When marijuana shops open their doors to the public in January, shoppers at the back of the line might notice something missing once they get inside: the weed.

Nearly every state that allows recreational marijuana had some shops run out or run low in the first days of sales. In Colorado, some customers were greeted with signs telling them to check back the net day. In Nevada, higher-than-expected sales in the first week left shelves near empty.

On Jan. 1, it will be Illinois’ turn.

“I’m fully anticipating there’s going to be product shortages in the early days,” said Kris Krane, president and co-founder of 4Front Ventures, which owns a growing facility in Elk Grove Village and Mission South Shore dispensary in the South Chicago neighborhood. “There just isn’t going to be that much product available on Jan. 1.”

Like elsewhere, interest and demand for weed is expected to be strong, but factors specific to Illinois also could lead to shortages. Many of the state’s 21 growing facilities are expanding capacity, but construction takes time. Furthermore, the state so far has licensed only seven of them to grow recreational weed, and it takes a cannabis crop about three months to grow. [Read more at Chicago Tribune]