The RHS and The Wildlife Trust have teamed up to launch Wild About Gardens Week, an initiative aiming to halt the decline of British wildlife.
The week, from 25 to 31 October, was prompted by the State of Nature report published in May and compiled by 25 wildlife organisations.
It found that 60 per cent of native species studied had declined in the last 50 years. One of the primary causes was loss of habitats such as wildflower meadows.
Talks and events will be held at the RHS gardens and Wildlife Trust visitor centres during the week. The RHS is also encouraging schools, gardening groups and their 145 partner gardens to run their own events and to log these on a special page on its website.
RHS horticulture advisor Helen Bostock said: "This should be a wake up call for all of us." She encouraged gardeners to do one thing to help, such as make a bird box or build a pond to help save declining species.
Free advice and resources are available on the Wild About Gardens website and through the RHS Advisory Service.
Natural England has separately produced a series of booklets telling people how to create wildlife-friendly gardens which are available on its website.