Cool Thumb-controlled Watering Pot Made With Recycled Materials, tutorial. The original earthenware “thumb pots” were used in 17th and 18th century English gardens. This clever watering device is reproduced using salvaged plastic bottles and jugs. It is ideal for watering delicate seedlings. Using - Take your thumb off the hole when you are ready to water your plants. Removing your thumb allows the water to gently stream out the holes on the bottom.