Making soil more acidic
I bought some blueberry plants and the instructions say to add lots of peat moss to increase the acidity. I prefer not to use peat moss due to the environmental effect. Is there another way to increse the acidity? What I have available is horse manure mixed with straw (varying from 2 to 7 months aged), several old dead pine trees and old rotting hay. I've read that pine needles increase acidity, but I'm not sure if the dead needles do the same? Help?