When he had set the torches on fire, he let them go into the standing grain of the Philistines and burned up both the stacked grain and the standing grain, and also the vineyards and olive trees. Bible

“the stacked grain and the standing grain.” This was the time of the wheat harvest (Judg. 15:1), so the grain was partially harvested. Some grain was already in stacks waiting to be threshed, and there was still standing grain in the fields that had not been cut yet.

Commentary for: Judges 15:5