Fungus spores, logs of wood and plenty of patience.

That's all it takes to transform felled trees into a commercial shitake mushroom crop.

South west Victorian farmer Rob Wertheimer, from Colac, has spent five years producing a high-end, boutique crop to sell in restaurants.

"Traditionally shitake grow on oak logs, which is what the 'shi' is," he said.

"'Shi' means a type of Japanese oak and 'take' is mushrooms so literally they are oak mushrooms.

"We don't have a big supply of oak in the area so we've experimented with different types of eucalypts.

"I think they would grow on a very wide range but it depends what you've got in the area."

Mr Wertheimer says his current crop of shitakes come from blue gum and sugar gum trees he harvested at Lismore, north of Colac.

He cuts the logs down, drills holes in them and injects pieces of dowel, that have been inoculated with shitake mushroom spores.

The logs will then sit for nine months in a moist environment to allow the spores to start to grow.

Mr Wertheimer says he dunks the logs in cold water, which signals to the log to start fruiting.

He says 10 days later the shitake harvest begins.

"It depends on the weather, but they will probably keep fruiting for about a week," Mr Wertheimer said.

"We harvest twice a day, every day for that week and then, when the log is not putting any more mushrooms out, they are re-stacked."

Shitake mushroom growing on a felled blue gum tree in Colac, in south west Victoria. ( Brett Worthington )

The vast majority of shitake mushrooms at the supermarket have grown on bags of sawdust.

Mr Wertheimer says sawdust shitakes are cheaper and quicker to grow.

He says his method of growing shitake relies on expensive manual labour, but says the costs are worth it, producing a tastier mushroom.

"At the moment we still haven't proved it as a commercially-viable business," Mr Wertheimer says.

"We've been doing it for five years, we're yet to make a profit, we've been plagued by all the sorts of problems you would expect in a start-up business and particularly a start-up business where there is no expertise in the country to call on, when you come across a problem.

"We're doing another inoculation this winter, we're combining all the knowledge that we've put together over the last five years... and we will look at the results after that."

Shitake mushrooms growing on blue gum logs at Colac in south west Victoria. ( Brett Worthington )

Mr Wertheimer says he enjoys eating shitakes in a range of dishes.

But he says his favourite is a simple shitake soup.

"[I] just tear them up, pour some boiling hot water over them and add some miso soup," he said.

"We'll drink that all day. It's absolutely fantastic... it's hard to get enough of them."

