pH help?

so im growing outdoors or (guerrilla growing) and i need a little advice on pH correction

the question i have for all you grow masters out there is if my ph level starts to fall say its at 6 or 5 how much lime roughly do i need to add to each of my plants as to not over correct and get it to alkoline? (they are in the Veg state and are about 4 ft high and are a mainly sativa strain)

Not sure about the ratios cause soils are different, i would start off adding a small amount of dolomite lime
and test it then re-adjust from there. If its in the 5 range your going to have to add a bit