What Plants Need from Soil

• Since plants are not mobile life forms, they are dependent on the soil they are rooted in and the amount of water they receive to supply the nutrients they need. Minerals dissolve in water, and water is leached from the soil through the plant's roots. Agro Services International lists the necessary minerals for healthy plant growth as molybdenum, nitrogen, copper, boron, phosphorus, zinc, potassium, manganese, calcium, iron, sulphur and magnesium. Chlorine, nickel, cobalt and silicon are also needed to a lesser degree. The roots of a plant absorb and filter out unnecessary -- and, to some extent, harmful -- materials. Soil must allow for air circulation and must provide an anchor for the plant's roots. Planting a plant in potting soil ensures it gets a balance of necessary minerals. Planting in your backyard dirt leaves the plant to the mercy of whatever minerals are present -- which may not be sufficient for healthy growth.
  
  

Dirt

• Dirt, or soil, is a product of a specific location. The Soil Science Education Home Page details how soil could be comprised of organic material, deposits from glaciers, volcanoes, wind, water or other components moved to that location. Dirt can be sandy, clay-based, silty or rich with organic matter from the decomposition of vegetation or animal life. Dirt is a random conglomerate of minerals based on the environment around it; depending on the location or type of plant, they may or may not be sufficient for healthy plant growth..
  
  

Potting Soil

• Potting soil is a prepared mixture of dirt, minerals and other additives proven to boast the growth of a plant. Peat moss is added to increase water retention. Pine bark, a byproduct from paper mills, is added to aid in retaining fertilizers and assist in air circulation. Materials such as vermiculite and perlite, both volcanic byproducts, are added to allow for air circulation. All of these additives help keep moisture and nutrients in and around the plant roots for a longer time span, which increases the roots' absorption of these nutrients, fostering healthy growth.
  
  

Adjusting Soil to a Plant's Needs

• If you plant in ordinary dirt rather than potting soil, fortify the dirt so the plant receives the necessary nutrients. Test the pH level of your soil to see if the soil is too acidic or alkaline. The North Carolina Department of Agriculture and Consumer Services suggests adding lime to acidic dirt. Dirt should test at a pH level of 6. Soil tests to check for the absence of minerals are available at garden centers. Once you know what your dirt needs, add fertilizer or missing minerals to the dirt. Some dirt, such as the clay-based type, are not hospitable to plants without extreme additives. Fertilizer packaging details the minerals in the mixture. Adjusting the soil through fertilizers and other additives in order to balance the minerals will help your plants grow faster.