Soybean, corn and wheat prices rose as some South American farming regions get either too much or not enough rain.
Soybeans finished up 2.4 percent Thursday; corn increased 2 percent and wheat gained 1.4 percent.
Brazil and Argentina are huge producers of corn and soybeans. There are hopes that farmers in those growing regions will produce bountiful harvests after a drought damaged U.S. crops this year and left global supplies tight.
But rain has been lacking in the central-west region of Brazil where soybeans are grown. And there's been too much rain in the wheat and corn regions of Argentina.
Although it's still early in the season, investors have shifted their focus from concerns about demand in the slower global economy to questions about supplies, said Mike Zuzolo, president of Global Commodity Analytics and Consulting LLC.
December wheat rose 12.25 cents to finish at $8.685 per bushel, December corn gained 15.25 cents to $7.6075 per bushel and November soybeans increased 36.25 cents to $14.455 per bushel.
Other commodities were mostly lower on a mixed batch of economic news. The U.S. Labor Department said weekly applications for unemployment benefits jumped last week to the highest level in four months.
Meanwhile, China said its economy grew 7.4 percent in the July-through September period from the year-ago quarter. That was slower than the second quarter's growth rate of 7.6 percent but came within the range that economists were forecasting. Retail sales also improved, which helped allay some concerns about China's economic slump. The world's second-largest economy is a huge importer of raw materials.
Gold and silver investors didn't respond favorably to the news from China, opting instead to sell appreciated holdings for a profit, said Erica Rannestad, a commodities analyst at CPM Group. Investors often buy gold as a hedge against inflation.
Gold for December delivery fell $8.30 to finish at $1,744.70 per ounce. December silver fell 36.4 cents to $32.868 per ounce.
In other metals contracts, December copper fell 0.5 cent to $3.743 per pound; December palladium decreased $6.20 to $647.20 and January platinum dropped $26.80 to $1,643.70 per ounce.
Benchmark oil fell 2 cents to end at $92.10 per barrel. Heating oil decreased 0.28 cent to $3.1866 per gallon and wholesale gasoline dropped 3.66 cents to $2.7451 per gallon. Natural gas rose 11.7 cents, or 3.4 percent, to $3.587 per 1,000 cubic feet.