Best TDS level for schomburgkia/myrmecophila

[Tom and Sam]

Hello orchid board members!

I just got a reverse osmosis unit and wanted to know how much fertiliser (in ppm) I should aim for schomburgkia splendida and myrmecophila tibicinis.

I am currently just using orchid focus bloom/grow and seaweed fertiliser, mixed together for the general feed around 120 - 200ppm as my main collections are slippers.

Is it wrong for me to think myrmecophila tibicinis would like to have high dose of fertiliser? as I read somwhere that they usually have an ant colony living in it and would get ant droppings.

Any suggestion is greatly appreciated.

[Ray]

Welcome aboard, Tom or Sam.

How much fertilizer to use depends a lot on how often you intend to feed. Think of feeding as being analogous to controlling the calories in your diet - if you eat three meals a day, they each should be about a third of that contained in a single meal per day.

Personally, I recommend no more than 75-100 ppm N per week. 6 divided by the %N on the fertilizer label tells you the teaspoons/gallon for 75 ppm N; 8/%N is for 100. (6.9/%N and 9.2/%N = ml/L for 75 and 100 ppm N, respectively)

Those ppm values are for nitrogen only, and the only way to tell what the TDS will be for those concentrations is to mix them up and measure them.

I hope you are aware that now that you're using pure water, you'll have to make sure you provide enough calcium and magnesium, so either your fertilizer will need to contain them or you'll need a supplement.

Ladtly, I believe you are incorrect that the myrmecophila would need more nutrition. If I'm not mistaken, the ants help provide sufficient nitrogen in a relatively nutrient-lacking environment, rather than adding to an existing, adequate supply.

[Tom and Sam]

Thank you very much for your reply Ray.
I will fertilise the targeted nitrogen level you recommend.

I am aware of cal/mag need to be added for the ro water and I purchased some nutrients for it.

Would you recommend put something like schomburgkia/myrmecophila in semi hydro at all? I know a lot of people grow them mounted or almost bare root in a basket as they like to dry out between watering. Some people pot them in a clay pots because it is porous and this would help with the drying process but I really dislike using clay pots as they accumulate a lot of salts and have to break a lot of roots when repotting.

Anyone has success with semi hydro within this spieces?

[Roberta]

Ray will have to speak to the possibility of semi-hydro for these, but I have trouble visualizing the pure logistics - they get large, and those husky pseudobulbs are heavy. I have one in a basket with minimal medium (just a bit of large bark) but it has somewhat escaped, and another mounted, both quite happy - and big... the only orchid in my collection that out-competes it for size is Dendrobium speciosum. (I don't grow Grammatophyllum but that would be in the same class of potential beasts...)

[Ray]

Any plant CAN be grown in semi-hydroponics, but that does not mean that anyone can do so with any plant, because there is a lot more to orchid culture than just how the water and nutrition is delivered, and that's all S/H really addresses.

I also agree with Roberta - big plants in big S/H pots weigh a ton, so even if all the other boxes are checked, consider that before proceeding.