Hay fires cost farmers thousands of dollars through lost revenues and replacement of buildings and feed. These losses can be practically eliminated through proper harvesting and storage.

Hay fires usually occur within six weeks of baling, but they may occur in hay several years old. Fires can occur in loose hay, small bales, round bales or stacks. They can occur inside or outside. Excessive moisture resulting in self-ignition is the most common cause of fires.

Hay fires can also result from causes other than spontaneous ignition. Some of these causes include lightning striking nearby trees or fences, arson, contact with electricity and sparks from cigarettes, welding or other nearby fires.

To prevent hay fires, the hay crop should be cured to the proper moisture content before baling. Moisture content is a key factor in microbial activity and the resulting heating. A moisture content of 15-18 percent at baling is recommended.

Weather conditions greatly influence the rate at which the crop dries. Ideal hay curing weather has less than 50 percent relative humidity and some wind. The moisture content of the hay will increase overnight when the air is humid, especially if there is dew or fog. Weather forecasts should be monitored closely before hay making operations are scheduled.

Conditioning equipment that crimps or rubs off the crop stems is helpful because it speeds the drying process. Using tedders (a tractor implement) or hay rakes to very gently fluff windrow may also speed the process of curing.

New hay that is stacked in the field or placed in a barn should be checked frequently for possible heating. At first, the new hay should be checked in the morning and the afternoon.

If no signs of abnormal heating are found, simply monitor the hay one to two times a day. If the temperature reaches 130 degrees, the hay should be moved to allow increased air circulation and cooling.

Hay that is to be stored uncovered outdoors should be formed into the tightest packages possible to resist penetration by rain. Unprotected bales or stacks should not be packed tightly against each other.

Instead, the bales should be located so that air can circulate freely. The bales should be protected from ground moisture, runoff and precipitation. A bed of gravel, old tires or pallets will keep the bales off the ground, and plastic tarps will shed precipitation.

If hay is stored inside a barn, the roof should be weather-tight. Likewise, the barn must have adequate drainage so water will not enter during storms. Hay may be at the proper moisture content when baled and stored, but moisture from a leaky roof can allow bacterial activity to increase and result in a fire.

For more information on forage production, Hall County Cooperative Extension offers a quarterly newsletter, Forage Facts. Call the extension office at 770-531-6988 to receive a free copy.