Preventing hay shed fires

Why hay catches fire

Flooding increases the risk of hay shed fires, especially when hay gets wet. Wet hay can heat up and catch fire without a spark. This is called spontaneous combustion.

Hay with more than 16%-18% moisture can grow mould and heat up. 

If moisture rises above 25%, the risk of fire increases.

When hay reaches 55°C or more, it can release flammable gases. If oxygen is present, the gases may ignite.

What to do after flooding or heavy rain

Remove any hay that has been wet. This helps prevent fire and reduces damage to sheds and storage areas.

Do not feed water-damaged hay to livestock. It can cause serious health problems or death.

You can use damaged hay for composting. This is a safe way to recycle it into soil nutrients.

Learn more about on-farm composting flood spoilage.

How to reduce the risk of fire

• Check hay moisture often. Moisture above 20% is high risk.
• Store hay in a well-ventilated place so it can dry out.
• Make firebreaks around hay sheds to stop fires from spreading.
• Do not walk on heating hay. A hot centre can burn out and make the stack collapse.
• Be careful when moving hot bales. Adding oxygen can cause ignition.
• Make sure air can move around and through haystacks.
• Ensure hay is suitably cured before baling. 

Signs of rising heat in hay bales

• Bales with a caramel smell.
• Steam or smoke rising above hay.
• A metal rod inserted into a bale becomes warm after a few hours.

Understanding the risks of wet hay and taking simple steps can help protect your hay, livestock and infrastructure.

For more detailed advice, read the Hay shed fires Primefact.