Grodan Expert Delta Slab 

The Expert stonewool in these Gro-Slabs has vertical fibers that allow the water (nutrient solution) to move quickly through the slab. This quick draining process prevents water logging and enhances aeration of the plant roots. A popular choice for hydroponics growers! 

Grodan stonewool is pH neutral, making it easy to maintain the ideal pH values between 5.5 - 6.5. These pH levels are essential for optimum plant development and substrate integrity.

Expert Delta Gro-Slabs are packaged in biodegradable UV resistant poly sleeves that give you these benefits:

Prevent algae growth
Prevent diseases from moving from slab to slab
Minimize evaporation
Allow total saturation before using

Use the Grodan Expert Delta Gro-Slabs for the final stage of your planting by "blocking on" smaller stonewool (rockwool) plugs and blocks. Do this by first saturating your slab with a complete nutrient solution no lower than pH 5.5 for 24 hours before planting.

Next, cut drainage holes in the plastic wrap. Lastly, cut an "X" for each plant and fold back flaps to place your Grodan Gro-block onto. Withold watering for 2-3 days to encourage plant roots to grow quickly into the slab.

We recommend placing 4 plants onto each 36" long slab. Gro-Slabs measure 3" thick.

More info from the Manufacturer (PDF format - Lots of detail.)