The difference between heavily advertised brands like Miracle-Gro and the generic "balanced" fertilizer is often unclear and garden centers often feature an incredible array of choices. All fertilizers are described in terms of the major nutrients that plants take from the soil as they grow. Minor or micro nutrients are seldom included in all-purpose or balanced fertilizers but are added to custom mixes based on individual soil tests.
Miracle-Gro makes a variety of fertilizers, several of which have been used in home gardens since 1951. The company began with one product and today makes specialized products that include several balanced fertilizers and potting soils. Many other companies also make balanced fertilizers. A balanced fertilizer contains equal portions of nitrogen, phosphorus and potassium--the three major renewable nutrients that are represented by the N-P-K numbers displayed prominently on the package label.
Most Miracle-Gro products are composed of green to greenish-blue water-soluble granules that the gardener dissolves in water, making enough for a watering can or in a mixing device that fits on the end of a hose. Balanced fertilizers for home use are produced in granular or liquid form. Granular forms often come with coatings that control the release of nitrogen and are called slow-release fertilizers, a feature that makes nutrients available over a long period of time and controls fertilizer run-off.
Balanced fertilizers feature N-P-K numbers like 8-8-8, 10-10-10 or 13-13-13. All-purpose Miracle-Gro contains twice as much phosphate--the element used to produce blooms--as nitrogen or potassium; it is rated 15-30-15. Miracle-Gro's product for azaleas and rhododendrons, originally labeled fro acid-loving plants, is labeled 30-10-10. Miracle-Gro also produces several granular Shake n' Feed Continuous Release products; the general-purpose Shake n' Feed is rated 10-10-10.
A balanced fertilizer is recommended for use on lawns and in gardens to replace nutrients taken from the soil to maintain soil fertility. Miracle-Gro's differing formulations target specific aspects of plant growth such as leaf, flower or fruit development.
Unless a soil test has established the need for an uneven N-P-K, the balanced generic product is what agricultural extension experts recommend. Miracle-Gro's packaging and marketing expenses are passed along to the consumer, but unless the home garden is very large, the difference in cost is offset by Miracle-Gro's compact size and ease of use and storage. On the other hand, some generic balanced products may contain organic components like blood or bone meal, manure and soybean oil; Miracle-Gro is a chemical formulation.