Grodan Improved Gro-Block Mini-Blocks | 1.5in - Strips - Not Shrink Wrapped - 1.5in x 1.5in x 1.5in (Case of 2250 blocks)

Small-Format Stonewool Strip for Seed Propagation, 1.5in Bulk Case

Seed propagation at high density calls for a stonewool format smaller than a standard Gro-Block, one sized for individual seeds or tiny cuttings rather than an established rooted plug. Grodan Improved Gro-Block Mini-Blocks measure 1.5in x 1.5in x 1.5in, built on the same hydrophilic fiber technology as the rest of the GR-series but scaled down for early propagation.

This strip ships without shrink wrap in a bulk case of 2,250 blocks, sized for commercial propagation runs that go through mini-blocks quickly.

Key Features & Benefits

• 1.5in x 1.5in x 1.5in Size — one of Grodan's smallest formats, sized for seeds and tiny cuttings rather than rooted plugs.
• Hydrophilic Fiber Structure — manages water distribution at a small scale for even germination.
• Strip Format — individual mini-blocks stay connected in strips for handling on a propagation tray.
• Chemically Inert Media — doesn't affect feed solution pH or nutrient balance during early propagation.

Who Should Use Mini-Blocks

Growers starting seed at high density, or propagating very small cuttings that don't need a full-size Gro-Block yet, are the fit for the 1.5in Mini-Block strip.

About Grodan

Grodan has produced engineered stonewool growing media since pioneering the process in 1969, and as part of ROCKWOOL Group extends that same fiber technology down to small-format products like the Mini-Block strip.

Frequently Asked Questions

What are Mini-Blocks used for?

Mini-Blocks are Grodan's smallest stonewool format, at 1.5in x 1.5in x 1.5in, sized for starting seeds or very small cuttings rather than accepting an already-rooted plug. They're typically the first stonewool medium a seed or cutting touches.

How do I use Mini-Blocks for seed starting?

Pre-soak the strip with pH-adjusted water, then sow one seed per mini-block into a small indentation on its surface. Keep the tray consistently moist through germination.

When should I transplant out of a Mini-Block?

Move seedlings up to a larger Gro-Block, such as a GR4 or GR6.5, once roots have filled the mini-block and the plant needs more root volume to keep developing. Waiting too long can restrict root growth in the small format.

What's the difference between the shrink-wrapped and unwrapped Mini-Block strips?

Both are the identical 1.5in mini-block strip. The difference is only in outer packaging, with one shrink-wrapped for storage and the other supplied loose in bulk case quantities.