Hydrofarm GROW!T GMC40l Clay Pebbles 40L Brown – Hydroponics, Aquaponics & Drainage Media

Overview

GROW!T GMC40l clay pebbles are crafted from 100% natural clay. They are clean, pH stable, and designed to deliver dependable aeration and drainage across hydroponic systems. Their unique structure creates a large surface area around the root zone, supporting the development of beneficial microbial activity and a stable environment for roots to explore nutrients from their surroundings.

What you may notice in practice

• Extremely stable in both pH and EC, helping you maintain steady nutrient conditions without frequent adjustments.
• Pre-washed to aid stability and reduce handling dust during setup.
• Drain freely and do not hold excess water, providing consistent oxygen levels near the roots.
• Made from 100% natural clay and sized 4 mm to 16 mm for versatile uses across systems.
• Will not float once fully wet, helping media stay in place during cycles.

Practical uses across growing styles

• Aeration and drainage: mix into coco coir or soil to improve air gaps and root comfort.
• Hydroponics and hydroculture: ideal for flood and drain, deep water culture, and drip systems.
• Aquaponics: suitable for root media in combined fish-plant systems.
• Decoration and evaporation control: top dressing adds a natural look while reducing evaporation.

In daily use, you receive a 40 liter bag of brown pebbles that stay stable under typical growing conditions. The pebbles are not only functional but also visually appealing when used as a top layer or decorative bed cover. The 4–16 mm sizing offers versatility for different root zones, while the natural clay composition provides a consistent medium across environments.