In a lawn or field, the uppermost layer of soil is called topsoil. This is usually the top 2 to 10 inches of soil and contains more than 80% of the biotics that make the soil viable. Commercially, companies sell bags of differently formulated soil mixtures and label it as topsoil. A superior method is to analyze the soil, and add differing agents to produce highly fertile plant soil.
Left up to nature, topsoil may take tens of thousands of years to form an inch or two, but everything required to make rich, fertile planting soil is available through a compost heap or the local garden center.
Step 1 - Understand Basic Plant Nutrients
If you have a compost heap, sifted compost is one of the best sources of plant nutrients. If you do not have a compost heap, you will need to use fertilizer, either natural or commercial. An excellent natural fertilizer is horse manure that is high in nitrogen, an important plant nutrient. Chicken manure is actually one of the richest, but it must be mixed well in the soil to avoid "burning" the plants.
Step 2 - Gather Required Minerals
Plants require many different trace elements. Common metals such as copper, zinc, and iron are required, as well as such minerals as sulfur and chlorine. After a soil analysis, you will be able to pick up the plant food with the properly adjusted levels of necessary minerals. Using compost as fertilizer is usually sufficient for supplying the required nutrients.
Step 3 - Add Organic Matter
Organic matter is a term for decaying plant material. If you do not have compost heap to recycle household plant waste, soil treatments are available. In the compost heap, everything from the coffee ground to grass cuttings can be added to the heap, which is turned regularly to allow microorganisms and oxygen to cause organic decomposition.
Step 4 - Regulate Acidity
The acidity level in soil needs to be controlled. The pH level of your soil is arguably the most important factor that determines which plants will grow. If you are unsure of what the plant requirements will be, or wish to use the soil for a wide variety of plantings, use a soil pH range between 6.0 and 7.0, the most productive acidity range.
Step 5 - Add Oxygen
Using a pitchfork or potato rake, loosen the soil. In addition to allowing the roots to grow better, loosening the soil aerates it, mixing oxygen into the particulate matter. Heavily packed soil prevents the minerals from mixing into the soil and being transported to the roots of plants.
Step 6 - Water
The amount of moisture required in the soil will vary according to the types of plants it will be used with. A good rule of thumb is to squeeze a handful of the soil and release it. Ideally, the soil should clump, but not exude moisture when the hand is clenched.