Corn bids were steady to weak at processors, with the basis under the most pressure in areas west of the Mississippi River.
Processor bids for soybeans were steady to firm, rising by 3 cents per bushel in Decatur, Indiana.
Bids for both commodities were mostly flat at river terminals around the region.
Corn bids were steady to weak at ethanol plants, easing by 2 cents per bushel in Council Bluffs, Iowa.
Country movement was slow on Monday morning despite strength in the futures market that pulled cash prices to levels growers had previously targeted for sales, grain dealers said.
But most growers were reluctant to book deals before they finish more of their seeding tasks, a dealer in northern Ohio said.
Wet weather around the region has left most farmers well behind their typical planting schedule, raising concerns about the size of harvest.