Be careful to avoid baling wet hay

Baling wet hay can create a significant fire risk

Feed Management
HAY FIRES: Farmers have been advised to ensure they avoid baling hay, which is too wet.

HAY FIRES: Farmers have been advised to ensure they avoid baling hay, which is too wet.


Take care to avoid baling hay that's too wet and check the stack regularly.


Agriculture Victoria has again reminded farmers to avoid baling hay, which is too wet, as it can create a significant fire risk.

Agriculture Victoria Northern Dairy manager Brett Davidson said wet hay could be caused by poor curing weather; nodes and seed heads still wrapped in the flag leaf sheath not being cured enough and incorrectly calibrated or improperly used moisture meters.

There was then the potential for forage being baled being two to five per cent higher in moisture content, than it should be for the type of bale being made.

Large rectangular bales need to be two per cent drier (12 - 14pc moisture) than large round bales (14 - 16pc) which themselves need to be two per cent drier than small square bales (16 - 18pc).

"This is due to their high density or large volume to surface area for the large rectangular and round bales," Mr Davidson said.

"Leaving wide windrows behind a mower-conditioner, tedding immediately after mowing (tedders will substantially speed up curing), and using a form of hay preservative will all increase the curing rate of hay.

"While these options add to the cost of hay making, it will be well worth the additional expense for high quality forage.

"Occasionally some of the hay will end up in the stack that has not been cured well enough."

Mr Davidson said it was vitally important to regularly monitor the stack from week one after baling, for signs of heating.

Monitoring could include:

  • dampness on the top of bales
  • steam rising from the haystack
  • moisture build-up on roofing iron or under tarped outside stack
  • unusual odours (e.g. pipe tobacco, caramel, burning, musty)
  • sometimes the stack may slump in places
  • corrosion on underside of tin roof.

Mr Davidson said unfortunately, much of the heating will occur in the stack centre, which is difficult to pick up.

A crowbar pushed into the stack as far as possible was one strategy that can be used to monitor heat.

"After a couple of hours, remove the crowbar and feel how hot it is," Mr Davidson said.

An approximate guide for a haystack temperature includes:

  • 50 degrees Can handle the bar without discomfort. Check temperature daily
  • 50 - 60 degrees Can handle the bar for a short time. Check temperature twice daily
  • 60 - 70 degrees Can touch bar only briefly. Check temperature every two hours. Move hay from top layers to improve air flow
  • 70 degrees Bar too hot to hold. Potential for fire. Avoid walking on top of stack. Put safety precautions in place. Call 000.

Mr Davidson said an alternative monitoring method could be achieved by using thermal couplings, which could be placed into various areas of the haystack at stacking and monitored simply and regularly.

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