Good idea, I was rotating by bed and I don't have a very large garden. Rotating by row would likely make a more efficient use of space. I have been using litmus paper to test the soil but I am still lost as to what amends to add. The litmus test (as you probably know) only tells the pH. I don't know how to translate pH level into how much N (nitrogen), P (phosphorus) or K (potassium) to add.