Consider these 5 tips when storing pesticides on the farm

Just like a gallon of milk, pesticides have a shelf life that can be greatly impacted by storage conditions. How long a pesticide can last in storage depends on many factors, including its formulation, active ingredient(s), age, temperature, and whether it remained sealed or was opened.

"Farmers often have a significant investment tied up in crop-protection products sitting in the shed," said Fred Whitford, director of Purdue Pesticide Programs. "Taking a few simple steps can help make sure farmers get their money's worth from these products."

Here are five considerations farmers should keep in mind when storing pesticides:

Check the label

Pesticide storage requirements can vary widely. Reading the label details proper storage conditions for a particular pesticide. "Understanding how freezing and thawing impacts a product's efficiency is especially important," Whitford said. "Sometimes, once a product freezes, ingredients settle out and you can't get them mixed back into solution again."

The storage location should match the product storage requirements. For example, dry formulations should be stored in a low-moisture environment to avoid issues with clumping. It's also best to store dry products on shelves above liquid ones. 

Rotate old to front and new to back

Under the Federal Insecticide, Fungicide and Rodenticide Act (FIFRA), the EPA requires all pesticide products to meet active ingredient stability and product quality specifications. For most products, the formulation must remain stable for a minimum of two to three years under normal conditions.

One of the easiest things to make sure products remain effective during that time frame would be to label them with the year purchased. This is easily accomplished with a permanent marker to write the purchase date on each container or on the box in which they are packed. 

"Once the product is open, oxygen can reduce shelf life, so you want to use up those open products first," Whitford said. "Move the open and older product to the front and put the new products in the back."

Shake it up

After sitting for months in the barn or chemical storage room, some products may separate in their containers, lessening their effectiveness. Whitford said it's important to shake things up when spring arrives.

"Most products are in suspension, which means that over time they settle," he said. "Any time you have a product that’s just been sitting on a shelf, we would like for you to agitate before use to make sure the active and the inert ingredients are mixed together. This is true of large bulk tanks, mini-bulk containers, and 2.5-gallon jugs."

Inventory mangement

Whitford encourages farmers to have a limited inventory on hand. Buying in volume can lower purchase costs. However, buying more than a three-year supply for some products may not be prudent. Spending a little more up front to have the freshest product is worth considering as part of your purchasing decision.

“The less you have stored, the less product you will have to keep warm during the colder months,” reasons Whitford.  “If there is ever an emergency such as a fire, you would have a better chance of controlling the fire without causing environmental damage.”

Location, location, location

Whitford recommends having a separate location for pesticides away from farm equipment. 

“Typically, what we like to see is lower inventory and having a dedicated pesticide storage space that everyone knows,” says Whitford. “If a fire department shows up, they’ll have to make a decision on whether they’ll fight the fire or not. If it’s in one location away from the farm equipment, then maybe there are some options for the fire department to protect that equipment and your land.” 

For a deeper dive into strategies to maximize pesticide shelf life in storage, see Purdue’s publication, “Is this pesticide on my shelf still good?”