Garden lyme

I think what the local farmers do is get an existing soil Ph test done (seem to remember it was around 4.5 Ph round where I lived, which is very acid) then apply the appropriate amount of lime to bring it to the ideal Ph for the crop you are growing (normally around 6.5 Ph methinks?) If you google it I am sure you will find a formulae for how much to apply per Acre/Hectare/Square yard/metre.
I know it's a lot, but you have to decide which areas you need to treat and which can get away without it?