Grodan ParGro Slab 36 x 6 x 3 in | 3 Pre-Cut Holes, Bag of 12

Why the Grodan ParGro Slab Ships Ready to Plant

Each slab is 36 x 6 x 3 in, or 91.4 x 15.2 x 7.6 cm, and the bag holds twelve of them. This one is item 328465, with three openings cut at 10 x 10 cm. That opening is about 4 x 4 in, which is the footprint of a four-inch block. A rooted 4 in cube drops straight in with its base on the wool and no knife work at all. Three openings per slab also fix the spacing for you, spread evenly along the length. The wool itself carries the advanced wetting agent that keeps water content and EC even along the slab. Being inert, it binds no nutrients and needs no flush before the first feed. The foil is printed and light-excluding, which is what keeps algae off the exposed wool at each opening. A bag of twelve covers thirty-six plant positions. That is one bench row in most single-room layouts.

What Pre-Cut Holes Change on a Planting Day

Cutting openings by hand is the step where a transplant run loses its afternoon. It is also where inconsistency creeps in, because a hole cut slightly wide leaves an air gap and roots hesitate at the join. Factory openings remove both problems in one go. The trade-off is that the spacing is now fixed, so the layout has to suit three positions per slab. Everything else about the routine is unchanged. Flood the bag until the seams go taut and leave it a full half hour before anything goes in. Cut the drain slit at the lowest point beneath the seam, keeping the blade clear of the wool. Seat each block so the base touches the slab and press gently instead of pushing. Run one or two drip stakes per opening and stop short of the base, because a stake pushed through sends the feed to the floor. Check content at both ends of the slab for the first few days, since the far end is where an uneven line shows up first.

Key Features

• Three openings per slab: Cut at 10 x 10 cm, which takes a four-inch rooted block straight from the tray.
• Twelve slabs a bag: Thirty-six plant positions, enough for a bench row in a single-room layout.
• 36 x 6 x 3 in format: A 91.4 cm slab that runs the length of a standard bench without trimming.
• Advanced wetting agent: Keeps water content and EC even from one end of the slab to the other.
• Inert wool: Holds no nutrient charge of its own, so no flush is needed before the first feed.
• Printed light-excluding foil: Shields the wool around each opening, where algae would otherwise start.

Technical Specifications