Open Garden Squares Weekend is organised by the London Parks & Gardens Trust (LPGT), who work to protect and promote London's green open spaces.
Caroline Aldiss founded the event with the support of the London Parks and Gardens Trust and English Heritage. Around 40 private squares participated. (Further details ») For the first few years, the event was organised purely by an extremely committed group of volunteers and grew organically.
Thanks to development grants from the Heritage Lottery Fund and English Heritage, part-time paid staff were engaged to develop the reach and nature of the event. This investment saw the event grow steadily reaching a peak of 215 gardens in 2011. The Weekend was supported by organisations such as Loire Valley Wines, Transport for London, Capital Gardens and Evans Cycles.
The weekend continues to be run almost entirely by volunteers. A core team sources new gardens and manages the website, applications for the event, publicity/marketing and the production and distribution of the event guidebook, tickets and publicity materials. Most of the people involved in opening their gardens for OGSW do so voluntarily and there is also another pool of volunteers who spend about half a day welcoming visitors and checking/selling tickets in gardens which need extra help. Any surplus made from the event is divided between eligible participating gardens and the LGPT.