disturbing mineral growth on clay pots
 

ever since i moved to the new house i've been having this problem. there's consistent mineral buildup on the pots that is bothering me. at the old house, the water definitely also contained higher levels than normal of Ca/Mg but it only resulted in a thin white mineral layer over the body of the pot. this time, the minerals are literally crystallizing on the edges of the pot. the new house has a water softening system but i've been using water from the hose outside, so i am really at a loss...

(the first image is what i'm used to - a harmless-ish mineral film, nothing weird)

oh also please ignore the leca balls sitting on top of the moss... it's kind of weird but I was out of bark and I wanted to cover the moss to inhibit algae growth. :)

your water is liquid rocks. it might be worth investing in a RO system, I think there is small units in the hundred dollar range. cattleya orchids can be pretty salt tolerant so depending on your collection you might be able to get away with it as long as you can stand the unsightly build up.

Pretty high level of minerals there. Do you have water testing results from your water company? Have you checked TDS yourself? You don't say how long you have been at your loccation, but how are your plants doing? I'd think you might be seeing some burnt (dark) root tips.

Could it be the pots themselves? I have similar build ups on some clay pots and the plants in them are only being watered with RO or rain water so I assumed it was coming from the clay. The plants in the pots have been doing fine for going on a year now. I’ve started pre-soaking my clay pots under the thought that I can leach some of this stuff out before throwing in the plant.

now I'm looking at it more closely. it could be a mold or biofilm, you can probably scrub it off with a sponge and some soap.

it's definitely mineral growth because i've tried rubbing it off with my fingers and it feels grainy (and dissolves in water). i've tried scrubbing it off but it always comes back... gah :P

in some parts it really does look like algal growth, but i am 99% sure it's minerals. ahk. liquid rocks. :D

fishmom - the TDS is definitely high - root tip burning occurs occasionally but not devastatingly.

aliceinwl - i'll try soaking the clay pots to leach out any minerals from now on. seems like a good thing to try because some of the larger clay pots which i bought earlier (not the same batch) are only developing the familiar white film (or nothing at all) while only the small ones are being weird. might be a manufacturing quirk. :)

Just a random thought from someone with hard well water: Do you flush your plants periodically? Even if you can catch rainwater, you could flush the root buildup. My roots never burned but, my leaf tips got brown. Then I got a mag deficiency. Now I catch rainwater water or filter my unsoftened water manually.

It is almost certainly precipitated dissolved minerals. If it was from the pot alone, it would only occur to a limited extent.

Anything that can dissolve in the water will seep through the pot wall and precipitate when that water evaporates - dissolved solids in the original supply, fertilizers, stuff dissolved from the media, etc.

If the pot wall deposits are that extensive, I can pretty much guarantee your plants will do much better if you switch to RO.

Read this stuff, then I’ll be happy to answer any questions and help you get what you need, with no expectation that you’ll buy from me, either.

Definitely quite a build-up of minerals for sure there!

Aside from any noticeable root-tip issues ----- any signs of leaf tip browning?

I also have rock water. Back in the day I grew a lot of African violets in clay pots. The mineral buildup on them was incredible, and fast buildup. Just like that crusty part you see on top, and it would get much worse.

Also watered orchids that way for a decade or so. Some didn't mind, but couldn't grow some (paph, phrag, etc) to save my soul. Once I switched to RO water, not an issue. Collect rain water or get an RO system, and don't look back. ALL the orchids will grow much better, not just the ones that are very sensitive to "rock water."