Learn which plants thrive in your Hardiness Zone with our new interactive map!

Miracle-Gro's Effects on Humans

By Tanya Mozias Slavin ; Updated August 23, 2018
Miracle-Gro's Effects on Humans

Every gardener is familiar with Miracle-Gro, a plant food brand produced by Scotts Miracle-Gro Company. Adding Miracle-Gro to the soil of gardens and houseplants allows them to grow faster by assisting in the production of new plant cells. Horace Hagedorn and Otto Stern developed the original Miracle-Gro in the late 1940s, and it has become a household name and one of the most commonly used plant fertilizers.

Does Miracle-Gro Have any Long-Term Effects on Human Health?

There are no studies on the direct long-term effects of Miracle-Gro on humans. However, some of the key ingredients in this product have serious effects on the environment and possibly on human health.

Adverse Health Effects of Excess Nitrogen in the Environment

Nitrogen is one of the key ingredients in Miracle-Gro and in many other synthetic fertilizers. Since the 1950s, the use of nitrogen fertilizers increased five times in the United States and other developed countries. This widespread use of man-made nitrogen fertilizers has a profound effect on the environment and on human health.

Nitrate, the final breakdown product of nitrogen fertilizers, accumulates in soil and causes water pollution. Excess nitrate levels in soil produce plants that when consumed convert to toxic nitrites in the intestines.

Groundwater is the primary source of drinking water for most of the rural population of the United States. Ingestion of contaminated drinking water is responsible for a range of adverse health effects including methemoglobinemia (blue baby syndrome), various cancers, adverse reproductive outcomes (especially neural tube defects), diabetes and thyroid conditions.

In addition, excess use of synthetic fertilizers damages the natural makeup of soil in the long run. Plants that grow in such soil are deficient in iron, zinc, carotene, vitamin C, copper and protein.

Safety Information

Miracle-Gro contains urea, which can irritate the mouth, throat, esophagus and stomach. Swallowing it can cause nausea and vomiting. According to the Manufacturer's Safety Data Sheet for Miracle-Gro, if you accidentally swallow the product, immediately rinse the mouth out with water. Seek medical attention immediately. Call a doctor or poison control center and do not induce vomiting unless instructed to do so.

If Miracle-Gro powder or solution comes in contact with the eyes, immediately flush the eyes with plenty of water and continue flushing for 15 minutes. If irritation develops, get medical attention.

If a person accidentally inhales Miracle-Gro powder, take them outside or to a well-ventilated area and monitor for continued irritation. If coughing or additional problems persist, seek out medical help.