The RHS/Cardiff City Council joint event held in Bute Park at Cardiff Castle managed to attract 16,000 visitors, after poor weather in 2008 saw only 4,000 visitors at the show.
RHS shows development director Bob Sweet said: "The Cardiff show is small but beautifully formed. It's not all doom and gloom because people are interested in their gardens.
"Fruit and veg interest is incredible," he added.
Pre-sales for RHS shows were better than expected, although sponsorship was down, Sweet explained.
Solva Plants co-owner Julie Burton said: "A lot of people are staying in the UK and doing up their gardens. They will find £10 for a few plants although maybe not for the more expensive ones."