When it comes to choosing between fertilizers, there are two main choices on the market---natural and synthetic. A natural fertilizer is made of organic material. This is often accomplished by including items such as chicken feathers, manure, compost or even treated sludge from a sewer treatment plant. They can be purchased at a local lawn and garden shop, or even be made by landowners themselves.
Though the costs of some natural fertilizer products can rival, or even easily surpass, synthetics, there are cases where natural fertilizers can also be much cheaper. In some cases, investing a little time in composting may eliminate the need for other types of fertilizer.
Composting material, through grass clippings, weeds and even table scraps, provides organic material. This rich material can make a great natural fertilizer for many types of lawns. Further, when you use compost as fertilizer, this new fertilizer is available on nearly a monthly basis during the growing season (see reference 1).
Lawn fertilizers that come from synthetic sources are less likely to be biodegradable. In some cases, synthetic fertilizers are engineered to have a time release component. Thus, they are engineered to last a certain length of time no matter what. This can create problems, especially when it comes to fertilizer runoff.
The dead zone in the Gulf of Mexico is one of the dangers linked to fertilizer runoff. In this case, an area devoid of oxygen limits most life, because matter growing uninhibited in the Mississippi River due to fertilizer runoff reaches the ocean and dies. Though this is mainly due to fertilizers on a larger commercial scale, such as runoff from farms in the Midwest, reducing the synthetic fertilizers in lawns can only help the situation. Natural fertilizers biodegrade more efficiently.
Synthetic fertilizers are meant to promote the development and sustainability of life. Despite this fact, some fertilizers can be very harmful to humans and animals, especially if accidentally consumed in large amounts. Therefore, those with such fertilizers not only should be very careful about how they are applied, but where they are stored as well.
This is not generally a concern with natural lawn fertilizers (see reference 2). These fertilizers are coming from natural sources which are generally considered harmless to people. Still, while there is a greater likelihood of the product being harmless, it should never be assumed. Always follow label directions when using or storing any fertilizer product. This also applies to natural lawn fertilizers bought at stores.