Allotment and parks bodies are warning that cash-strapped councils must provide adequate support for allotment holders if they want them to run plots voluntarily.
Councils are devolving allotment management to their owners countrywide as part of the Government's "Big Society" regime, threatening to double or treble rents unless allotment-holders take on management.
The move is a result of local authorities looking to save money on allotments, which are typically subsidised by up to half of their running costs. But experts have warned that queue-jumping and disputes over evictions could make self-management difficult.
London Borough of Merton parks head Doug Napier has told borough allotment holders he has to cut staff by one third because of a 40 per cent budget cut in future years.
He said allotments needed large annual subsidies and that allotment rents would need to double to cover costs.
Meanwhile, Barnet council has tripled annual rent and is among many local authorities that are asking holders to take up management.
National Society of Allotment & Leisure Gardeners secretary Donna McDaid said: "It's not as straightforward as people would like to think."
She added: "Lots of local authorities are thinking this is an attractive way to get allotments off their hands. They are losing allotment officers and are asking sites to be self-managed.
"Allotment gardening is a recreational activity and should be subsidised in line with other recreational activity, such as sports centres."
National Allotment Gardens Trust chairman Neil Dixon said: "Most councils are moving that way now. They all would be willing to go that way if the plot holders would.
"Allotment holders taking over management is definitely the best thing that can happen.
"Councils are threatening to raise rents by as much as five or six times. The land doesn't cost a lot but the management costs a small fortune."
GREEN SPACE SECTOR VIEWS
- Dave Tibbatts, general manager, GreenSpace
"You need an open and fair waiting list and I'm not always entirely convinced that takes place under self-management. I feel that if all allotments move to self management that will mean a lot of allotment holders will not be as happy."
- Peter Neal, Consultant
"The cheap Big Society model is not a one-way street. If it is not a collaboration between local government and communities, it could be seen as offloading. We can probably run sites better than a council, but if we are liable for public indemnity legal issues people will be reluctant."