The former BBC Two controller criticised the amount of cooking and gardening shows, saying he wanted to see broadcasters "explore new things".
He said: "I think personally that we are doing too many actuality shows and, important though they are, there are other things like cooking, and so on, and gardening, which are very good and certainly should be on the network but we are doing rather too much of.
"We are also doing a lot of drama. And personally as an ex-channel 2 controller I think we are doing too much. Not because there's anything wrong with them in themselves, they are all absolutely excellent in their own way, but we are nudging out, and we are not exploring new things and new subjects enough."
His comments come as garden designer Jane Beedle finished as a runner-up in the last BBC series of 12m-viewer Great British Bake Off, which is moving to Channel Four.
Garden centres have cashed in on the baking trend, with many opening cookware departments and expanding afternoon tea offers.
Judge Mary Berry is sticking with the BBC and said this week she and Bake Off presenters Mel Giedroyc and Sue Perkins, who are also leaving the show, could even branch out into gardening TV.
Berry said of Perkins and Giedroyc: "We have made no decisions whatsoever, we haven’t actually all three got together, but we will do something because we’re good pals, and who knows what it would be?
"Well, it may not be baking, you never know, it could be gardening. I’m a very keen gardener you know."
Berry is at RHS Wisley Plant Centre on 29 October to sign new book Family Sunday Lunches. Berry is an RHS ambassador and regularly opens Wisley Plant Show and had a Harkness rose named after her this year. Her personal assistant Lucy Young is sister of RHS editor Chris Young
Garden TV confirmed for 2017 includes a seventh series of ITV's Love Your Garden.
Other TV planned for 2017 is Gardeners’ World 50th anniversary specials. Presenter Monty Don said on Twitter that programmes will be an hour long in 2017.
TV producer Betty TV has recently finished filming a new series called The Avant Gardener, with Alan Gardner, the designer and presenter from the 2015 Channel Four series The Autistic Gardener. The three x 60 minute series where Gardner makes over unloved gardens, produced by Betty TV, is likely to be broadcast in spring, though Channel 4 say it may be in the autumn of 2016.
Meanwhile, the Charlie Dimmock/Rich Brothers BBC1 daytime series is looking for applicants to have their gardens made over for a new series of Garden Rescue for 2017. The 20-episode first series aired on BBC1 this summer.
James Wong has filmed a BBC2 series for this autumn on how "plant science underpins food".