The killing frost that hit the Weyburn area last week has damaged between one-quarter to one-third of crops in the area, says extension agrologist Elaine Moats.

Three days of -10 C temperatures brought development of green crops to an abrupt halt and ended the precarious waiting game farmers have been playing with their late-seeded crops.

"With a really green crop, a killing frost causes the plant cells to weaken and the nutrient transport system in the plant doesn't work. Further development isn't going to happen," Moats said.

If the crop is left to stand it will eventually dry out on its own and evaporate. Producers can speed that up by cutting the crop so it will dry faster. The frost will not affect the quality of mature crops.

"In some cases producers had already decided they weren't going to take a chance and harvested the (late-seeded) crop for green feed. In other cases the crop was pretty close to being swathable - some of that grain will be salvageable but the grade will be down. In other cases there will be no development at all.

"There's quite a range from nothing for damage on mature crops to a light bran frost on some cereals to no seed at all on the really late stuff," Moats said.

Harvest progress is about half finished in the Weyburn area, compared with 81 per cent completion province-wide.

There was limited progress last week because of the previous week's moisture and snow on the weekend. Farmers are also waiting for the crop to be dry enough to combine. Many farmers who were combining last week had access to aeration bins or had grain dry enough to store. Frost has brought an end to hopes of harvesting slough hay.

Moats says crop grades are all over the map.

"In late summer we were seeing everything from grain that was downgraded because of midge and fusarium to No. 1 high protein. We've been pleasantly surprised at the level of peas and chickpeas which were off early in pretty good grades. Certainly some lentils will be downgraded," she said.

Generally speaking canola yields have been very good, with fields in the southeast producing above normal amounts.

"We're certainly seeing mixed harvest results this year, and a lot of that is based on conditions that went back to seeding conditions last spring. That whole scenario followed through to harvest," Moats concluded.

The start-and-stop rate of harvest has given farmers an opportunity to get a lot of fall field work done, including bailing.

Cattle are now being brought home from summer pastures in preparation to sell calves.