Police are calling for the public's help to solve the theft of a garlic crop worth up to $15,000 from a farm at Cockatoo, south-east of Melbourne.

In late November, approximately 400 kilograms of organic Australian and Italian garlic was stolen from a paddock.

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Senior Sergeant Carolyn Hill said the theft happened overnight.

"The previous evening [the grower] heard her dogs barking and looked out and didn't see anything.

"When she went to go through her property the next day she noticed the garlic crop had been harvested overnight.

"It probably took a few hours to harvest it and could have been one or two people who have actually committed the crime."

Senior Sergeant Hill said the crime was unusual and she had never heard of a garlic crop being stolen before.

"It doesn't mean it doesn't happen but [we have] certainly [had] no other reports in our area or adjoining districts."

Without public assistance, she said it would be impossible to track down the garlic and those responsible for stealing it.

"We'd certainly be encouraging anyone who has information to let us know, or if they're approached to buy quantities of garlic, that's probably our best option at this point in time," Senior Sergeant Hill said.

"The likely avenues that they might try to on-sell it will be through farmers markets, greengrocers or wholesalers.

"The other thing is the garlic could be replanted … so it could be to start a whole new crop."

In a Facebook post, garlic grower Leah McLeod said she was devastated but would continue her farming dream.

"Although this has been disheartening, I'm not giving up on my dream of becoming a successful farmer — I'll be back with gusto and garlic next year!"

Police said Ms McLeod was only one week away from harvesting the crop.

Growers offer to donate seeds

Victorian garlic grower Kirsten Jones is one of the producers who has offered to donate seed stock to Ms McLeod as she looks to rebuild her crop.

"I was fairly taken aback; I'd never heard of anyone stealing a crop, particularly a garlic crop," Mrs Jones said.

"She's not just lost that amount she's going to have to buy new seed stock next season."

Gippsland garlic grower Kirsten Jones has offered to donate some seed stock to Leah McLeod whose crop was stolen. ( ABC Rural: Isabella Pittaway )

Mrs Jones said it was likely whoever stole the garlic had knowledge of how it was grown.

"You have to know to harvest your garlic at exactly the right time, it can be even a matter of days, and it sounds like the thieves actually knew when to harvest the garlic," she said.

"That really surprises and dismays me.

"I think they must have been going past the crop and checking it out, perhaps driving past daily."

Garlic can retail for between $20 and $30 a kilogram and even more if it is organic.