Self watering insert

Rescale this model as needed, I made the walls a little bit thicker than needed in the default scale, so unless you scale it to be very small, it should still get at least 1-2 perimeters.

Check the preview after scaling!

If you change the scale of the model a lot, you might see some problems, like walls getting too thick.

I'm not happy with the scalability and the holes for watering, something I hope to improve in a future version of this model. On the other hand, I suspect that for most pots, it will work just fine, so it felt like a shame not to upload it.

No supports

The watering holes have a thin solid layer at the bottom, so that you don't need to use supports. The printer will bridge one layer, you can this plastic with a scalpel afterwards.

After you scale the model to your desired size, use the Cut tool in your slicer to separate the bottom from the top. This makes the model printable without supports, you just have to use a tiny bit of glue to hold the two parts together (you can check the layer preview to find out exactly at what height to cut). 

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