New Grower Adding lime to my soil mid grow?

[Scrappy]

Read the sticky on fox forest soils being low and this holds true to happy frog aswell. Oh tested at a low 5.3 plant seems to be fine but I'd like to correct it before I see issues with old growth. It says to add 1-2 cups per gallon of soil I've already added a cup to the mix before I planted how much should I add to 4 gallons at this point any tips on raising it would help.

worries about burn etc no nutes added so far.