I'm so in love with Design Sponge, they have a great collection of DIY, you can see there so much ideas! I could put this markers for my garden, but I already know what tomatoes, peppers or aubergines are... but is a great idea to do it with little children at school! So many kids don't know how plants are, they are so used to see the vegetables just in the supermarket!!
You can see all the process here! Have a warm&sunny weekend!