Corn inched higher after a weekly decline in U.S crop conditions reported by the U.S. Agriculture Department (USDA).
Soybeans traded both sides of even before easing on harvest pressure.
The Chicago Board of Trade (CBOT) most-active wheat contract added 13-3/4 cents to $7.00-3/4 a bushel, its biggest daily gain since 18 August.
Corn firmed 7 cents to $5.20-1/4 a bushel while soybeans eased 2-1/4 cents to $12.82-1/2 a bushel.
EU's Biggest Grain Grower
France cut its estimate of soft wheat production in the European Union's biggest grain grower by more than 600,000 tonnes on Tuesday to 36.06 million tonnes, citing wet summer weather.
Canada's drought conditions damaged the wheat harvest even more than it appeared weeks ago, according to a Statistics Canada report estimating spring wheat output at 15.3 million tonnes, down 41% year over year.
This comes at a time of strong global wheat demand, including a significant number of international tenders in the past week.
U.S. winter wheat was 12% planted as of 5 September, up from 5% last week, the USDA said.
"With $7 wheat, I think you’re going to have more wheat acres than we’ve had the last 5-6 years," said Ed Duggan, senior risk management specialist at Top Third Ag Marketing.
Meanwhile, the USDA rated 58% of the U.S. corn crop in good-to-excellent condition in its weekly crop conditions report, down 1 percentage point from the previous week, while soybean ratings were unchanged at 57% good-to-excellent. Analysts surveyed by Reuters on average had expected no change for either crop.
Soybean futures were underpinned by recent exports, though closures on the U.S. Gulf Coast due to Hurricane Ida have muted recent shipping activity.
"Seasonally, exports tend to skyrocket. We just have to get past some logistical hiccups down in the Gulf," said Terry Reilly, senior agriculture futures analyst at Futures International. "I expect that to quickly rebound and beans to go out the door, as soon as we get harvest under way."