A substantial portion of the fertilizers applied to lawns, gardens, and fields is washed or blown away before plants can take it up. When this material ends up in waterways, it can severely alter the balance of aquatic life, nutrient flow, and oxygen supply.

Even large bodies of water can be affected - there is a persistent, 5,000+ square mile dead zone in the Gulf of Mexico centered around the mouth of the Mississippi River, caused by fertilizer run-off from the fields and lawns of Midwestern America.


Fertilizer run-off can disrupt local biogeochemistry, causing a bloom of aquatic algae in nearby water bodies. When algae die, decomposition consumes all the dissolved oxygen in all or part of the water column and leads to an animal die-off. This is the process known as eutrophication.