It has been said that adding powdered, hydrated lime to a stack of bales will keep pests away. I’m here to tell you not to bother with adding the lime. I have two main reasons.
1. It doesn’t really work that well. There is no way that you can cover every little space with the lime and so there will always be areas for bugs and/or mice to make their homes. That’s okay. It’s part of the deal. Those critters will all be gone once the stack of bales is accessed for construction. As long as you protect the bales well by stacking and covering them properly, the minuscule impact that the mice/bugs could have is not worth bothering with.
2. It’s really dangerous. If you sprinkle dry lime all over your bales, you will be breathing dry lime throughout your entire build. This means anytime you move the bales you can expect to have dust clouds form. When notching: more dust clouds. When tamping: you guessed it…more dust clouds. This is a great way to burn your eyes and/or lungs and it makes the overall build very unpleasant.
If you stack your bales well (in a pyramid) and keep them up off the ground, you will do a better job of deterring pests. Another smart detail is to place the bottom course of bales on edge so that the strings are not accessible to mice. If they are exposed, mice can chew on the twine and ruin the entire bottom course.