When hay is baled and stored at high moisture levels, it can spontaneously combust, often resulting in a total loss of the crop and barn. These hay fires are responsible for hundreds of injuries and deaths each year.
To reduce the fire risk, bale and store hay only when its moisture content is less than 20 percent.
Hay fires generally occur within six weeks of baling, so it is crucial to monitor the temperature during this period. Drill 1/4-inch-wide holes deep into the hay. Tie a thermometer to a string and lower it into each hole, leaving it in place for 10 minutes to ensure an accurate reading.
Monitor hay at these key temperatures:• 150 degrees: Monitor temperature daily.
• 160 degrees: Monitor temperature every
four hours and inspect the stack. Never
walk on top of hay that is heating.
Call the fire department and wet the hay at these temperatures:
• 185 degrees: Flames likely will develop when the hay comes into contact with the air.
• 212 degrees: Hay is virtually certain to ignite.
Once it reaches 240 degrees, hay treated with certain preservatives emits a deadly hydrogen cyanide gas. Alert the fire department if treated hay reaches temperatures of 160 degrees or above, or if it is burning.
Get the most from your hay crop
Density, air temperature, humidity, and the amount of rainwater the hay absorbed after it was cut all play into how much time it takes a crop to dry. By managing these factors, you’ll protect against hay fires, improving the safety of your crop and your farm.
Help other farmers stay safe by sharing these tips.