The soil in your garden may not be perfect humus-rich loam, but that is all right. Even if your soil is poorly draining clay or quickly draining sand, you can improve your soil's conditions by mixing it with compost and other soils. If you are mixing sand with clay, be sure it is coarse grained sand and not fine grained sand, since the coarse grained sand drains better. Also be sure to decontaminate any soil before you mix it together.
Boil a large pot of water and pour it over the soil you will be mixing with the already existing soil. This servers to kill any diseases living in it.
Remove any rocks or weeds from the existing soil with the rake if you are mixing soil into the ground.
Add 2 parts coarse sand to every 1 part clay soil. Add 5 to 8 inches of compost to the area as well. If you are mixing it in a pot and not the ground, add the materials to the pot.
Work the sand, clay and compost into the soil with the cultivator to a depth of 6 to 10 inches. Dig the cultivator into the ground and pull back to mix the soils together. Repeat this process until the soils and compost are mixed well, leaving the soil moist and crumbly.
If using a pot, mix the sand, clay and compost together in the pot with a hand cultivator or your hands. The mixture should be moist and slightly crumbly when you are finished.
Add a 2 to 3 inch layer of topsoil over the mixed soil, if desired.