The call comes as a result of research which revealed local authorities in England spend an average of 1.36 per cent of their public health budget on mental health, despite having a remit to prevent both physical and mental health problems.
The latest statistics from The Department for Communities and Local Government (DCLG) show that in the current financial year English local authorities are spending £76m on increasing physical activity, £108m on anti-obesity measures, £160m on trying to stop people smoking and £671m on sexual health initiatives.
But a series of Freedom of Information requests by Mind revealed that less than £40m was spent on preventing mental health problems. This is not even reported separately in the DCLG public health figures but instead filed under ‘miscellaneous’.
This is despite an estimated cost of mental health problems being £100 billion each year through lost working days, benefits, lost tax revenue and the cost of treatment, and accounting for 23 per cent of the total burden of disease in the UK.
Mind chief executive Paul Farmer said that council spend on preventing mental illness was "unacceptably low".
"With demand for mental health services increasing, anti-depressants on the up and more people accessing talking therapies, we are beginning to see the scale of the unmet need for mental health services in England.
"As a society we must start looking at what we can do to help prevent people from developing mental health problems in the first place."
Mind has long promoted the value of accessing green space and ran the Lottery-funded Ecominds programme of 130 ecotherapy projects between 2009 and 2013, most of which have now secured funding from elsewhere to continue. In October last year Mind launched its Feel Better Outside, Feel Better Inside report which called on healthcare providers to pool budgets to jointly commission ecotherapy services.
Senior policy and campaigns officer Helen Undy said researchers found that some areas were interested in the use of ecotherapy – which ranges from gardening to exercise in urban green spaces or the countryside – but it was in "a handful of areas."
"We’re seeing a lot of interest in ecotherapy as an idea but not as a focused programme of public health," she said.
"Green space is important, we’ve seen evidence that living near green space is good for mental health and encourages people to get outdoors and take part in exercise which can have more benefits in promoting wellbeing and good mental health.
"One of the things that we’re calling for today is a clear national strategy setting out what local areas should be doing to promote good health and wellbeing. "
She said councils should collect decent data on these and invest based on that data to meet local needs.
Every year local authorities do a general needs assessment of their population in partnership with other agencies.
"We would see that as an opportunity, does the community have access to good quality green spaces and to ecotherapy?" she said.