Fertilizer advertisements often depict a houseplant spilling lushly out of its pot. While this isn’t false advertising, it aims to capitalize on a common misunderstanding of plant physiology.
From a human perspective, the aboveground parts of a plant are the most important parts – often the only parts we think about at all. From a plant’s point of view, however, it’s the roots that matter most.
A plant’s root system can be as large as, or even larger than, the aboveground growth. A plant whose aboveground structures are larger than its pot obviously does not have this healthy ratio.
Yet it is exactly this pattern of growth that fertilizers are designed to encourage. The nitrogen in fertilizers stimulates plants to make more leaves and stems, neglecting their root development in the process. In the case of a lawn, this growth pattern often leaves the grass vulnerable to drought and insect attack – prompting the homeowner to add more water and pesticides, followed by more fertilizers, and so on.
All of these fertilizers do not stay on lawns, but make their way into the local water supply. The excess nitrogen makes water unsafe to drink, and contributes to algae blooms that make water unsafe to swim in. Contact with the toxins produced by algae blooms can produce unpleasant symptoms in people, including sore throat, difficulty breathing, hives, headaches, and vomiting. There is evidence that the toxins can be fatal to dogs.
Give your grass a chance to develop healthy structure, and it will need far less fertilizer to look great on the surface!