The U.S. mushroom industry is on pace for huge growth this year, but it also faces production challenges.

Volumes are projected to be up 20% over the past five years, or 30 million pounds per year, according to a news release from the Washington, D.C.-based American Mushroom Institute.

Mushroom sales in July were the most for any July ever, and on par with levels normally seen during the holidays, according to statistics from the San Jose-based Mushroom Council.

This fall, supplies have struggled to meet demand, with some growing areas experiencing production challenges and labor shortages.

“It all starts with creating the composted growing medium for the mushrooms, and growers had difficulty finding adequate raw materials, and (there are) other setbacks which have led to lower crop yields,” Laura Phelps, the institute’s president, said in the release. “Also, since mushrooms are grown in highly automated, climate-controlled buildings, quickly adding extra capacity isn’t possible or as easy as plowing up a few more acres. As a result, product shortages may occur at least through the end of the calendar year.”