Q&A for How to Make Concrete Flower Pots

The formula for the concrete mix is one part cement, two parts sand and three parts gravel or crushed stone.

If it does, you can always scrape it out at the end, but I would tape some plastic around the bottom of the tubes before inserting. When everything is finished, just cut the plastic away from the tubes at the bottom of the pot.

The "part" is a reference to the portion used to measure the material. Whatever container is used for one material, it is used for the next material. It is similar to the use of a one-cup measurement in baking. A part can be any measure, as long as other ingredients use that same proportional measure.

Concrete is porous, so sealing it can be helpful in keeping water from seeping out. If you wan to paint the concrete, it will help to seal the surface before applying any paint. Not sealing will allow paint to soak into the concrete, and it will take much longer to dry (as well as needing to use more paint).

No, as concrete could ooze out of the cardboard and surround the mold. So a metal or plastic pot is ideal.