I'm new to the city and I'm starting my first hydro system now. I've already got my seeds, lights, ph tester, reservoir, pumps, fans, etc. but the garden center in my town does't have perlite, only vermiculite. I heard rock-wool is a good alternative, any suggestions? I'd also like to know if my seeds can go sterile if they're not planted in a while... should I put them in the fridge or freezer? What is the best method for growing in small spaces? As many opinions as possible would be appreciated.
Lava rock, verm, perlite, anything that is good at retaining water should work. I use plain lava rock in my system and it grows huge plants. You also want a medium where the roots can anchor themselves to -IMO
you said your starting a hydro grow then vermiculite & perlite is of no use to you as they are mainly use in soil to provide more aeration. what kind of hydroponics system are you going to use?? start your seeds off in rockwool cubes after a week or two or(once you see the roots coming out from the bottom) put them in 4"x 4" rockwool cubes, see pics then when you start to see roots coming out again move them to your hydro system i use one similar to this one, see pics i use half and half lava rock at the bottom then rest is topped up with expanded clay pellets (if you use just clay pellets then i found that the roots grow down to quickly) HOPE THIS HELPS