Use a fertilizer with the right combination of nutrients to supplement the specific deficiencies of your soil. There are advantages and disadvantages to both chemical and organic fertilizers. Chemical fertilizers work faster and can be applied in the balance of nutrients your garden or lawn needs. They are less expensive than commercial organic fertilizers and can be applied in concentrated amounts. However, they can be harmful to the environment, and can kill the plants if applied incorrectly.
Organic fertilizers are slower, but longer lasting than chemical fertilizers.
They actually build up the nutrients and earthworms in the soil so that fertilizing won't be needed as much in the future. However, they don't contain the balanced mix of nutrients that chemicals do. There is another environmental problem which comes from the use of any fertilizer. That's the potential for causing pollution by running off into lakes, streams and ground water. To avoid creating runoff, don't apply fertilizer just before a heavy rain because it'll wash it away.