I didn't know who he was so I can't point you in that direction but he seemed to be a contributor on Derek Mooney's radio programme so perhaps listeners to that will know who he was.
Anyway, whoever he was, he was really encouraging people to begin growing stuff and if I remember correctly he is opening his garden up for people to come and learn how to grow things. In particular he wanted to help people who had lost their jobs get involved with growing things and he wanted other people in other industries which are also hobbies (such as cooking) to get involved with teaching their skills.
He was really just saying all the different things you can grow in your garden and they had a big display of produce in the studio. If you click this link
you can view Friday's episode and the segment was around 50 minutes into the programme.... just after Gerald Keane's session of pontification...