use powdered hydrated lime to raise the ph make it more alkaline
use powdered sulfer to lower the ph, more acidity to it
can usually get both at local garden center for a few bucks a small bag

using peat type mix has given me problems in the recent past and have recently changed to a humus/pearlite mixture(far superior imho). using a peat mixture you will most likely want to make the soil more alkaline
texas grass Reviewed by texas grass on . how to adjust soil ph i was just wondering if there is anything that can be done to a pre-mixed soil that is too hot for most plants to lower the "hotness" of it and how to go about lowering the ph of it also ive heard that putting your dirt in the oven for a little bit kills any bugs/bacteria that might hurt your plants. ture ? or a waste of time ? Rating: 5