On a beautifully sunny Sunday morning, we were allowed access to a secret garden: Edgbaston Guinea Gardens Allotments.

As the last remaining example of groups of detached rented gardens which once encircled 18th century Birmingham, this magical green space is a really special part of Birmingham's history. Every garden is private – with many hidden behind mysterious doors – and each previously had a bothy where gardeners could have a cuppa and a rest.

New GoodGymer Steve walked from Moseley, while Laura ran from Stirchley and I strolled over from Cannon Hill Park, meaning everyone was nicely warmed up to join the gardening party. One of the allotments is used by the Garden Club at the nearby Edgbaston High School for Girls, where the pupils learn about horticulture and develop woodworking skills – and of course eat the fruits of their labour.

Sabreena and Steve from the allotments put us to work transferring matured compost into sacks ready to use on the Edgbaston High School plot, via sieves to remove sticks and other materials. It was a hard job that would have taken one person most of a day, but between the three of us we made a sizeable dent in a couple of hours. Meanwhile, the school pupils, parents and teachers got stuck in on the vegetable plots.

After refreshments and cakes (made by the talented pupils) in the bothy – reconstructed on the site of the original, after all these one-room huts were demolished in the last century – we managed to fill another sack of compost before finishing up. Thanks to everyone from Guinea Gardens for having us!