There are several ways that you can tell if a plant needs water, touching the soil to see if it’s dry or looking to see if the leaves are drooping are just a couple. Or you can look at your Plant Monitor and see if it’s flashing!
It’s an electronic sensor that can tell if the soil requires moisture and I built one from a kit from Maplin yesterday. The kit included a circuit board and components which needed to be soldered together.
I’ve soldered kits before like the Crab Bot which I would link to here but I can’t find the post where I first mentioned it! D’oh!
Soldering can appear scary but it really isn’t. Doug taught me how to solder but if you have a HackSpace near you, you may be able to learn there.
And here’s the Plant Sensor in situ.