My wife keep complaining about the plants dying when we go on holidays. So, I created a device that slowly dispense water for the duration of our holiday.

Material

1. 3x water bottle, 1.5 litres
2. Piece of string (recommended)

Instructions

Please, browse the photos to help with the instructions.

1. Print the parts: 1x self-watering-system, 1x self-watering-system_screw
2. Screw the screw in the screw hole of the watering system.
3. Fill up to 3 bottles with water. Arrange the bottles in a triangle configuration.
4. Put the watering system upside down on the 3 bottles.
5. Screw the bottles by turning the bottles themselves, one by one, until tight.
6. Attach the bottles together with a piece of string, for better stability (optional).
7. Flip the watering system right side up. Be careful to not break the tip of the screw. Note that some water may drip out through the small air hole.
8. Open the tap to get the water to drip out, one drip at the time.
9. Put the watering system in a plant pot and attach it to a post with a piece of string.

NOTE: The water will slowly flow out of the bottles, one bottle at the time. The order depend on the level, imperfection in the print, etc. Just make sure the watering system is secured, the centre of gravity will change as it empties.

Duration

After some experimentations, I found out that the self watering system last for about 2 weeks when it drips once every 20 seconds. Just make sure the tip of the dripper doesn't touch the ground, otherwise capillary effect will suck the water out quickly.

Updates

I have print several self watering systems. I have identified issues and did some adjustments. Here is the list:

2024-08-25: The air holes were too big. They significantly increase water lost through evaporation, especially in the desert where I live. I replaced the air hole with a small hole. I used the sacrificial layer trick to put the hole in the middle of the flat surface. It turns out the sacrificial layer is quite useful. It limits water evaporation even more, prevents insects from getting in and doesn't limit air flow. The water is going out so slowly, air has no issue getting it. It also makes it less messy when moving it around.