Try peat moss or pCked around the sides or even some bark it will not rot as fast as the bark and wii look a lot better
Love your dipping tins @MaryW3121. They look fantastic.
Let me also extend to you, @Paradise, @OsmayG and @Dawn12 a very warm welcome to the Workshop community. It's fantastic to have you join us and we look forward to reading more about your projects and plans very soon. Please feel free to post anytime you need a hand or have something to share.
@Dawn12 - I don't believe you could buy anything like these old Grape tins from Bunnings, but I'm sure members like @kaylah_rose might like to give you some suggestions, such as vintage and antique stores. Where are you based?