Hydrofarm Rockwool Block Covers 4" Pack of 40 special-order Cell trays are specifically designed

Cell trays are specifically designed to help your seedlings form proper root systems and allow for proper drainage to avoid mold issues

and the controller unit does the rest

multi-purpose growing medium that contains a mycorrhizal inoculum (Glomus intraradices)

with optional add-ons for NIR+UV-A and UV-B (coming soon)

It has dual outlets

Hydrofarm Rockwool Block Covers 4" Pack of 40 special-order Cell trays are specifically designedDescription Product Details: Block light from media Reflect light to plant leaves where it's needed most Eliminate algae and mildew growth 40 dual sided block covers per pack Specifications Barcodes: 10638104945780 (GTIN) 638104945783 (UPC A) Dimensions: 5. 4L x 5. 2W x 5. 6H (CS) 5. 5L x 4. 5W x 0. 3H (EA) Shipping Weight: 0. 16 lbs.