Oyster Shell for Orchids

[Fairorchids]

Originally Posted by SADE2020

I wasn't laughing at absurd...by the contrary, I am a trur beliver in Milk & Orchid, but some others disbelieve or found it gross for apartment growing.

As you said 3rd world countries growers use what they have more accessible. My sister recommends to her clients. I heard that many times in my trip to South Asia and Ecuador, not only for Cal but antifungal as well, but not for all orchids or it has to be balanced with Mag and there is when I get lost.. I prefer one thing for all!

---------- Post added at 06:10 PM ---------- Previous post was at 05:57 PM ----------



@Kim.. I don't know about shells but here is a grower in Colombia, huge nursury in the Hills of Medellin (alma del bosque) that grows 40% in limestone and 60% in 5mm bark. The Phap tour in his video is woow.

@ Sade:

That choice (40% limestone/60% 5 mm bark) is fine, based on their water quality, watering schedule and fertilizer schedule. In reality, they could probably grow in 40% granite nuggets and 60% 5mm bark, and get the same results.

You can't take one factor in isolation. You have to consider the whole picture.

[WaterWitchin]

Wise words Kim. I always pay attention to your thoughts.

[SADE2020]

I totally agreed that what matters are the nature basics. It was just an example of a nursery that care for limestone... ;-) ..and yes, where they are they can probably grow whatever except succulents

[tmoney]

hey there, thought of this thread when doing some research for a new species we have on order (thanks to ray for prodding us to the paph dark side). anyway, copied below is an excerpt from travaldos care tips for paph gratrixanium:

Paphiopedilum gratrixianum are grow only in the pot. A mixture of bark of coniferous trees with peat is best suited as a substrate. In addition, it is strongly recommended to add lime to the substrate. Practically not exhausted source of lime are seashells, which can be thoroughly washed from salt, crushed and poured into the substrate.

thought it was interesting....

[Leafmite]

I have no evidence whether it is scientifically sound or not but I cannot dismiss the use of oyster shell outright. It seemed to work for my orchid society all those years ago. I haven't had issues with black rot as I did when I had issues with Calcium deficiency since I started using egg shell and oyster shell. Many substances made with Calcium can be effected by acidic environments. It was widely in the news that Carbon dioxide absorption by oceans having an effect on shell fish. The pyramids and Spinx in Egypt are rumored to be affected by pollution. Some of us have acid rain. Many people use pine bark/sphagnum moss (both often create an environment less than 7pH. Even if a little Calcium is released very slowly, maybe that is all the plants need to prevent Calcium deficiency issues?
Again, I have not read studies on specifically testing oyster shell in a lab with rain water or RO water bark and sphagnum so I still think that people should make their own decisions and have their own opinions on this. Personally, I will continue to use egg shells and oyster shells as it seems to work for me (or I have been very lucky all these years since that long ago disaster). Maybe Oyster shell is nothing but a good luck charm but...I will take it.

[Onomaya]

So I called the nursery in question today (for other reasons initially) and also asked about the oyster shells.

They use it as a slow release source of Calcium, not against algae as I originally thought (they use pebbles for that on plants that are in spaghnum).

The reason behind it is apparently that acid residue in air/water can still interact with the shells and dissolve them into Ca-sources the plants can consume.

Hope this helps.

[estación seca]

Egg shells have a large amount of protein along with the calcium. Adding them to potting medium provides nitrogen.