Does Antifreeze Affect Plant Growth?

Antifreeze is used to protect vehicles from the negative effects of temperature extremes, including sudden frosts and heat waves. Sometimes known as "coolant," antifreeze is bright green or yellow in color. Its purpose is to change the freezing and boiling temperature points of water to help keep vehicle radiators from either freezing or overheating. Vehicle antifreeze is made from one of two primary chemical compounds: Ethylene glycol (EG) or propylene glycol (PG). Both can cause damage to animals, plants and grass, though in different ways. If antifreeze leaks from your car or truck and comes into contact with plants, grass or soil, your lawn and garden could be adversely affected.

potted plants in the greenhouse
credit: erwo1/iStock/GettyImages
Does Antifreeze Affect Plant Growth?

Types of Antifreeze

Antifreeze is generally one of two types. Ethylene glycol mixtures have been around longer, while propylene glycol variants are newer.

As the market for antifreeze increased, it also became apparent that different regions needed different formulations. As a result, there are many different formulations and varieties available for purchase. However, regardless of the region, antifreeze is still either based on ethylene glycol or propylene glycol formulations.

Propylene glycol antifreeze is similar in chemical structure to ethylene glycol and has the same effects on temperature points. Although it is less toxic to the environment and plants, propylene glycol still incorporates potentially dangerous heavy metals that can harm pets and humans.

Plant Antifreeze

Not to be confused with ethylene or propylene glycol antifreeze formulations, there is also a product known as "plant antifreeze." Plant antifreeze generally comes in a spray formula, and is designed specifically to help plants survive winter weather and overnight frosts.

Plant antifreeze works by lowering the freezing temperature point of the plant's internal tissue moisture. The beneficial effects of plant antifreeze last about four to six weeks. Of course, this kind of antifreeze won't hurt your plants or limit their growth potential.

Toxicity of Antifreeze

When ethylene glycol antifreeze comes into contact with grass or plants, it can be devastating to the health of the soil and the plants or lawn grown in that soil. Put simply, ethylene glycol can kill grass and plants, which is one reason why homeowners should take care to prevent leakage or spills in the driveway or on streets adjacent to the lot.

Trees and plants are also susceptible to serious damage from ethylene glycol antifreeze. The chemical solution can slow down growth by up to 80 percent.

Contact with other chemicals in antifreeze is also damaging to plants and soil. Over time, antifreeze breaks down into corrosive acids, becoming contaminated with heavy metals, fuel and other substances from the vehicle's engine. Substances including tin, copper, zinc, lead and benzene leak from the vehicle and can likewise cause growth delays and plant death.

Research has shown that, when treated with an ethylene glycol solution, plant seedlings took eight days longer to bloom. They also showed a greater degree of pollen sterility, and yielded fewer seeds.

In humans and animals, ethylene glycol antifreeze may cause severe damage, including damage to the brain, kidneys and heart.

The Effect of Propylene Antifreeze on Grass and Plants

Although not as toxic to plants and organisms as ethylene glycol antifreeze, propylene glycol vapor has been shown to be toxic to corn and soybeans. In scientific experiments, the vaporous gas caused chlorosis, which is an abnormal loss of the usual green color of leaves, which then turned into necrosis – or cellular death.

In humans and animals, propylene glycol can damage the central nervous system.

Safety Guidelines in Cleaning Up Antifreeze Spills

Because antifreeze can be so toxic and harmful to plants, animals and humans, it's important to follow proper safety guidelines in cleaning up and disposing of it.

Wear appropriate protective gear, including gloves to prevent absorption by the skin and a face mask to reduce inhalation of antifreeze fumes. Don't allow pets or children near the spill.

You can use absorbent pads to soak up the spilled antifreeze. Make sure you dispose of any used materials in full compliance with hazardous waste disposal regulations. Don't use a hose to wash away antifreeze. This may dilute the substance but won't prevent damage to plants, lawns and animals.