This is a great idea! It uses mostly stuff that you chuck out in the recycling bin.
Basically the goal is to increase the watering efficiency by slowly watering underground where the roots of the plants are.
- Use a fine needle to puncture around the base of a PET bottle in four locations.
- Bury the bottle in the proximity of your plants.
- When it is time for watering open up the cap and fill up the bottle with water.
- Additionally a reservoir can be made from a juice container and a small length of poly hose as show.