After a particularly bitter winter, spring is taking its sweet time in arriving this year, and that’s causing nothing but headaches for maple syrup makers.

Across Canada, the usual mid-March maple syrup harvest appears to be on hold. That’s because the cold won’t let up and forecasters say they can’t see yet when it will.

Canada produces about 85 per cent of the world’s maple syrup, with a harvesting season that lasts only about six to eight weeks. But in order to get the sap to flow, syrup makers need days that go above freezing along with below-freezing night. And this year, Mother Nature is not co-operating.

At Fulton’s Pancake House and Sugar Bush in Pakenham, outside of Ottawa, most of the trees have been tapped but when those taps are turned on, the sap is too cold to run. Operator Scott Deugo there’s nothing to do but wait.

“It's like being at the starting line: you're all set, but you're still waiting for the guy to pull the trigger,” he tells CTV Ottawa.

The wait at Fulton’s is expected to get longer; temperatures are expected to be in the negative double digits for most of the week. When it’s that cold, Deugo can’t even finish tapping the rest of the trees because drilling the trees could cause them to split.

This time last year, the sap started flowing around March 7, Deugo says. In 2010, it was already flowing freely by this time of year. He says there’s still time for the weather to warm up but he’s becoming worried.

“There is always some concern when you see this really cold weather and the idea that maybe it'll be a short season,” he says.

It’s a similar story in many maple syrup bushes across eastern Canada and northeastern U.S., including at Breedon’s Maple Syrup in Alliston, north of Toronto.

“Last year at this time, we were making syrup, but this year is different,” Kent Breedon tells CTV Barrie.

For Breedon and many other syrup producers, the concern now is that when the weather finally warms up, it might become too warm too fast, and the nights won’t be cold enough for the sap to thicken with starch.

That could mean a thin, watery sap that requires more boiling to get to the needed sweetness levels.

“On average years, we like to make a litre of syrup per tap,” says Breedon.”If it warms up too fast, we might make less.”

With a report from CTV Ottawa’s John Hua