Hay fires occur more often within 6 weeks of hay bailing than any other time. It is important to monitor hay bales daily during this time period. Use these tips to prevent hay fires.

  • Field stored bales should be stored in rows of north to south direction to maximize the sun exposure.
  • If you do not have a raised concrete pad, then utilize coarse stone on the ground under the bales to reduce moisture absorption.
  • Do not stack hay near public roads where discarded cigarettes can cause ignition.
  • Hay stored in barns should have openings at each end, whenever possible, to encourage cross ventilation to reduce moisture build up.
  • Remove and segregate any bales of hay that begin to collapse as this is a sign that these bales are subject to spontaneous combustion.
  • Keep hay stacks as small as possible with a 100-foot minimum separation between stacks.
  • Only purchase hay from reputable brokers. You want your broker to rely on your continued purchases so you form a partnership. Calls offering one time “cheap loads” from unknown brokers should be avoided.
  • Large bales are involved in more fires. Be extremely careful in putting up large bales. Probe all bales and remove any questionable bales.
  • Sniff test. Hay bales produce a particular odor prior to spontaneous combustion. This “composting odor” is a good warning signal. If this or a sweet caramel odor is present, remove bales to get to the center of the stack and probe bales.
  • Independently test to verify moisture and TDN. Small rectangular bales should have moisture content less than 20 percent and large rectangular or round bales should have moisture content below 18 percent.
  • High moisture hay should be probed every day for at least six weeks after bailing. Most fires occur during this period.
  • Commercial hay probes are good but are too short to probe the center of hay stacks. Use a 10-foot iron pipe with eight 0.375-inch holes drilled approximately 3-inches from one end, hammer that end together to form a sharp end. This will make a simple probe that can reach deep into the center of your stack. Lower a thermometer to the end of the probe with a piece of small wire. After 15 minutes retrieve the thermometer. If the temperature is nearly 150 degrees F the temperature will most likely continue to climb. Remove hay to provide circulation and cooling.
  • Temperatures above 170 degrees F indicate that a fire is imminent or already present somewhere in the bale. Take every precaution when handling hay at this temperature.

Source: Winton, Ireland, Strom and Green