The facility boasts hot and cold air heaters, paths containing 20 tonnes of gravel and large winding vents.
On a guided tour through the Iris and Rose gardens the Mayoress said: "It is an amazing privilege for all Londoners, including myself, to have these beautiful gardens to visit and enjoy.
"More green spaces means that we are better educated to make choices for a sustainable city. A food growing project at the Park, for example, will show how vegetables can be grown in even the smallest of spaces. Children will be a part of the process of planting organically and sustainably, and that is very promising."