The return to a Sunday to Tuesday format is supported by trade bodies the Garden Centre Association (GCA), GIMA, Gardenex and Horticultural Trades Association.
Glee director Nick Davison said: "Focus groups, on-site and post-show research and retailer meetings have helped us identify a number of changes that could be made, the most obvious of these was the move back to a weekend opening - a simple change that offers significant potential for increasing vital visitor numbers.
"Added to this, there are also positive financial implications for exhibitors as contractors will now only be required to work one day over the weekend – a significant potential cost saving on stand build and set-up."
GCA interim chief executive Iain Wylie said: "The Glee team has been looking hard at ways of improving the show for those attending. When we asked our members the majority stated that in 2012 they attended on Monday and Tuesday but a significant number said they missed the opportunity to attend and bring their colleagues on Sunday. We passed this feedback to Glee and they have been able to bring about this change for 2013. It is important that the show adapts both to changing times and the needs of visitors. Glee is clearly listening to their views and making changes and innovations."
Hillview Garden Centre CEO Boyd Douglas Davies said: "I’m delighted to hear that Glee is looking to move the show back to a Sunday start in response to feedback from exhibitors and visitors. I think this will increase the number of visitors and improve the mood of anyone that hasn’t had to travel there in the Monday traffic! It will also free up a day during the week which is very valuable at that time of year."
Davison added: "Whilst there was some opinion that Glee should be reduced to a two day show, we have decided to maintain it as a three day show. The third day means that there is more flexibility for retailers to attend. A move to limit or reduce the amount of time available to retailers to visit Glee would undoubtedly have a detrimental effect on its success for both buyers and suppliers."
Davison said the content of the show will be completely revised.
One additional idea that is also being considered for 2014 and beyond is potentially moving Glee to new halls within the NEC.
Glee saw a drop in visitor numbers to 9,112 in 2012 from more than 11,000 in 2011.