The ALM GS105 Black Waterproof Label Marker Pen is is a permanent marker and suitable for writing on many surfaces , including plant labels, seed trays, pots and signs.
Tip: Keep that empty seed packet in a safe place for easy referral and identify the seedlings in the trays or pots with plant labels instead. Using the empty seed packet on the tray only causes problems later, when you discover it has faded and broken apart with the daily watering. The saved packet will be clear and legible, if you keep it in a drawer inside!