Repotting a specimen Catt. gaskelliana?

[gdupont]

I have a Cattleya gaskelliana specimen, with over 20 pseudobulbs. I'm in Massachusetts, indoor humidity around 30-40%, temps around 68-75 indoors. I don't want to have to water it every day.

I repotted it a few years ago – before I knew better!! – in a large plastic pot in very tightly packed sphagnum moss. Oops. I'm paying for that mistake now!

So, I'm repotting.

I'm thinking of potting it in large orchiata bark. But since it will need a large pot, I'm thinking of using terra cotta, since I wan't to make sure it's not getting waterlogged. Does this sound like a good idea? Other suggestions?

[Louis_W]

An inert media like LECA would be good but you may need to water more than you want to in that case.

Bark will probably enable you to water a little less often, it just won't last as long.

Whichever you choose, the plant won't want to come out of that terracotta pot. You'll just need to drop it into a bigger one in a couple years

[Ray]

Changing the potting medium will likely result in short-term root loss, but if the plant is strong and actively growing, that should be only a minor setback.

In coarse bark and a clay pot, you'll need to water more than with sphagnum in plastic, but it's probably a worthwhile change.

[estación seca]

Be sure you repot only when new roots are just beginning. If you need to water a plant in sphagnum every day it's either using a lot of water or the only living roots are those outside the pot.

[gdupont]

To clarify: in the sphagnum and plastic pot, I watered it very occasionally, once or twice a month, and just a little bit. It grew fine but I think it could be healthier. Then one day I watered it too much before I went away for two weeks and a few pseudobulbs turned yellow and died.

So I want to pot it in something that's a better fit for it.

[Ray]

A more open mix with far more watering is the way to go.

As was first taught to me by someone here, and later backed up with calculations based upon carbon fixation, water is, indeed, the driving force for growth.

In order for any plant to add one pound of tissue, it only needs about 5 grams of NPK fertilizer, but 200 pounds of water to be taken up and chemically processed. If you add to that the estimated transpirational loss of plants to be well in excess of 90% of what it absorbs, that inflates the demand for water to be about a ton or more. (And we really have very little knowledge about what percentage of the water we apply is taken up, outside of "little".)

[gdupont]

Originally Posted by Ray

A more open mix with far more watering is the way to go.

As was first taught to me by someone here, and later backed up with calculations based upon carbon fixation, water is, indeed, the driving force for growth.

In order for any plant to add one pound of tissue, it only needs about 5 grams of NPK fertilizer, but 200 pounds of water to be taken up and chemically processed. If you add to that the estimated transpirational loss of plants to be well in excess of 90% of what it absorbs, that inflates the demand for water to be about a ton or more. (And we really have very little knowledge about what percentage of the water we apply is taken up, outside of "little".)

Thanks, Ray! Should I go with terra cotta or plastic in your opinion? Deep or shallow? Orchiata large ok?

[Ray]

Originally Posted by gdupont

Thanks, Ray! Should I go with terra cotta or plastic in your opinion? Deep or shallow? Orchiata large ok?

As I don't know your growing conditions or how much watering you're wanting to do, I cannot make such recommendation.

Personally, I'd go with plastic and the coarse Orchiata, if not plastic with LECA.

[gdupont]

Originally Posted by Ray

As I don't know your growing conditions or how much watering you're wanting to do, I cannot make such recommendation.

Personally, I'd go with plastic and the coarse Orchiata, if not plastic with LECA.

My apologies Ray. I thought the info I had provided would be useful – I grow indoors, humidity 30-50%, temps 68-75%, it gets good morning and afternoon light in the sun room – and I'd prefer to water ~twice per week on average. What other information would be helpful? Many thanks for the guidance.