On December 2, there were 10 crop fires near Horsham and all of them were sparked by headers.

The largest at Kalkee burnt 100 hectares of lentil crop and threatened nearby properties. Another three crop fires broke out in a similar area, all caused by headers.

Chief Officer, Euan Ferguson said while CFA understands the importance of cropping and harvesting, farmers need to be aware of their local conditions and have the correct equipment with them at all times.

"While harvesting can still go ahead during the Fire Danger Period, it's important farmers monitor the weather conditions closely throughout the day," he said.

"We encourage farmers to use on-site weather reading instruments to monitor the air temperature and relative humidity, average wind speed and gust strength. These can be really useful tools to assist farmers to identify when conditions become too risky to harvest.

"Farm machinery should be free from faults, fitted with a spark arrester and carry a knapsack pump or fire extinguisher.

"The most important thing you can do is take regular breaks to clear out grass, sticks and seeds that become caught in airflow vents, stone guards and bash plates. It's also important to regularly look behind you and know when to shut your machinery down - hot exhausts can easily start fires as can sparks when machinery hits stones."

Mr Ferguson said being extra cautious not only saves potentially tens of thousands of dollars in loss of assets, it also minimises the risk of unplanned fires starting which could risk lives and property.

"Safety should be your first priority. Extinguishers with the required nine-litre capacity should be fitted to every tractor or self-propelled header, and harvesters and other large machinery should also be equipped with a shovel," he said.

"If you haven't done it already, now is also a good time to check that your firefighting equipment is on hand and is in good working order."

Farmers should:

Make sure headers are checked and cleaned before starting work and repeat this every hour

Postpone unnecessary or non-essential work

Make sure they have firefighting equipment on hand and extinguishers fitted to the headers

Remain vigilant: look behind regularly to check for fires and take regular breaks to check for build-up of flammable materials in the machinery.

Check for straw of grass build up while harvesting

When carting hay, have a fire-resistant shield behind the exhaust.

Double check all spark arrestors

Avoid driving motorbikes through long, dry grass.

Leave the angle grinder in the cupboard on bad days

Farmers, contractors and landholders can find fire safety advice and guidelines online at cfa.vic.gov.au/farming or call 1800 240 667 to request a free copy of CFA's booklet On the Land.