FlytrapCare Carnivorous Plant Forums

So I had purchased a Home Depot 6 inch Terra Cotta pot for my Cephalotus. I potted the plant up and thought life was good. However, I started reading a reddit thread about someone who broke their TerraCotta pot to find that the interior was a strange grey color, almost like cement. People hypothesized several different possibilities: the pot might be of a different clay body coated with real Terracotta, the pot wasn't kiln cooked long enough, or this was "black coring" a natural phenomenon when cooking pottery. Curious to see how my terracotta pot would compare, I smashed a spare pot I had purchased, and low and behold, the same greyish interior.

Home Depot (Pennington) 6 inch pot, grey cement-like interior

I was very surprised, since the pot says "made in Italy" (brand is Pennington). I didn't know what to make of this, and became very unsure if these Home Depot pots were safe for Cephalotus.

Anyways, people had posted that TerraCotta pots from Michaels did not look like this. So I went out and purchased a a few 6 inch clay pots from Michael's (brand is Clay Pot By Ashland). I smashed one of these Michaels pots and the interior was red terra cotta through out, as I had originally expected. I also noticed it was a little bit harder to break the Michaels pot than the Home Depot one.


Michaels pot, pure terra cotta red throughout

But maybe this is just aesthetics, and maybe doesn't really matter. So I decided to settle this conclusively by running an experiment. I added some crushed shards of each pot to pure rain water and measured the impact to the PPM of dissolved solutes. The results were very dramatic.

Baseline measurement taken immediately after immersion:
9ppm for Michaels

9ppm Home Depot


After 7 hours:
19-21 ppm for Michaels

120-122 ppm for Home Depot

Michaels bottom, Home Depot top

I'm so glad I caught this early enough and will be repotting my Cephalotus in a Michaels pot. I'll take a few more measurements for longer intervals (especially to make sure the Michaels one sustains it's superiority) and will post them here. Hope this helps folks out there interested in using TerraCotta. I think the lesson is, if you're not sure, smash a spare pot of the same brand/batch, make sure it's pure red terracotta throughout.

Btw: big thanks to Steve_D, I had read this very insightful posts in this old Clay Pots thread clay-pots-t4880.html

I hope my post gives further insights. I'm imagining the Home Depot is the "clay bodies" type Steve mentioned.

Interesting results, thanks for posting the numbers. That said, I've read at numerous sites that any terra-cotta pot is risky.