FYI, I use a moisture meter on my house plants, and found it doesn't work worth a shit in well aerated, loose, MJ friendly soil. It would say dry even right after watering. I just go by the pot lifting technique. I think you'll really be able to tell when they are light. They weigh like half as much as after watering.
It was a SUPER CHEAP one (maybe $5), but seems to work fine for my houseplants. They are in various pottery, so the lift test is tricky.
There's always the super low-tech method of shoving a finger down there and feeling for moisture. I do that occasionally when I'm not quite sure.