Pineapple express auto

No need to reinvent the wheel. Many home center and online sell automatic plant watering machines. They are inexpensive and work well. Mine is powered by the mains electric and also has battery backup and can be programmed to water as often as you want and for as long as you want. It clips to the top of a bucket and you drop the pickup hose into the water. Then you run the tubing and emitters to your plant. My device waters by time. So, before traveling I measured how much water I gave the plant each day. Then I tested the watering machine having it discharge into a small container and I timed how long it took to dispense the amount of water I wanted. Then I set it to run for the appropriate time.