For my next project, I want to set up an irrigation system for some large-ish planters that my other half has ordered. Each planter is about 1.5m long, 45cm wide and 35cm deep. I've seen lots of tiny little sensors about 6cm long that look like they're aimed at pots but `I don't think this will be any good for these planters as the top will dry out quicker than the bottom and it's likely to over water them.
Does anyone have any recommendations for sensors that could be used in this sort of container?
I guess the alternative would be to bury them deep in the soil but I'm not sure that would be a good idea unless the electronics is protected.