Soil Ph help

My soil Ph is around 7.5 and I am watering with water Phed to 6.5. Soil is mixed with some dolomite lime, kelp meal, vermiculite, and perlite. My questions is why is the soil Ph staying at 7.5 and not dropping down to the desired ph, and what can I do to correct this?

Soil has buffering capacity -- these are ions attached to the soil that neutralize the mild acid in your water. Hence, no change in soil pH. Your soil has dolomite added; hence more buffering than usual toward the alkaline side of things. Adding powdered aluminum sulfate (available at nurseries, possibly Lowe's in season) is the cure to lower soil pH. I don't have a formula for you - sorry. You might try the FAQ's on this forum, or just do a Google on "adjusting soil pH" or the like.

Do not make your water more acid to try to affect soil pH -- it probably won't work, and it will shock your plants in the process.

If your plants look good and are growing strong, you should strongly consider doing nothing. Messing around with your soil and rootballs trying to make minor adjustments often causes more harm than just letting things be. A pH of 7.5 certainly isn't outrageous, and MJ is a very resilient plant. Also, unless you have a really titsy pH meter built for soil, I wouldn't trust a reading that isn't at least a solid 1.0 point off of where you want to be -- cheap meters, color tab systems and the like are not that tightly accurate.

Good points---You can add straight peat as a top soil and work it in, that would lower your soil PH. You could also add a small amount of sulphur. If your meter is correct you could also get chealeted micros such as LILLY MILLERS transplant with B1(would be available thru-out PH range).