The Greenfingers’ Knockout Challenge was held on January 22 at the Crowne Plaza Heythrop Park in Oxfordshire.
Teams were made up of suppliers, GCA member retailers and garden centres.
Deborah Skillicorn, director of marketing and fundraising at Greenfingers, which creates gardens at children’s hospices nationwide, said: "I would like to say a huge ‘thank you’ to everyone who took part and to the people who supported it.
"The Knockout Challenge was based on the BBC1 game show ‘It’s a Knockout’. There were colourful inflatables, costumes, props, water and bubbles. Eight teams of eight people took part.
"The money was raised through entry fees. The GCA and its members’ support is greatly appreciated."
The winning team was made up of garden centre owners and staff from garden centres in the GCA’s Wales and West region.
GCA chairman Peter Burks said: "We are still counting the money raised for Greenfingers from the Knockout Challenge, but we are very pleased with the amount that has been collected so far. It was a fantastic day and everyone enjoyed themselves. Greenfingers is such a worthy cause."