The liquidation of the garden building company belonging to designer Trevor Tooth, whose designs show the influence of Gavin, has raised concerns that the garden design-and-build market may crash.
Speaking while judging Inchbald garden design students' work (see vox pop, p17), Gavin said: "There's been a boom time with lots of good designers coming through. That's to be celebrated but now there will be less work around. You do get that during times of uncertainty. Things need to quieten down a bit. People will be doing up their houses rather than building new properties or moving. That always happens in recession. But in terms of creating gardens we have been through a boom time and that will even out."
Gavin praised Inchbald student Odie Green as "someone whose work stopped me in my tracks".
Meanwhile, Gavin said he would not take the vacancy left by Monty Don on BBC Gardeners' World. He said: "I'm sure there's plenty of people who could fill that role. It's not really my type of thing. Gardeners' World is more gardening than garden design."
Gavin is opening a new office in Ireland and is working on a new book and a range of furniture with Habitat designer Terence Conran. He has just completed an Irish TV series on Irish genealogy and is about to start a garden design series for RTE with the working title of Diarmuid's Next Adventure.
He added that ITV primetime series Extreme Makeover Home Edition, with Gavin doing the gardening, has been dropped.