Two tips learned from experience: try not to use MG soil....You will probably have ph problems with this. You said it is the only thing you can find, isn't there a really cheap mix you can get ahold of (I am reading you shop at Homedepot...look til you find something else with NO nutes...or ask someone you know that has some laying around)? Then add pearlite....next tip, get some way to measure your ph of your soil and water. If you HAVE to use MG, look up Gardenknowm's thread about it, he had to use 8.0 water to compensate the 5.0 soil. Oh and don't plant seeds in the same pot. One foot of plant per gallon. This could save you from a lot of frustrating problems....From one newb to another...lol. S