At the HTA Garden Futures dinner, he said: "Are we inspiring with the unattainable? With fashion or cookery, you're presenting people with something they can go out and buy, but no-one will recreate Diarmuid Gavin's Sky Garden.
"The public are passionate about gardening but spend relatively little on it. People talk about the garden as being the room outside but is that true? They see their garden as an assault course and think that looking after it is all about digging. Gardening isn't sexy enough."
McIndoe added: "The industry is having a tougher time trading than most of us would let on. But gardeners are by nature optimistic."