Suggested: Cover the Morel mushrooms with black plastic mulch, which offers five excellent benefits: 1. Moisture retention. 2. Temperature control. 3. Frost control. 4. Weed suppression. 5. Increased yield. When purchasing the film, opt for a black porous mulch about 30 cm wider than the bed surface, which allows for good light and air permeability, benefiting mushroom growth and fruiting.