I'm not an expert but this is how I understand it,,,,,,,,,
If anyone knows better please share!
I got the recipie from a tomato growing forum
(they share thier secrets more without argueing)
my understanding is that the ph of the Sphagnum moss is 4.5 so it lowers the soil ph but adds to water retention and drainage
Lime raises the ph but does so slowly, kinda like time released
Dolomite lime has mag/co in it and is used by some to fix a mag/co defficiency
EVERYTHING we add lowers ph, mollasses, nutes, etc. over the grow period without the dolomite we take a chance on the soil ph going to low because of what we have added
So as we add the nutes and stuff the water is also activating a bit more lime to buffer or compensate and keep ph levels right
Plus it is reccommended in every gardening book I have ever read
Edit, I also add 1 inch of perlite in the bottom of the pot before adding soil