If you've got bad knees or back problems that make gardening difficult, a raised garden bed constructed of cinder blocks will eliminate the need to bend and stoop. Raised gardens aren't only easy to maintain, but they're a good way to garden where the soil is poor, and the cinder blocks will hold warmth, which gives plants a jump start in the spring. Although raised garden beds can be any size, beds that are two cinder blocks high are perfect for weeding and hoeing, and the perfect height for sitting on the edge.
Decide where you want to build your raised bed. Choose a place that with easy access to a water source, and keep in mind that most flowers and nearly all vegetables need plenty of sunshine. If you don't have a space in full sunshine, try to locate it where the plants will get morning sunshine. Avoid areas where the water pools after a rain, which indicates poor drainage.
Determine the size of the bed, keeping in mind that standard cinder blocks are 8x8x16 inches. Mark the area with stakes and string and remove the weeds from the marked area.
Dig down 6 inches, using the stakes and string as a guide. Make sure the bottom of the area is level, and then add 2 to 3 inches of gravel, which will create a solid foundation, and will also promote drainage.
Put the first layer of cinder blocks in place, with the holes facing up. Fill the holes with sand, rocks or gravel to give them extra stability. Once the first layer is finished, add the second layer. Be sure to start the second layer at the middle of a block. Staggering the layers will make them much stronger. Fill the holes with sand, rocks or gravel.
Fill the raised bed with good quality topsoil. Mix in at least a bag or two of organic material such as peat moss, compost, or well-rotted manure. If you can afford it, a couple of bags of perlite or vermiculite will keep the soil light and will promote drainage. The raised bed is now ready to plant.