Yikes - first my apologies as I just now found this question and I usually answer within 48 hours. I suggest you do a soil test to see how acidic your soil is.  Then the amount of lime to add depends on what type or form of lime you are using. Calcium carbonate is more gritty and dissolves more slowly than hydrated or powdered lime which dissolve quicker so you would use less. It is important to read the instructions on the bag of lime and figure out the amount based on what the pH of the soil is currently and how much you need to raise the pH to get it to be around 6.5 which is good for growing flowers. You must mix the lime into the soil by stirring it and it does take time to work so applying the lime in the fall is a good idea as the winter rains will wash it down to the root zone before spring planting. One more tip - the first year after applying lime you may not see the results you want but the second year things will grow better - again this is because lime works slowly over time. Good luck and Keep Growing, Marianne Binetti