Coarse Black Lava Rock 1/4"-3/8" by The Bonsai Supply - 24lb

Build healthier root systems and improve long-term soil performance with Coarse Black Lava Rock by The Bonsai Supply. Screened specifically for bonsai use, this premium volcanic substrate provides exceptional drainage, increased aeration, and lasting structural stability for trees in development and refinement.

With a particle size of 1/4"–3/8", this coarse grade is ideal for larger bonsai, pond baskets, grow boxes, and custom soil blends that require increased airflow and rapid drainage. Unlike organic materials that break down over time, lava rock maintains its structure for years, helping preserve the integrity and performance of your soil mix between repotting cycles.

The generous 24 lb bag is perfect for mixing large batches of bonsai soil, repotting multiple trees, or keeping your workshop stocked for the busy repotting season.

Features

• Premium volcanic substrate screened specifically for bonsai use
• Excellent drainage and aeration properties
• Helps prevent soil compaction over time
• Provides long-lasting structure in bonsai soil mixes
• Encourages vigorous root growth and development
• Reusable after proper cleaning and screening

Ideal For

• Custom bonsai soil blends
• Junipers and conifers
• Pond baskets and grow containers
• Development material
• Larger bonsai trees
• Improving drainage in moisture-retentive mixes

Specifications

• Brand: The Bonsai Supply
• Product Type: Black lava rock
• Particle Size: 1/4"–3/8"
• Grade: Coarse
• Weight: 24 lb
• Use: Soil component and drainage enhancement
• Suitable For: Bonsai soil blends and development projects

Strong bonsai begin with strong roots, and quality lava rock provides the drainage, oxygen exchange, and durability needed to support healthy trees for years to come.