The allotment, built on an old store yard by Enterprise staff, will be a resource for school children and will be open to the public.
The permanent allotment uses materials from the St James's Park allotment, which the Royal Parks closed in 2009 after four years to return the land to its original state.
Kensington Gardens manager Tom Jarvis said volunteers would maintain the area and explained that the allotment would provide an educational space in the gardens.
Education and community officer Nick Lane said rainwater collection, "minibeast" areas, beehive, fruit growing and composting were all educational resources.
He added that the Regent's Park environment and education centre would be next to be redeveloped as a community resource. The Royal Parks also maintains a vegetable patch at 10 Downing Street.