Circular raised bed kitchen garden with central compost basket. A Keyhole Garden is a type of kitchen garden raised bed. The design - which looks like a keyhole from above - incorporates a central 'basket' where compostable waste is placed and greywater is poured. They have many different forms, and are especially useful in areas where good soil is scarce. They extend the growing season and supplement diets with added nutrition. The garden survives floods well and grows well in arid or rocky conditions as the raised bed holds moisture due to the high level of compost/humus in the garden.
The charity, Send a Cow, trains African groups in how to make them as part of their sustainable agriculture training.