What is hydro weed?

it is something to do with the way it is grown or processed i think. Hydro is water so i believe it is a type of resin that is made using the process of frozen water

"Hydro" weed refers to weed grown hydroponically, which means using water as a nutrient medium rather than soil. The term is often associated with higher-quality marijuana, though the truth of that connotation is debatable.