Chances are you& have a bottle of tomato ketchup in the cupboard or fridge. Many of the bottles are now the plastic squeezy type. Rather than simply popping the empty bottle in the recycling bin next time you finish a bottle why not have a go
Here is an idea for a vertical garden in a classroom (plus a fish tank). This could also work in other places -- homes, places of worship, community centres, etc. Maybe even outdoors? With a mesh covering over the fish tank, the cats couldn't get in.