Prices are higher for soybeans, corn and wheat as some South American farming regions are getting either too much or not enough rain.
Corn and soybeans rose at least 2 percent Thursday. Wheat also finished higher.
There are hopes that farmers in Brazil and Argentina will produce large harvests to help ease short global supplies of corn and soybeans.
Although it's early in the season, some investors question whether the adverse weather could take a toll on the South American crops.
Other commodities are mostly lower on a mix of economic news. U.S. jobless claims last week were at the highest level in four months. And China's economy is showing signs of improvement.
Prices are lower for gold, silver, copper and oil. Natural gas and cocoa are higher.