Grodan Pargro Jumbo, 6 x 6 x 4, w/Hole, Case of 64Grodan Pargro Jumbo, 6 x 6 x 4, w Hole, Case of 64Pargro is an ideal stone wool growing media, for consistent results without the need for sophisticated irrigation schedules. Pargro is lightweight stone wool made from basalt rock. Its a highly uniform substrate thats pathogen, disease and seed free. The material is inert so it will not add or hold back any nutrients giving you complete control over your plants. The Pargro family of products are made