YARRA Valley orchardists are limited to covering 60 per cent of their trees in hail nets.

The Yarra Ranges Council policy exposed 40 per cent of Andrew and Wayne Rieschieck's orchard at Gruyere to marble-sized hailstones on Christmas Day.

Trees were stripped and fruit pounded, wiping out the brothers' profits this season.

Wayne said it took three years and $20,000 to get the permit to install the nets.

"We started putting the nets up and some people complained," he said.

"That's when council told us we had to get a permit. Apparently it upset the ballooners."

The planning policy demands: "Horticultural structures not exceed a site coverage of 60 per cent" in the green wedge zones where most of the valley's farmers operate.

Council planning spokeswoman Kim Marriott said the policy tried to balance the operation of horticultural industries with environmental and landscape values.

"Other factors would also be considered including an applicant's needs for the operation of their business," Ms Marriott said.

Victorian Farmers Federation horticulture group president Sue Finger said the restriction exposed orchardists and other Yarra Valley farmers to unacceptable risks.

Sam Violi, of Coldstream, said he had put off plans to cover his strawberries because of the policy and had lost 300,000 plants.

Agriculture Minister Peter Walsh will visit orchardists this week.