Thanks for the nice comment.

To answer your question: 1) Yes, they do. But by measuring the moisture in the soil, you will get an alarm when a certain amount of water is extracted from the soil, being caused by heat, sun or a thirsty plant. After quite a bit of experimentation, we found a threshold value that works for most plants. Not cactuses ;) 2) Indeed we check more often than needed. But if the plant is getting dry, we want to briefly signal every five minutes and before we do that, we do a quick soil check.