Bonsai Tree Soil Additive - 2 lbs. (1 Qt.) Lava Rock is a naturally occurring volcanic cinder that has a porous structure which makes the material lightweight and highly moisture retentive.
Incorporate into your bonsai soil mix to increase drainage (aeration).
It will absorb up to 40% of its weight in water.
Small lava rock (1/4 inch) is the best "sand" component around because it is "sharp" and has very irregular surfaces. Features:
2 lb. bag