Bring your fabric pieces back with wrong sides together.
Next we will pin the bottoms together, but include two elastic strips to help the cover to hold it’s shape.
I laid the elastic onto the short width of the box base, and cut two pieces to the exact size. As some of the elastic will be encapsulated within the seam, this will give it a little resistance when on the box.
Fold the ironed bottom edges in to face one another on both pieces of fabric (to the insides of the fabrics) and pin all around.
I placed the elastic about a centimetre in from each corner for the square box, but 1 inch in from the corner for the oblong box.