Oyster Shell Calcium

[orchidlady]

calcium carbonate from oyster shells and just pure carbonate calcium ( I have seen on bottles of calcium) are the same or different. I am a little confused. I have always assumed that if the calcium is from oyster shells the lable says so. But now I am not sure. if the bottle says carbonate does that mean its from oyster shells.

Oyster shell is just one possible source of calcium carbonate. For example, egg shells are also composed of calcium carbonate. Calcium carbonate can also be made chemically. Therefore, if it says it is specifically from oyster shells then it should be. If not, there may be another source.

Susan

[Halloamey]

The bio availability differs between each source of calcium carbonate (CC) like lime stone, oyster shell, egg shell etc. Even though they are primarily CC, they also have other components. Like in egg shell the CC is bound together my a protein matrix in oyster shells it is bound by chitin and some more complex proteins and polysaccharides making it less soluble and less bio available.

[tawv]

Hey all, looking for info on calcium for different orchids I found this thread. I have calcium grains that are used for 'fertilizing' gardens. Can I safely use that for the orchids too?

I read '1 teaspoon of calcium, 3-4x a year' for Dendrobium phalaenopsis. Any types of orchids that do NOT like to be calcium-o-fied?

[Apple Mary]

Thanks For the advise

[nen]

Hi I came across this thread as I need to repot all my paphs and as I live near the sea I wanted to use crushed oyster shell in my substrate. Can anyone tell me if there is a "best way" to add the shell to the mix? Sprinkled on top? mixed evenly throughout the substrate?. I was thinking of doing both, but since I have not repotted yet, I thought I would ask here. My paphs are all in a mostly bark mix & grow well but are long overdue for some fresh medium. Thanks in advance

[Apple Mary]

I've never heard of using crushed shells in a planting medium. How interesting. It make sense though. Hope it works out well. Actually, I didn't know they need extra calcium. Let us know how it fares.

[miss*behave cutie]

The bio availability differs between each source of calcium carbonate (CC) like lime stone, oyster shell, egg shell etc. Even though they are primarily CC, they also have other components. Like in egg shell the CC is bound together my a protein matrix in oyster shells it is bound by chitin and some more complex proteins and polysaccharides making it less soluble and less bio available.

i agree , calcium carbonate cannot be absorbed by the orchid roots so it needs to be bonded with metal for it to be delivered to the orchid for absorption. i looked at most calcium supplements they sell in orchid supply stores online and they say it's 96% calcium carbonate.
i will definitely be looking out for the chelated version they use in hydriponics.
xo Leah

[raybark]

i agree , calcium carbonate cannot be absorbed by the orchid roots so it needs to be bonded with metal for it to be delivered to the orchid for absorption. i looked at most calcium supplements they sell in orchid supply stores online and they say it's 96% calcium carbonate.
i will definitely be looking out for the chelated version they use in hydriponics.
xo Leah

I don't know where that info came from, but it is apparently a gross misinterpretation of the facts.

None of the mineral ions are absorbed in the form of their source materials; they all must be in solution. And calcium is a metal; and alkaline earth metal, but metal nonetheless.

Calcium carbonate certainly can be absorbed by orchid roots. The issue is its solubility is very low, so there is little in solution for the plants to absorb. If the 4% of your example "96% calcium carbonate" product is an acidic material, it is likely that the Ca⁺⁺ will be soluble.

Most fertilizers contain calcium in the form of calcium nitrate, which is a simple, soluble ionic compound, and not a chelated compound. If you're searching for chelated materials, you're going to waste your money.

[miss*behave cutie]

thank you ray for your clarification , i will look over my source of information and maybe check if i misunderstood the calcium bioavailability to orchids.