| 摘要 |
<p>A pair of lever arms are hinged together at one end and disposed beneath a plant container, compression spring being disposed between the other ends of said lever arms and a flexible water supply hose being sandwiched between said lever arms intermediate their ends. Thus, when the soil in the container is dry and thus light, the spring opens the arms and allows water to flow through the hose to the soil; when the soil is moist, and thus heavy, its weight overcomes the force of the spring and compresses the hose to cut off the supply of water.</p> |
