Why the Grodan Pargro Jumbo Block Is Wide Rather Than Tall
Footprint is the point here. At 6 x 6 x 4 in the Jumbo gives a root plate half again the area of a four inch cube. It stays shallow enough that a flood table still reaches the top. A case holds 64 blocks and weighs about 23.75 lbs, which is light enough that one person can carry two down a row. The pre-drilled hole takes a rooted starter plug, and the foil wrap seals four sides so only the top face is open to air. Shallow blocks come back to field capacity fast after a shot. That responsiveness is the whole argument for this shape on an ebb and flow bench. What it will not do is hold a dry upper layer. Growers steering hard generative in late veg should look at the taller Biggie instead.
Running a Quick Drain Stone Wool Block on an Ebb and Flow Bench
A quick drain stone wool block behaves differently on a table than it does under drip. Flood and drain fills from the bottom, so a shallow cube saturates evenly and empties evenly. The EC in the block then tracks the tank closely enough that a tank reading means something. Basalt wool is inert and pathogen-free out of the wrapper, so nothing needs sterilising before a turn. Roots run out of the base and into the table or the slab underneath without being torn. Growers moving over from coco usually find the feedback faster than expected, because there is no buffer sitting between the feed and the root. The wrap does mean you cannot see the root mass from the side, and a squeeze test is the only real check.
Key Features
- Wide, shallow profile: More root plate area per block without the dry upper layer of a taller cube.
- Case of 64: A full bench quantity at roughly 23.75 lbs, light enough to carry two at a time.
- Pre-drilled hole: Seats a rooted starter plug straight into the block with no cutting.
- Even saturation: Flood and drain reaches the top face, so the whole cube works rather than half of it.
- Foil wrapped sides: Four sealed faces keep light out and hold evaporation to the top surface.
- Inert and pathogen free: Nothing to sterilise and nothing added to the feed before the roots reach it.
Technical Specifications
| Specification | Value |
|---|---|
| Brand | Grodan |
| Product Line | Pargro Quick Drain |
| Part Number | 328451 / 328451-S |
| Format | Jumbo block with hole |
| Dimensions | 6 x 6 x 4 in |
| Hole | Pre-drilled for a starter plug |
| Material | Basalt stone wool, inert |
| Wrap | Black and white foil, sides sealed |
| Case Count | 64 blocks |
| Case Weight | About 23.75 lbs |
| Drainage | Balanced drain with moderate water holding capacity |
| Suitable Systems | Flood and drain tables, drip lines, transplant onto slabs |
| Nutrient Contribution | None, the substrate is inert |
