"It's an auction and until people turn up and shake your hands, you don't know," Mrs Edwards said.
The couple farm 450ha at Moa Flat and will sell about 4000 store lambs at an on-farm auction in the middle of January, the sixth such sale they have held.
Mr Edwards said they had had strong and weak sales over the years, and learnt that many factors determined the market, and not to assume that a shortage of lambs this year would equate to high prices.
"There is potentially going to be more buyers out there because people have not had the lamb drop they are used to," he said.
But countering that could be feed conditions in January, the availability of cash and the price of prime lambs.
Mr Edwards said he would be interested in the market for ewe lambs, given the high death rate of capital ewes and replacement ewe lambs during September's storm.