As we walk into a tiny bare room, down in the basement of Summerhall, we're greeted by Frank and welcomed to the inaugural meeting of his Amateur Gardening Appreciation Society. Frank is in his early seventies; he's decided to move into a care home – where we find ourselves now – because he's finding it difficult to live on his own without his wife. And so begins a poignant story of the reality of old age, of love for gardening, and of memory.

Crawford Logan looks the part as Frank, with his red galluses and tartan tie tucked into his trousers. He starts talking about soil; it's the most important thing to keep in mind, obviously, but he soon veers off into memories of the past and of his wife Joan. They had no children, and were tied to each other by their intense love for gardening: he had his rocks, stones and soil, while she cared more about the birds and flowers and colours.

As the narrative progresses, it is evident that the ending won't be happy – and Logan's performance holds his audience's attention, steady and intense, until the final moments. Many sub-themes arise: the joys of working with one’s hands, the cyclical nature of birds and flowers, the passage of time, the importance of memories, and, of course, old age.

The scenes are chopped up, rudely and unevenly, by the interruptions of the care home nurse. It's a very deft performance by Nicola Roy: she comes and goes, bustling on about pills and plants and the TV. Her presence helps keep the situation real, and brings home the fact that a care home is always very communal. You are never really left to your own devices, no matter how intimate your conversations.

One thing to be aware of. Logan is very much in character, so you do have to enjoy listening to old people talk. The first 20 minutes of the script rambles on, jumping between small anecdotes; I had the strange sensation that he'd told me the same stories before, like an ageing grandparent who you dare not interrupt. And it's easy to tune out from topics involving soil and water – especially in this post-lunch slot.

Despite that note of caution, this show is a beautiful reminder of how our lives change with time, and of the things that keep us going through the setbacks. As Frank puts it: "Like the soil, we are not quite as simple as that. Memories, connections to one another. Isn’t that what we are really all made of?"