To know what kind of soil you are working with you will want to have your soil tested. Your local County Cooperative Extension office should be able to supply you with information on soil testing in your area. Your soil sample will be sent to a laboratory and they will send you results that let you know what nutrients your soil needs and give advice on what steps should be taken in order to remedy this.
When you are adding nutrients to your soil after the soil test, you will only want to add nutrients that the test has deemed are needed. Adding things that are not needed can throw off the pH of your soil.
Fertilizer is also a needed additive to your soil, especially if you are growing a vegetable garden. Fertilizer will help your plants to produce much better fruits. There are many options in fertilizer in the categories of inorganic and organic.
If you want to fertilize your garden organically, one of the best ways is to create and use your own compost. For more information on composting check out these previous blogs:
Other organic fertilizers you can use in your soil are kelp, dried blood, cottonseed meal, cattle manure, horse manure, and chicken manure.
When using an inorganic fertilizer over a large area then you may want to look into using a broadcast spreader. This will help you even distribute the fertilizer over a large area.
During the growing season you may want to apply a side dressing (a boost of fertilizer) so that your plants continue to get the needed nutrients they need. To apply a side dressing you will want to make a 4 inch deep trench along one side of your plant row. Do not disturb the roots of the plants when you do this. Place your fertilizer into the 4 inch trench and cover it up with the removed soil. Watering your plants and rain will work your fertilizer into the soil so that it is easily used by your plants.