PRAGUE—Czech police have raided dozens of stores suspected of selling materials that help people illegally grow marijuana.

The Czech Republic doesn't allow the recreational use of marijuana.

In a statement Tuesday, police said they are targeting some 50 so-called growshops across the country. Among other things, police have seized fertilizer, lamps and materials that promote growing marijuana.

The police say they suspect the owners are breaking drug laws by providing people with all the necessary equipment to grow indoor pot with a high level of THC—marijuana's psychoactive chemical—and to smoke it.

The crackdown came in for some criticism.

Michal Jakes, who delivers goods to some of the stores, said on Czech public radio that sellers shouldn't be held responsible for how customers use their products.