GROW!T Coco Caps, 6", Pack of 10

Block Algae Growth on Rockwool Without Single-Use Plastic, 6"

Light hitting an exposed rockwool block does more than just look untidy, it feeds algae growth on the block's surface, and algae competes with roots for nutrients while inviting fungus gnats to lay eggs in the moist growing medium. GROW!T Coco Caps solve that without covering the block in single-use plastic: a reusable coconut-fiber cap slips over the top of the block, blocking light from reaching the surface while letting the block breathe.

This 6" Coco Cap is sized for larger 6" rockwool blocks, commonly used for bigger plants or extended vegetative growth before transplant.

Key Features & Benefits

• Reusable coconut-fiber construction — replaces single-use plastic block covers with a cap that can be washed and used again across multiple cycles.
• Slips over standard rockwool blocks — fits directly over the top of the block without adhesive or a separate mounting step.
• Blocks light from reaching the block surface — cuts off the light exposure that feeds algae growth on exposed rockwool.
• Breathable natural fiber — covers the surface without sealing it the way some plastic covers do.
• Sold in a pack of 10 — sized for outfitting a full tray or bench of blocks in one purchase.

Who Should Use Coco Caps

These caps fit any grower running rockwool blocks who wants to cut down on surface algae and the pests it attracts without adding another single-use plastic item to a grow room's waste stream.

About GROW!T

GROW!T is Hydrofarm's exclusive soilless-media brand, spanning coco coir in loose, chip, and block formats along with graded perlite and pH-stable clay pebbles for drip, deep water culture, and flood-and-drain systems. Coco Caps extend that lineup into a simple rockwool accessory rather than a growing medium itself.

Frequently Asked Questions

How do Coco Caps prevent algae?

Algae needs light to grow, so blocking light from reaching the moist rockwool surface removes the condition that lets it establish in the first place. The cap sits directly over the exposed top of the block, covering the area most exposed to grow lights.

Can they be reused across multiple grow cycles?

Yes, they're made from a reusable coconut-fiber material rather than single-use plastic, so they can be cleaned and used again on a new block. That cuts down on the plastic waste a disposable cover would add cycle after cycle.

Will they trap too much moisture against the block?

No, the natural fiber material is breathable rather than sealed, so it blocks light without trapping moisture against the rockwool the way an airtight plastic cover can. That breathability helps the block surface dry between waterings instead of staying constantly damp.

How is this different from a plastic block cover?

A plastic cover typically seals the block and is designed for one use before disposal, while this cap is made from a breathable, reusable coconut-fiber material. Both block light, but the coco cap adds breathability and reuse.

When should I put a cap on a rockwool block?

Add it as soon as the block is placed under grow lights, since algae growth starts as soon as light and moisture are both present on an exposed surface. Waiting until algae has already established makes cleanup harder than preventing it from the start.