If you have plants in your house that you want to keep hydrated while you’re on vacation, you could ask someone to enter your house every day to do it for you. Alternatively, you can use a rope or a shoelace. This is called wick watering. It involves making use of the capillary action of a piece of rope, where water can simply crawl upwards.
Look at the principle at work here:
All that’s necessary now is to place the rope near a pot with a plant. When you place the rope in the water, it will take a few hours for the rope to begin wicking out the water, so don’t expect to see water dripping immediately.
A good implementation of wick watering plants can be seen here: