karl Johnson is the Turf Manager for H3, a division of the Hamilton City Council, which looks after FMG Stadium, Seddon Park, and several other sports grounds in the Hamilton area. FMG Stadium has hosted international rugby, the All Blacks, the Chiefs and Super Rugby games, the Warriors, the FIFA International Women’s Cup games and other significant events. Seddon Park is a boutique cricket ground hosting international, national and local matches.  

Karl served his apprenticeship as a groundskeeper in Canterbury and was later involved in creating cricket facilities at Lincoln. He came to Hamilton 20 years ago and has been very involved with developing and improving sports grounds in the city. He has also spent time helping to establish sound turf for cricket grounds in the United Arab Emirates and India, and rugby grounds in Japan and Samoa. 

Karl says that a lot of love and tender care goes into growing sports turf, but the techniques used differ widely with the requirements of the different sports codes. 

“For rugby these days the technology has changed. At FMG Stadium Waikato we have a hybrid turf system comprising a 300mm sand profile that has artificial fibres stitched into the surface by a massive ‘sewing machine’,” he says. 

“So, 5% of the surface is artificial fibres that go down 180mm and extend 20mm above. They stabilise the whole system, so you don't see scrums flicking turf out the back of the No.8’s feet as used to happen in the old days.” 

“There's no soil – it's all sand, and that's for drainage of the venue because most of our major rugby is played through the winter and we need to know the field will drain quickly.”. 

“Over time, organic matter builds up and we manage that pretty carefully with our turf practices throughout the year where we're scarifying and doing a little bit of coring. 

“Then every two years we actually remove all of the organic matter by stripping the surface layer back to the top of the fibres, and then we re-sow it.” 

Karl says that the turf structure for cricket grounds is quite different – the outfield has only 50mm of sand. 

“The cricket outfield is what we call a sand slit, a sand carpet turf surface, and every meter across the field there is a drain that moves rainwater away. We don't need the same stability that the rugby pitch does. However, we do use some stitching around the wicket block where bowlers are starting to take off on their delivery stride.” 

“The cricket wicket itself is constructed of 140mm of Patumahoe clay, a non-swelling clay, on top of a gravel drainage bed.  It's constructed pretty much like a road with a really hard compacted base topped with the compacted clay, and we grow grass on that.” 

“Each cricket pitch is 3m by 20m long, and we have ten pitches in the middle of Seddon Park. They can all be in different states depending on what games are coming up or what's being played at the time.” 

Getting grass to grow in sand or on clay is challenging, he says. Rye grass seed is sown, and water and nutrients applied. 

“We are fertilising all the time and use wetting agents to pull the moisture into the profile, which involves a lot of hand watering of the wicket block particularly over summer. 

“For the rugby pitch we have an automatic irrigation system that we use at night. We use moisture meters to determine how much water is lost during the day and then we replace that amount at night. Obviously being sand, the pitches do dry out pretty quickly over the summer, so we need to be accurate with our moisture management.”  

“In winter the drainage is very effective, and even after a few days of rain we can get back on the pitch pretty much straight away. We get quite a lot of comments from players that the ground drains extremely well and there’s no pooling of water on the surface.” 

Turf science 

“Some people think that we just sit on a mower and cut grass but there’s a lot of science to maintaining a good turf. We do many measurements and use a lot of tools. We measure:   

• the moisture content and infiltration rate of the turf 
• we do shear testing, which is how tough or how tight is the surface for a player to turn on their spikes 
• we're also measuring hardness, so if the ground does get too hard, which it does at times, we can go in with some machinery and soften up the profile.” 

While there are some similarities with pasture management Karl and his team are much more focused on getting and keeping the surface right rather than grass production. One thing they try to avoid is the build-up of organic matter in the sand, and this means removing all clippings from the surface.   

“There are certain times when the ryegrass is growing actively that we apply chemicals to slow down the leaf growth and to produce more and deeper roots – the deeper the roots are, the longer the turf will handle a hot weather or tough use.” 

As well as maintaining the turf at FMG Waikato Stadium and Seddon Park, Karl and his team of 12 also look after a number of training grounds including for The Chiefs.  

“It’s a large area to look after and a 7-day a week operation. When Super Rugby starts and cricket is still being played it’s full on and we are all flat out ensuring that our venues meet the expectations of our customers and clients,” he says.