Extra lemons, Invisible Ink and Secret Messages

January 5, 2018 Author: Ann Clary Gardens Are For Fun / Made with Sunshine: Growing Citrus in California / The Mighty Garden Archive

Suffering from too many lemons from your home garden? What a shame. Take one of your extra lemon fruits and turn it into a project for a young, budding scientist or undercover agent.

Harvest those lemons. Twist the base or cut the stem using hand pruners. For fruits too high to reach, use appropriate, stable ladders or climbing gear. Prevent injury by avoiding using stools, chairs, or other improvised supports for reaching upper fruits. If you cannot reach the upper fruits on a high tree, consider reducing the canopy of your tree to keep fruit closer to the ground.
Cut the lemons in half and add a few drops of water. Mix in bowl. The added water makes the ink more “invisible.”
Use a q-tip to write an invisible message on a piece of paper. Allow the juice mixture to dry.
When the secret writing is to be revealed, hold the paper up to a source of heat, such as a light bulb. The heat source will cause the lemon juice mixture to oxidize and turn brown, revealing the secret message.