One of the long list of logistical challenges facing the staff of the Aviva Stadium this weekend is to ensure the grass on the pitch grows 5 millimetres in the middle of the night.
That’s right - the ground-staff will be encouraging the grass to grow one fifth of an inch on what might be a chilly October night.
The grass needs to be 23mm for Ireland’s vital World Cup Group D qualifier with Moldova on Friday night and it has to be 28mm - or just over an inch - in time for Saturday’s Pro14 clash between Leinster and Munster on the same surface.
"By Saturday afternoon the grass growth would have been substantial," said the Aviva Stadium’s Head Groundsman, Majella Smyth.
"That’s thanks to the charge from our grow lights. These lighting rigs give artificial light to make the grass grow in the dark environment that we’ll be dealing with."
In the space of less than 20 hours this weekend the Aviva Stadium will host two massive games in two different sports attended by as many as 100,000 fans.
The staff and crews working at the Dublin 4 venue will have barely ten hours to turn around the stadium from an international football ground into a setting for provincial rugby.
It’s one of the biggest challenges that will have faced the Aviva Stadium since it was opened in 2010.
The last punters will leave the ground after 10.0pm on Friday following Ireland-Moldova, which kicks-off at 7.45.
The doors will open again at 11.0am on Saturday morning and the fans will start to filter in as the countdown begins for the rugby, which gets underway at 2.0pm.
"People will be working around the clock," said the Aviva Stadium’s Operations Co-ordinator, Daniel Wynne.
"A lot of planning has gone into this already. There is a huge amount to be done and we expect it to run with military precision. There is an additional challenge here for us because we’re moving from football to rugby."
One of the main tasks for Smyth and his ground-staff will be to get the pitch in shape again.
Hundreds, if not thousands, of kegs will have to be changed as the FAI and Pro14 have different deals with brewers
Ideally the playing surface should have several days to recover between games, but this won’t be possible this weekend.
Divots will have to be replaced, soccer markings washed off and new rugby markings laid down. The posts will have to be changed too, though this is apparently straightforward with sockets fitted into the pitch speeding up the process.
"There will be 19 staff working on the pitch turnaround," explained Smyth. "Ten staff repairing the pitch after the soccer match for divots, five removing the soccer markings, four erecting the rugby posts and we will work straight through to achieve this."
Pitch-side adverting and branding will have to be changed, kitchens, bars and shops will have to be restocked and even changes will have to be made in the media facilities because different broadcasters hold the rights to each game.
Speaking of bars, hundreds, if not thousands, of kegs will have to be changed as the FAI and Pro14 have different deals with brewers, meaning that different beers will be served for each match.
Then there’s the cleaning, which is one of the biggest jobs and will go on through the night, with all of the stands, corporate and hospitality areas having to be scrubbed so they will be as spotless for the second set of fans as they were for the first.
Lansdowne Road holds 51,700 supporters for rugby games and that drops to 50,000 for soccer because buffer zones between rival fans have to be provided.
Both games are heading rapidly towards sell-outs so the 100,000 barrier could well be broken in less than 24 hours.
This isn’t the first time that there’s been such a quick turnaround at a sporting venue in Dublin. In 2009 Croke Park hosted a World Cup play-off game between Ireland and France and then an Ireland-Australia rugby autumn international with 150,000 fans attending the games.
The Aviva Stadium’s Wynne added: "One thing we have to be very aware of is that we are in a residential area and that we have a lot of local residents so we need to keep light and noise throughout the night to the minimum."
Apart, of course, from the glare of the grow lights and the deafening sound of grass growing one-fifth of an inch.
