Coconut coir or coco peat.
It is made from crushed up coconut husks.
I only ever grow in soil though, it is not that hard to work out when to and when not to water.
Its free. Whats this expensive man made- every time i wanna grow I gotta go to the store stuff u guys are using?? 😂
Shit. My nutes are synthetic. Dont mind me then...carry on....😇