The Beechgrove Garden’s Jim McColl is bowing out after more than four decades with the popular show.
McColl, 83, said he has not lost his passion for plants, but is quitting “just because I’m getting old”.
The green-fingered presenter will reveal his retirement on Thursday night’s edition of the gardening show.
He said: “It is time I retired, not because I have lost any interest in gardening or my enthusiasm for gardening, but just because I’m getting old.
“I’ll be 84 next birthday, so things are going wrong… in the sense that if I get down on my knees, I’m not sure I can get back up again.”
McColl, largely at the helm of The Beechgrove Garden since it began in 1978, revealed he has a “neuropathy thing” with his hands which has left him struggling to grip gardening tools.
He added: “One of the things you want to do when you are showing off on telly, is you want to do it properly.”
The Beechgrove Garden grew out of McColl’s participation in a Radio Scotland series The Scottish Garden.
Over the years he became known for his catchphrase “Every day’s a school day” while presenting the show.
Beechgrove producer Gwyneth Hardy said: “It’s the end of an era for Jim to be handing over the trowel.
“It’s been a big decision, not taken lightly for Jim as he is genuinely passionate about communicating his knowledge of gardening.
“He said to me recently that gardening is like breathing for him; it’s an everyday activity.
“I have worked with Jim for over 20 years and it has been a genuine privilege and an honour to work with a real Scottish cultural icon, who doesn’t see himself in that way.
“Even cultural icons have to retire sometime, and as Jim will be 84 on his next birthday then it’s not unreasonable that he’s thinking of no longer being on our screens.
“He really has given half a lifetime of service to Beechgrove and our loyal viewers.”
The show will continue with presenters Carole Baxter, George Anderson and Brian Cunningham, and newcomer Kirsty Wilson.
Baxter said: “I am going to miss Jim after working with him for all these years, but this is an appropriate time to celebrate his career.
“He is a great gardener and presenter. He shares his wealth of gardening knowledge in a way which engages people at all levels of gardening expertise from none to the professionals.”