It should be added to the entire planting zone when renewing garden beds, but not to individual planting holes. Other pertinent information Fertilizer bags can be notoriously user-unfriendly. Often you will need to read the fine print on the back of the bag or label to find out all the contents, their form and amounts. It is important to calibrate you fertilizer spreader and the Extension Service has a bulletin that can help you do this. Sometimes, information on fertilizer settings can also be found on the fertilizer bag but might result in application of excessive fertilizer since, after all, manufacturers are motivated to sell fertilizer.
Fertilizers are food for the plant.
Lots of fertilizer will produce more flowers, fruits and vegetables. Surface application is best except on slopes where shallow injection is ok. Go to the Environmental Horticulture program page for further information.