Potash was once made from wood ashes and used to feed soil and make soap. It is read as renewal from what has been burned away, and as nourishment for new growth.
Has this come up in your dreams before? What was going on in your life then?
My Cosmic Code has a private dream journal. Write a dream down and the app picks out the symbols in it, shows what dream books say about them and, over time, which words recur across your entries. The journal is stored on your device only.