Grodan Pargro QD Biggie Block with Hole, 6" x 6" x 6" - Case of 64Pargro Quick Drain Stonewool Grodan Pargro line has been modified to be the driest value priced Rockwool on the market. Pargro is the leader among affordable horticultural Rockwool. There are other brands that offer the same low price, but you end up sacrificing quality. Not with Pargro! Since it is made right in the Grodan factory, you can be assured of a high quality product at a great price. Pargro Quick Drain (QD) blocks are up to 14% drier than