Building a Child's Worm Farm

Today I made a worm farm for my daughter. The idea was from a book with kid's crafts. It is a jar with a layer of sand, a layer of potting soil, another layer of sand and another of soil and then the worms and compost with aged leaves on top. Am hoping to teach her about what worms do and to allow myself the opportunity to observe them a little bit closer. I just it in a dark place and kept the lid off so that it can stay aerated. The sand I used was from the beach that I flushed several times with fresh water. Below is a time lapse of the worm farm taken over a period of one month.