...you can get by with it ...if you keep the nute feedings down to 1/4 strenght.....20/20/20 for veg cycle....and I like 10/52/10 for flowering....good drainage is critical....don't overwater...get a moisture meter.....HPS lights...etc...etc...enjoy....(us old dudes need to stick together)....:thumbsup:..

Do you have a good complete growguide?...if not...get one.