Hey fill out a grow problem form and people can help you. if your using a 400watter and can't finish with more then 10grams I would say its not the soil more factors are a muck. I do fine with just about any soil. What strain are you using? bagseed and crappy lights and ave soil produce more then what you have yielding, try to regroup and go over your setup and work things up a bit. outdoors can be fun, indoors can be tricky as I am finding but still 10g sux for a 400watter. any pics of what your doing?