CHRONICALLY dry spring weather has dashed grain growers' hopes across northern Victoria.

In parts of the Mallee and the Wimmera, crops are too thin to be cut for hay.

Department of Primary Industries agronomist Rob Sonogan said the deterioration of crops over the last two weeks had been "unbelievable".

"We cut nearly 30,000ha last year for hay and this year, for about 28,000ha of it, there's not enough dry matter to cut for hay," Mr Sonogan said.

He said some crops had died and would not respond to good rain.

"Rain would just be a pain for some of these crops, and might cause weeds to germinate," Mr Sonogan said.

Victorian Farmers Federation Grains Group president Geoff Nalder said there was still reasonable prospects of a good harvest on the Mallee's lighter soils.

"What we don't need is temperatures of 38C and howling northwesterlies," Mr Nalder said. "Rain after next weekend will just bring weeds."

However, rain in the next fortnight could add hundreds of thousands of dollars to crops in southern Victoria.

AWB Ltd grain marketer Brad Knight said there was still potential in the Western District and Wimmera for a good harvest if the areas received spring rain.

However, he doubted Victoria would have enough cereal grains to meet livestock demand and would need to get grain from NSW and South Australia.

Jeffcott farmer Damon Coats has had to cut 640ha of his 800ha of cereal and canola crops due to dry weather.

Last year, Mr Coats also had to cut 80 per cent of his crops for hay, while the previous year it was 60 per cent.

"I am getting used to being a hay farmer rather than a grain farmer," he said.

Birchip agronomist Bruce Adriaans said about a quarter of crops within 30km of Birchip were "cactus", while 20-25 per cent had been cut for hay.

Of the remaining crop about half would be very low yielding and the rest below average.

"It is bad, it is really getting too late for us now," Mr Adriaans said.

Lameroo stock agent Pat Larsson said his district had only received 175mm of rain and some paddocks would not be harvested.

"On the lighter ground we might be reaping a little," Mr Larsson said.

Darryl McCrae, from Agritech Rural Horsham, said yield concerns were moving south, with frosts and hot windy weather during the past week.

"There has been considerable amount of lost yield over the past three to four weeks and the weekend has taken a lot of hope we had away," Mr McCrae said.

Rod Schulz from Peppers Plains, in the northern Wimmera, won't be cutting his crops.

Mr Schulz cited a letter written by his grandfather in the late 1940s that told of the farm having brown crops on Jeparit show day (which falls this week).

Then it rained.

"The crops went from brown to a 10-bag average. A rain is never too late," Mr Schulz said.