I have been using Fabric Paint on the clear plastic knives I have stuck in the ground around my garden beds. I have a numbering system for all my seedlings that corresponds back to their stats in my Plant Step database and photos of the blooms and scapes that I took of each plant recently. I also use a #2 pencil to mark the mini blind labels that I planted under each of my newest seedlings. I'm trying to be fool-proof, but alas, somehow I wound up with numbered knives that I can't find the corresponding plant. Never fails .... best laid plans don't always work 100%. It's a curse!