Upcycled Hydroponic Growing Blocks Hold Moisture June 7, 2014 640 × 480 Upcycled Hydroponic Growing Blocks Hold Moisture These Upcycled growing blocks from a neighbor hydroponics farm were saved from their future in the landfill. Holding moisture is key in a drought worn farm area. Blocks also contain basalt to add as a nutrient. Other blocks are made of coconut coir