How to raise and lower ph with vinager and baking soda?

Someone told me I could raise and lower ph with vinager and baking soda? How do I do this without causing harm or shock to my plants. They are in week two of veg. and reading like 7.3 ph, need to drop just one point, if that, how do i do this easily and how much do i use of which product?

lemon juice, i think 10 drops per gallon will lower it a point

is this a 1-day fix like the vinager or will it keep soil neutralized longer?