Pickle manufacturers are forced to drop prices to entice people to buy pickles again. During a particularly hot summer with lots of barbecues, pickle demand soars. It's too late that season for farmers to grow more cucumbers, and pickle supply is low. Pickle companies raise prices to help supplies stretch further. As pickle price moves up, more people want to grow and sell them.
Rival companies notice that pickles are lucrative.
Soon more companies are making pickles as fast as they can. Farmers are switching from growing squash to cucumbers. In the American marketplace, the demand and supply match up fairly closely.