My cactus and succulent collection is growing faster than my pot collection is. I've been using paper pots lately for small cuttings, and yogurt cups with drainage holes for larger plants. These aren't very permanent solutions though, and I don't want to pay a dollar a pot for the small terra cotta pots I would need.
I was wondering if it would be ok to use concrete to make pots for indoor plants. I've read about hypertufa planters, but they always seem to be for large, outside pots. Would it be safe to make small sized pots for cacti in a similar manner to the hypertufa planters? This way I could get exactly the pot sizes I need for these plants. I'm just wondering whether a small cactus in a concrete container would be damaged by the minerals used in the cement, or if cured cement would be as safe as a fired clay pot.
Using concrete for indoor pots?
Concrete, and especially weak lightweight concretes like hypertufa, rely on thickness to hold them together, which means they work better for large pots than small ones. Also, the coarse materials prevent them even forming thin structures. You might be able to make a cement-based mix that has finer materials and can be used for small pots.
Also, remember that anything made from cement is alkaline. Very alkaline when fresh, but it will continue to leach out lime (as in caustic lime, much stronger than limestone) for years. Some plants won't like that.
Also, remember that anything made from cement is alkaline. Very alkaline when fresh, but it will continue to leach out lime (as in caustic lime, much stronger than limestone) for years. Some plants won't like that.
--ian