GK-Organics Lava Worm Powder 5 litreImproves Consistency While Delivering an Array of Minerals GK Organics Lava Worm Powder is a combination of volcanic rock dust and worm castings. Add it to your substrate when potting up (at no more than 10% of the volume) and it will improve the consistency. It's naturally very rich in minerals (including scarce trace elements) which massively reduces the risk of encountering deficiencies.