Winter pesticide storage
If you have liquid pesticides that need storing over the winter, make sure they don’t freeze.
Jan Hygnstrom works with pesticide safety at University of Nebraska Extension. She says the freezing point of many liquid pesticides is lower than 32-degrees due to the hydrocarbon solvents or inert ingredients. However, if they do freeze, this can happen.
"The active ingredients can separate from some of the inert ingredients. These would be solvents, or emulsifiers, different agents that are added to make the pesticide work better," says Hygnstrom. "Some of these emulsifiers or the inactive ingredients could crystalize or coagulate, and break down the original product, making it less effective."
If you thaw a pesticide out in the spring and see crystals in the liquid, don’t bother using it. Besides being ineffective, it could also clog up your sprayer.
The first rule of thumb when storing pesticides is to check the product label for storage recommendations and any warnings against freezing. Keep the chemicals locked up in a cool, well-ventilated place.
"One really big concern is about pets or animals, or children accidentally getting into or gaining access to pesticides. Have a secure area, don’t store them near any sparks or open flame, keep the containers very tightly closed," she says. "And use the original containers, again they have the label that has all that good information."
Hygnstrom recommends planning your pesticide purchases so everything is used up in one season. If you have to use a thawed out pesticide or herbicide in the spring, spray it in a small sample area to test it before you invest a lot of energy and time in an application.