# Calcium question



## cdub (Jul 21, 2006)

OK so I've been doing a lot of reading on various forums regarding integrating oyster shell into potting mix or using it as a top dressing for those species who benefit from it. I don't have any osyter shell, but I was at the beach today and picked up some various shells in the sand and water. Does anyone know if I could I crush them and use them in the same manor? (after rinsing the salt off of course!)? Is oyster shell superior? Thanks!


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## kentuckiense (Jul 21, 2006)

cdub said:


> OK so I've been doing a lot of reading on various forums regarding integrating oyster shell into potting mix or using it as a top dressing for those species who benefit from it. I don't have any osyter shell, but I was at the beach today and picked up some various shells in the sand and water. Does anyone know if I could I crush them and use them in the same manor? (after rinsing the salt off of course!)? Is oyster shell superior? Thanks!



I got oyster/clam shells from a trail in Colonial Williamsburg. I washed and sterilized them.


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## cdub (Jul 21, 2006)

Yeah well mine are the VA Beach variety!!!  But I guess they all originate from the same location at some point. I wasn't sure if people are using osyter shell because other shells are bad or something. The calcium deposit in the shells should be basically the same though right? I dunno.


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## kentuckiense (Jul 21, 2006)

cdub said:


> The calcium deposit in the shells should be basically the same though right?


That's what I figured, but I very well could be wrong.


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## Heather (Jul 21, 2006)

I don't see why you couldn't use other shells. I used a shell to up the pH in my fishtank. Wow. Shells. Cool.


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## cdub (Jul 21, 2006)

OK then Zachary, how do I sterilize them? Weak bleach solution? Microwave? Autoclave?


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## SlipperFan (Jul 21, 2006)

What about cleaned/sterilized/crushed eggshells? I remember when I was a kid growing up on a farm that we used to feed them to our chickens for adding calcium to their diets.


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## cdub (Jul 21, 2006)

Excellent point about the eggs. I was blinded by all this oyster talk that I failed to think of other calcium sources. How 'bout Tums? Sprinkle some of that over paphs!!


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## PHRAG (Jul 21, 2006)

Water them with milk once a week.


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## cdub (Jul 21, 2006)

Kidding about the milk PHRAG? Again, seems like another good idea. Would the milk calcium be in the same usable form to the plants as it is when leeched from the shell material?

My plants would probably benefit more from me not thinking so much about providing them with a extra pinch of calcium.


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## Heather (Jul 21, 2006)

cdub said:


> My plants would probably benefit more from me not thinking so much...



Perhaps!
:rollhappy:


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## gary (Jul 21, 2006)

PHRAG said:


> Water them with milk once a week.


wouldn't cream give me fatter buds?

gary


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## rad (Jul 21, 2006)

heavy cream might make them a little self consious, i'd try the light cream


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## Heather (Jul 21, 2006)

Yeah, but the carbs are lower in cream...


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## ScottMcC (Jul 22, 2006)

go to a drug store and buy some Os-Cal. It's made from oyster shells. no script needed!


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## Eric Muehlbauer (Jul 22, 2006)

Tums are just flavored chalk.....I'd go for plain blackboard chalk...but actually, then you have the risk of plants getting too much Ca at once...I'd go for the shells, myself. it doesn't matter...clam, oyster, its all the same. Any pet store will sell crushed oyster shell for cheap....may be a buck or 2 for a small container (used for birds..) It will last you a very long time...you only need a teaspoon or less. I would use it if you are growing in bark...If you are using a more neutral mix, like chc, along with a Ca containing fertilizer like MSU, I really don't think its necessary (unless its a higher P type, like Dyna-Gro, which is more acidic, and its not bufferred by Pro-tekt...)...take care, Eric


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## Rick (Jul 22, 2006)

Overall I'm not sure how much the issue of using oyster shell, lime or other calcium forms has to do with the plants requirement for calcium as opposed to the plants requirement for having its roots in a basic environment.

I am an oyster shell advocate, but many people do just as good with the same species as myself without it. I have seen many cases though when calcareous species have been in collections, growing well for many years, but not blooming, go into bloom after repotting with a mix with oyster shell.

As an aquatic toxicologist I know that the role of pH and calcium concentration has a profound role on the effects and bioavailability of almost all the major and minor nutrients important to orchids, and the toxicity of other salt species that can build up in the soil. And the various orchid species (along with the fungi and bacteria they also associate with) will be adapted to particular environments around their roots, with pH and Ca concentration being two of the biggest and most influental parameters shaping this environment.

Bottom line is that the source of calcium is not so important as the cumulative effects of a certain pH and calcium concentration regime that the calcium source provides.


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