You can build your own raised bed garden box and this is a good solution if you aren't sure of the soil in your yard or area. Compost and garden soil can be added so you can be sure of the purity if you want to grow vegetables and herbs and keep it organic.
Here are directions to build your own 6' by 4' by 1' box. You can change the sizes to suit your own space. The box will be filled with soil, peat and manure. You can add whatever compost you have managed to collect to the box if it's ready. Here are the materials for the box: You can get these at a local home supply store like Home Depot. The store personnel will cut the wood to size for you too.
Wood - Pine for a 4' by 6' raised bed garden box: Two 12' long by 1' wide planks Cost: about 12.00 each Cut one into 2 pieces for two 6 ' long sides Cut the other one into 8 ' long and then cut in half for two 4 ' long end pieces 4' piece of pine is left over Wood lath bundle of aspen for the lattice about 7.00 1 can of water based polyurethane - about 10.00 (to seal the wood) Let it dry for a few hours. 1 wide brush: about 4.00, hammer and nails Black plastic liner with holes punctured. You can use weed cloth as a substitute. Total cost of wood and supplies is about 50.00 plus sales tax.
Soil 16 bags of top soil 2 to 4 cubic foot bags of peat to be mixed in 2 bags of manure to be mixed in 1 black plastic tub for compost (To use kitchen scraps to add nutrients to the garden) Total cost about 55.00 And there you have it. It takes about a day to complete this project. Your urban garden box can be planted with anything from flowers to vegetables and herbs.