I recently saw an advertisement on TV for a glass gadget called "aqua-globe". It is shaped like a turkey baster and what you do is fill it with water through the open end and then insert that end into the soil next to your plant/flowers. The commercial claims that the aqua-globe will constantly keep your plants watered with the exact right amount of moisture around the clock. Is this a good thing? They're not too terribly expensive (I think it's $14.99 + S&H for 4 of them). They look attractive but do plants need constantly moist soil?