automatic watering systems
As I plan and brainstorm, I realize that this thing I have to do every day called a job means it will be hard to water plants in the heat of summer possibly when they actually need it. So I thought of automatic watering systems.
I know these exist, but are they worthwhile?
Can they be used for multiple types of plants and container sizes, that might all have different watering needs?
Are they timed, or do they use moisture sensors?
Are the sensors sensitive enough to sue in a very loose, well-drained mix like Al's 5-1-1 or gritty mix? I ask because my moisture meter ($16.99 Rapidtest) doesn't register anything even right after watering even in most peat-based soilless mixes, let alone bark-based. It only works in heavy soil in the ground. It doesn't seem sensitive enough to sense the moisture in a loose media.
Finally - can liquid fertilizers be added with them?