So if you want to luxury of water only and maybe even don't having to mess with the pH of your tapwater, unless it's way out of whack...I would suggest Organic living soil.
You don't need much to get started, but you do need to buy it all at once...So if you are talking enough material to get twenty pots worth of grows out of it, we still need to know how many pots you are going to be using. I'm gonna assume you are talking about 4 x 5gallon pots = 20gallon of mix. That's doable on a tarp outside in the garden, or if your missus isn't home in the Livingroom, lol
So what you need is the following basic stuff...
- One (or two) large plastic bin(s) with a lid (total about 30gallon in size) to brew your mix in.
- A tarp large enough to mix everything on.
- 15 gallon of quality soil, don't skimp out on this one. Go for some sort of 'lightmix' for young seedlings.
- 5 gallon peat or coco...dealers choice
- 5 gallon perlite or the other thing, whatchamacallit...
Then for the living part...You can go many ways, but the easiest it to buy a ready made starter pack. ie, like
@DCLXVI suggested from the build-a-soil website ór if you live in Europe, then I would suggest you try out
BioTabs. They got a '
water only' strategy which changed my life!
Any way, which way you go...You will have to mix all that together and let it brew for a while. I suggest you do this inside in the bins so the temperature stays nice and warm which will help the bacteria and mycorrhiza to grow faster and colonize the soil. One thing I really recommend you add to the soil is worms...Not any worms, but compost worms. ie, Dendrobaena and Tiger worms. These will eat all decaying matter and while doing so aerate your soil.
You will end up with about a third to much, but keep this to start your next batch of soil if you need to replace it anytime in the future.
