Pargro Slab 36" x 6" x 3" with 3-4" x 4" pre-cut holes, case of 12

Pre-Cut Stone Wool Slab for Drip Hydroponic Systems, 36x6x3in, 3x4x4in Holes

Pargro Slabs give drip-to-waste and recirculating hydroponic systems a pre-cut stone wool slab sized to receive a rooted starter block, with consistent density and drainage from one slab to the next in a run. That consistency is what lets a drip system irrigate every slab the same way instead of adjusting per unit.

This 36in x 6in x 3in slab has three 4in x 4in pre-cut holes, packaged in a case of 12.

Key Features & Benefits

• Pre-cut planting holes — sized for immediate placement of a rooted starter block without on-site cutting.
• Consistent slab density — drainage and moisture retention behave the same way across every slab in a run.
• Chemically inert stone wool — won't shift the pH or nutrient balance of the solution running through it.
• Multiple slab dimensions — sized for different drip channel widths and hole configurations depending on the system.

Who Should Use Pargro Slabs

Growers running drip-to-waste or recirculating drip systems who want a value-tier stone wool slab, at a more accessible price point than Grodan's premium slab line, are the best fit for Pargro.

About Pargro

Pargro is Grodan's value-tier stone wool product line, manufactured using the same ROCKWOOL Group stonewool process as Grodan's premium slabs and blocks but positioned at a more accessible price point.

Frequently Asked Questions

How do I set up a Pargro slab in a drip system?

Position the slab in your growing channel with the pre-cut hole facing up, pre-wet it with pH-adjusted water, then insert the rooted starter block into the hole and connect drip irrigation to it. Roots grow down and out from the block into the slab as the plant establishes.

Why does slab density need to be consistent across a run?

Inconsistent density between slabs means some hold more water and drain slower than their neighbors, which shows up as uneven growth across a drip system. Pargro's consistent density is meant to keep drainage and moisture retention behaving the same way slab to slab.

Is stone wool chemically inert?

Yes, stone wool doesn't alter the pH or nutrient balance of the feed solution passing through it, so growers control the root zone through their nutrient program rather than through the media itself. That makes the slab a neutral, inert base rather than an active ingredient in the feeding program.

Can a Pargro slab be reused for a second cycle?

Most commercial drip operations use a slab for a single cycle due to pathogen management concerns in shared irrigation systems. After harvest, spent stone wool can be broken up as a drainage amendment or disposed of per local waste guidelines.

What hole configurations are available across the Pargro slab line?

Configurations vary by size, including slabs with three smaller pre-cut holes for multi-plant spacing and a single pre-cut hole sized for one starter block per slab. Choosing the right configuration depends on your plant spacing and drip channel layout.