Water Plants While On Vacation

I had never found a system to water the plants when going on vacation that would water the plants only when they need to be watered like a good gardener would. But then I found this system that corrects this flaw:

You need a big plastic bottle with its cap and another smaller plastic bottle that can fit inside the big one, leaving a space of 2 or 3 inches. Cut the bottom of the big bottle and the top of the small bottle to keep only its straight part. Fill the small bottle with water up to the edge and you set it on the soil next to the foot of the plant. Put the big bottle on top of the smaller one with its cap on tight. You push it into the soil on a few inches so that the volume between the two bottles is a closed space.

When the temperature rises, the water in the small bottle evaporates and flows down along the inside of the big one and goes down into the soil. When the temperature is low, the water does not evaporate and stays in the small bottle, the plant is watered according to the temperature. Keeping only the straight part of the small bottle is important, otherwise the water evaporates but goes back into the small bottle. You can put more than one set for a big plant and you can use it for plants outdoors or indoors. Hope this helps! Here's what it looks like: