Types of Soil

• It is important to use the right soil mixture to have a successful box vegetable garden. There are three main components to soil: silt, clay and sand. The Vegetable Garden explains that "sandy soil is loose and helps the roots of plants breathe because it lets the air pass through easily. Clay soil absorbs water faster and keeps it inside longer... [and] silt is a fine mixture of sand and clay particles." Aim for 40 percent of the soil to be made up of sand, 40 percent of silt and around 20 percent of clay. The low percentage of clay is to ensure that water does not become trapped, which can lead to root choking and rotting.
  
  

Testing Soil

• If you use soil from the yard, it is a smart idea to test it before preparing a vegetable box with it. Simply form a small ball with the soil in your hand. If the soil crumbles very easily, it does not have enough clay and may be too sandy/silty. If the soil forms a hard, firm ball, the clay concentrations may be too high. Gardening centers can supply the needed soil supplements if it is lacking in one of the three components.
  
  

Preparing the Boxes

• After mixing the appropriate soil amount, add either compost or manure. This gives the soil an added boost in nutrients. Preparing a way for the water to drain from the soil is an essential step in vegetable box planting. If there is no drainage, the plants will quickly drown after the first heavy rain or extensive watering. Most containers come with drainage holes in the bottom, but some do not. If you make a vegetable box, leave the bottom open and place a mesh wire on the bottom for natural drainage. If you place the box above ground, make sure to install drainage holes similar to those in container pots.