Season

• Start the project when the weather warms in the late winter to early spring. Raised beds eliminate the importance of soil temperature, but early spring represents the arrival of warm air temperatures. This timing gives you the best possible range of planting choices.
  
  

Site

• Choose wide, flat sites with full sunshine and good air movement all day. Raised gardens eliminate the question of soil drainage, but flat sites provide easier construction, and vegetables and flowers do best with bright all-day sun. Mark out your bed sizes, from small 10-foot-square flowerbeds to large 25- to 30-foot-square vegetable gardens.
  
  

Building the Planter

• Dig a 3-inch trench around the borders of each garden, wide enough to accommodate your cinder blocks. These trenches make up your footers and provide security for the walls. Lay the first course of cinder blocks in the trench and stack second and third courses as desired. Stack the blocks in a staggered pattern so the seams offset for best security. End with walls at least 5 to 6 inches tall.
  
  

Soil and Fertilizer

• Mix soil for your garden with a combination of bagged garden soil, peat moss and organic compost. This soil mixture gives flowering and vegetable plants a loose, crumbly and nutritious base for growing. Look for inexpensive compost alternatives such as mushroom compost and rotted manure at local stables and mushroom farms. Organic matter such as compost and peat moss soaks up and holds moisture for plant use. Mix a starter fertilizer such as a 5-10-5 or 5-10-10 into the soil for rooting in flowering and vegetable plants.