Just like people, plants have a few basic requirements in order to thrive. Along with fresh air, sunlight and water, plants need fertilizers. The air supplies oxygen, hydrogen and carbon and everything else comes from the soil.
Fertilizers are any material that provides any of the nutrients plants use as food.
When nature is allowed to follow its own course, plants will only grow where the nutrients are available. Since we would rather they do their best for us where we want them to grow, we apply additional fertilizer to the soil. To get an accurate evaluation of the nutritional needs of your soil, you will need to have a sample analyzed. The University provides this service. We have the form and bags for taking soil samples at our garden centers.