# Growing in crushed terra cotta



## keithrs (Aug 15, 2012)

Anyone here grow Catt.'s and such in crushed terra cotta? There roots seam to like growing around terra cotta pots. The reason I ask is that I have about 200 terra cotta tiles left over from a job I did. Speaking of which I have some travertine left over too! 

Would any of it be ok to use?


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## Leo Schordje (Aug 15, 2012)

Especially some of our members in more tropical countries, where fir bark is not available, they frequently use broken or crushed terra cotta or crushed bricks as at least part of their potting mix. No reason why it would not work. Remember, each potting mix will have its own water holding properties, you will have to work out how often you water with the crushed terra cotta. Once you get the watering right, it should be fine. 

Travertine, I am not familiar with it. Depending on whether it is inert, or slightly soluble (like some limestone) will determine how / if you can use it.


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## Ray (Aug 16, 2012)

The only potential issue I can think of is that you're starting with flat tiles. Unless you really pulverize them well, the flat surfaces can help the particles stack too tightly.

Like Leo, I don't know the dissolution rate of travertine, but I imagine it's in the same realm as limestone, so could possibly be good as an additive or top dressing.


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## Cheyenne (Aug 16, 2012)

Someone from my orchid society frequently brings in cattleyas potted in broken pieces of clay pots with amazing roots. Sometimes its hard to see the pieces because there are so many roots.


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## goldenrose (Aug 16, 2012)

there are some bonsai enthusiasts that grow strictly in crushed terra cotta, it's available commercially, we use to buy 50# bags......
wonder if there's any sitting around in the garage?!


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## keithrs (Aug 16, 2012)

That's good to hear.... I have been using crushed rock and hydroton... I works good but recently I had potted some Catts in bigger pots. The crushed rock holds alot of moisture toward the bottom of the pot and it's heavy as hell. My hope is that by using crushed TC I will have better air movement around the roots. 

Travertine is a form of limestone. I was thinking it will be good to add into my paph mix and other rock dwelling sp.


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## goldenrose (Aug 16, 2012)

the commercial crushed terra cotta is small almost granular sized pieces, so I'm doubtful about the potential for air circulation but certainly could be wrong. Any broken terra cotta pots that I have, I just whack the bigger pieces, leave them chunky & have been using them for my vandas, which do very well.
Here's some info http://greenscapeaeration.biz/terragreen/mediaapplications.html


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## Clark (Aug 16, 2012)

Too bad they wouldn't work on top of sidewalk/patio/slab, in front of greenhouse.


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## keithrs (Aug 16, 2012)

Clark said:


> Too bad they wouldn't work on top of sidewalk/patio/slab, in front of greenhouse.



They could... But I'm not a fan of the look. Im more of a natural stone guy. May be I can use some as a cool floor in greenhouse that I keep planing to build.


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## keithrs (Aug 16, 2012)

Leo Schordje said:


> Travertine, I am not familiar with it. Depending on whether it is inert, or slightly soluble (like some limestone) will determine how / if you can use it.



Its my understanding that plants can't take up natural form of Ca intel fungi breaks it down into useable form?


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## Ray (Aug 17, 2012)

Fungi do not break down limestone to a significant degree. I'd consider its decomposition more "geodegradation" than biodegradation. Acid solutions (as in rainwater that absorbs carbon dioxide and sulfur compounds from the air, or fertilizer solutions) will slowly decompose the stuff and release the soluble ions for plant uptake.

As to the terra cotta, let's not forget that LECA is more-or-less the same as crushed terra cotta pots in rounded pellet form, so we know it works.


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## keithrs (Aug 17, 2012)

Ray said:


> Fungi do not break down limestone to a significant degree. I'd consider its decomposition more "geodegradation" than biodegradation. Acid solutions (as in rainwater that absorbs carbon dioxide and sulfur compounds from the air, or fertilizer solutions) will slowly decompose the stuff and release the soluble ions for plant uptake.




I had read in an organic gardening book that it was important to add mycorrhiza when you added lime to break it down into usable food for the plants. Maybe that's for the fact that "geode-gradation" is slow to happen in soil with out the help of mycorrhiza. Whole different animal! Or is it?


> As to the terra cotta, let's not forget that LECA is more-or-less the same as crushed terra cotta pots in rounded pellet form, so we know it works.



Ya... I was thinking that leca company's need to make 1" leca. It would probably cost an arm and two legs to ship.


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## keithrs (Aug 17, 2012)

I was also thinking.... How come TC isn't more popular if it is a good potting media? Aside from leca....


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## Rick (Aug 17, 2012)

If your humidity is fine you could probably grow Catts hanging from a wire with no media whatsoever. Lots of Vandas seem to grow fine this way. I've been finding roots from some of my mounted Phalaes and Oncidia types clinging to the PVC pipe and aluminum frame/shelf members in my GH. I see lots of well grown Catts in TC pots with a couple inches of organic media with the rest filled up with styrofoam peanuts. The roots grow in the styro as good as in the bark and on the clay pot itself.

The surface water in So Cal is full of dissolved Ca. So unless you are a strict RO user, there will be plenty of soluble Ca getting to your plants without worrying about how much comes from the mounting surface.


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## Rick (Aug 17, 2012)

keithrs said:


> I was also thinking.... How come TC isn't more popular if it is a good potting media? Aside from leca....



It weighs a lot compared to styrofoam peanuts. Also if you ever decide to repot its really hard to get the old pieces out. But at that point I'd probably never really repot, and just keep moving it up into larger piles of TC (until the weight crushes my benches):evil:


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## Rick (Aug 17, 2012)

keithrs said:


> I had read in an organic gardening book that it was important to add mycorrhiza when you added lime to break it down into usable food for the plants. Maybe that's for the fact that "geode-gradation" is slow to happen in soil with out the help of mycorrhiza. Whole different animal! Or is it?



mycorrhiza are probably important for breaking down old plant cell wall material to release the calcium locked up in that (which if you remember the tables on leaf litter composition is generally the greatest source of Ca in rainforest soils).

But rather than a source of Ca (or any other nutrient) limestone rock has a very stable pH over many years, while organic media tend to go acidic in a relatively short time.


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## keithrs (Aug 18, 2012)

Rick said:


> It weighs a lot compared to styrofoam peanuts. Also if you ever decide to repot its really hard to get the old pieces out. But at that point I'd probably never really repot, and just keep moving it up into larger piles of TC (until the weight crushes my benches):evil:



It's half the weight of crushed rock...


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## keithrs (Aug 18, 2012)

Rick said:


> If your humidity is fine you could probably grow Catts hanging from a wire with no media whatsoever. Lots of Vandas seem to grow fine this way. I've been finding roots from some of my mounted Phalaes and Oncidia types clinging to the PVC pipe and aluminum frame/shelf members in my GH. I see lots of well grown Catts in TC pots with a couple inches of organic media with the rest filled up with styrofoam peanuts. The roots grow in the styro as good as in the bark and on the clay pot itself.
> 
> The surface water in So Cal is full of dissolved Ca. So unless you are a strict RO user, there will be plenty of soluble Ca getting to your plants without worrying about how much comes from the mounting surface.



Your right... Some growers will just let the plant grow in the air once the plant reaches size to where it has reserves to take it to the next watering.


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## keithrs (Aug 18, 2012)

Rick said:


> mycorrhiza are probably important for breaking down old plant cell wall material to release the calcium locked up in that (which if you remember the tables on leaf litter composition is generally the greatest source of Ca in rainforest soils).
> 
> But rather than a source of Ca (or any other nutrient) limestone rock has a very stable pH over many years, while organic media tend to go acidic in a relatively short time.



Pot grower use mycorrhiza for lot of reasons, but one reason that come to mind is the coco guys that use it to help break the bonds between K, Ca, P and the coco mix. As you may know, they use lots of all three.


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## Ozpaph (Aug 18, 2012)

I assume the terracotta tiles aren't chemically treated?
Many are treated as TC stains and grows algae.
I dont know if the sealant is plant toxic, so try a few first.


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## Cheyenne (Aug 18, 2012)

Ozpaph said:


> I assume the terracotta tiles aren't chemically treated?
> Many are treated as TC stains and grows algae.
> I dont know if the sealant is plant toxic, so try a few first.



That was my only concern. Tarracotta pots are made for plants. But the tiles could contain other ingredients or chemicals. You never know what they put in things.


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## keithrs (Aug 18, 2012)

Ozpaph said:


> I assume the terracotta tiles aren't chemically treated?
> Many are treated as TC stains and grows algae.
> I dont know if the sealant is plant toxic, so try a few first.



As far as I know its just red clay and water that has been baked.... I have no problem with the algae. After all, It releases N for the plant!


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## Rick (Aug 18, 2012)

If a sealer has been used, it's most likely just sodium silicate. Once wicked up into the pores and excess washed off its pretty inert (but then your clay won't wick any water either).


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## Ray (Aug 19, 2012)

Sometimes terra cotta tiles are "salt glazed" (like shiny clay sewer pipe). Good old salt - sodium chloride - is introduced into the kiln, and the salt fluxes the surface, forming a relatively weak glass.


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## cnycharles (Aug 19, 2012)

when I bought clay tiles at lowes I asked it there was anything other than clay, and they told me 'no'. I use them for baking pizza and bread in the oven. I was also thinking about setting some in water and mounting plants towards the top, let the water wick up (or maybe make a 'box' of then glued together and put green water retaining stuff inside. maybe use it to make my own sort of 'zeer pot'

one thing to remember is that clay pots can get coated with fertilizer and waste crud, in addition to calcium if used where there is hard water; if this is inside another pot, salts might collect though maybe since they are inside a pot instead of being the outside of a wicking clay pot, salts might not build up


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