Growers Edge® Block Covers 4 in (40/Pack)

Grower's Edge Block Covers block light from reaching the growing media. This helps to reduce algae and pest problems in Rockwool and other growing media. Easily set up the covers by placing the white side up and using a small object, like a toothpick, to hold the cover in place. Each package of Grower's Edge Block Covers contains 40 covers.