If you are growing an annual vegetable garden, having sufficient fertility is of paramount importance. Most people know that plants need nitrogen, phosphorus, and potassium to grow. These elements are represented on fertilizer bags everywhere in percentage terms by the three numbers prominently displayed. For example a 24-18-12 fertilizer has 24% nitrogen, 18% phosphorus, and 12 percent potassium. This is also an example of a chemical fertilizer.
This I can tell simply because the percentages are too high for an organic fertilizer. An organic fertilizer rarely has more than a single digit percentage of any of the NPK ratio. There are also secondary elements and micronutrients that are often overlooked but still vital. For example, if you have a calcium deficiency you can apply all the NPK you want, but the plant will not be able to use it.