What to know about the Uni-Slab


Recommended Usage

The Uni-Slab is specifically designed with one plant in mind, hence the name. This smaller size meets the challenge of mobility for re-arranging plants as needed. The slab has certain advantages over the big blocks; one, the top plastic protects completely from algae growth and two, the low height provides a sturdier base-meaning the plants are less likely to fall over. Use drip or top irrigation for Uni-Slabs with Gro-Blocks™ on top.


The stone wool volume of the Uni-Slab is 304 oz. (Hugo’s is 216 oz).

Step 1 : Cut square/round hole
  1. Cut square/round hole in the top surface to make room for the 3” or 4” block(s). Lay the cutout plastic piece on the Gro-Block’s top surface to slow algae growth.
  1. Fill the slab bag with pH 5.5 water and let it be for 30 minutes. Cut two slits at the bottom side of each side of the slab to drain out excess water.
  1. Mix up the same nutrient solution that you have been using for the plants you are about to transplant to Uni-slab.
  1. Irrigate each slab until it has received 1.4 gallon of nutrient solution. Discard the drainage water.
  1. Make fresh nutrient solution in tank and adjust back to pH 5.5.
Step 6 : Place a 3” or 4” block with plant onto the Uni-Slab
  1. Place a 3” or 4” block with plant onto the Uni-Slab. Insert a drip stake into small block.

What Would You Place On The Uni-Slab?

Well Rooted Starter

Think of the slab as a shoe, and the plant as the foot. While the Uni-Slab is too large for one tiny plant, several tiny plants will thrive on it.

  1. Well-rooted starters (Macroplugs or Mini-Blocks) can be placed into the slab by first carving top holes in the Uni-Slab. As many as eight small plants can thrive in the Uni-Slab.
  2. Place well-rooted Gro-Blocks (3” or 4”) on top of the Uni-Slab. One block per slab works best, as these are generally med-large plants. One can also place a block as large as the Hugo on top of a Uni-Slab.

Uni-Slab “No-No’s”

  • Do not use Ebb & Flood if you are placing a block on top of the Uni-Slab. Most flood systems will not fill the tray high enough so that the block also gets water.
  • Don’t remove the outside plastic covering, only cut openings in the bottom for drainage, and “X” or “O” openings in the top to accommodate the top plants. The plastic covering will protect the roots from light and minimize algae growth.