The soaring cost of energy such as coal and gas has led some indoor vegetable growers to turn off their heaters.
Plants grow in a large greenhouse. File photo Photo: 123RF
Many indoor growing operations use gas or coal boilers to heat their glasshouses.
There has been a nationwide shortage of commercial carbon dioxide supplies and the cost of using coal is going up.
Leanne Roberts sits on the board of Vegetables New Zealand and is a covered crop grower in Marlborough.
She said energy prices were causing a lot of headaches for growers.
"I've heard of growers choosing to limit their heating, I've heard of growers choosing to shut their doors because of all of the changes, there's a lot of things that are causing a lot of uncertainty.
"We've also heard of people considering whole crop changes, so they're no longer going to be growing year round, they're looking at converting to seasonal crops that don't necessarily require heating. These are the massive decisions for people to make for the businesses."
Coal is getting harder to source and the cost of transporting it from the West Coast is only increasing, she said.
That alongside the cost of paying for coal emissions through the Emissions Trading Scheme has led Leanne Roberts to convert the coal fired boiler at her own business into a biomass one during the middle of winter.
"It's not ideal timing but we are very nervous about the supply of coal going into the future so we are going to work with a local arborist to use wood chips in the biomass boiler which is a waste product for them."
Roberts admitted the change was not one all growers could make.
"The new technologies are very, very expensive and for some growers particularly the small to medium ones depending on the site, the crop, there's lots of factors that go into the decision.
"It's a very, expensive solution that they're not necessarily going to get the return from and that's the reality."
Roberts said accessing gas supplies in the North Island had also become difficult.
"I know some growers have struggled to obtain gas through their traditional suppliers so they've had to be innovative with how they're accessing gas."
Growers making changes to when and what they grow due to the cost of heating could effect the supply of some vegetables, she said.