in the elements. A double skinned wall provides an air pocket of insulation that minimizes the temperature fluctuations and drying out of the soil in the garden bed. Sometimes raised bed gardens are covered with clear plastic to protect the crops from wind and strong rains. Pre-manufactured raised bed gardening boxes also exist. There are variants of wood, metal, stone and plastic. Benefits Raised beds produce a variety of benefits: they extend the planting season, they can reduce weeds if designed and planted properly, and they reduce the need to use poor native soil. Since the gardener does not walk on the raised beds, the soil is not compacted and the roots have an easier time growing. Waist-high raised beds enable the elderly and physically disabled to grow vegetables without having to bend over to tend them. Gallery Sunken gardens A waffle garden is the inverse of raised beds and is a gardening method by the Zuni people. In an arid climate, clay walls are built up around the planting area and plants are watered by filling the bed "cells". The term sunken garden usually refers to a formal traditional English garden where the garden is lower than the surrounding land, and may have multiple terraces around it and steps leading down to the garden. See also Hügelkultur: another type of raised bed Keyhole garden Kitchen garden Square foot gardening Therapeutic garden Waru WaruA traditional Quechua, pre-Inca system involving raised beds References Bibliography External links The Synergistic Garden—A video by Emilia Hazelip, which provides practical information on how to garden with raised beds. Appeal: Keyhole gardening saves lives in world's most eroded land Agricultural soil science Permaculture Types of garden