I'm planting blueberries for the first time. I know they like an acidic soil. In much of my gardening, I double dig the raised beds in th spring adding a good amount of aged manure and compost. So what can you add or what do you do to ensure an acidic soil for blueberries. I do not have a soil tester. Can someone explain acidic versus.....whatever the opposite is? Not real sure about additives to the garden beyond fertilizer and composting. Thank you.