[0005] There are a large number of

[0005] There are a large number of patents for the device to water a plant, when the caretaker is on vacation. U.S. Pat. No. 6,134,833 to Bachman and Mehta (2000) is for the self-watering plant container. Based on this patent, Natural Spring Controlled Watering Planter became commercially available. The planter is made of two shells, snapped together to form the sidewall of the pot. Between the inner and outer shells is an airtight water reservoir with a plug on the top for water filling. At the bottom of the planter, there are holes, which allow water to seep from the water reservoir to the soil medium. The control mechanism is by a hydrophilic polyethylene sensor for soil moisture. The sensor is placed inside a plastic tube and buried near the root ball of the plant. The tube is connected to the top of water reservoir. When the soil is dry, the dry sensor lets air pass through the tube and into the water reservoir. This increases the water pressure in the reservoir, which forces water through the water holes to the planter. The water starts to wet the soil from bottom to top. The wet sensor stops the air passage to the water reservoir. The air pressure in the water reservoir gradually drops below one atmosphere, which stops the release of water from the reservoir.