Repotting a large Angraeucum (Angraecum Crestwood 'Tomorrow Star')
 

I have a really big Angraecum plant. It started flowering in Fall, but then when we got the unprecedented torrential rains, most of the flowers blackened. But it's putting out another flower stalk.

While it is growing new leaves, one leaf has totally yellowed, but it's a bottom one. However, now a higher leaf is starting to yellow.

It seems to me that the orchid bark substrate has broken down. Basically the particles seem much smaller just beneath the surface layer.

So I want to repot. Is it okay at this point to repot into 100% high quality sphagnum moss, directly from 100% orchid bark?

Also, it's in a 1 gallon pot right now. The roots are not overgrowing or out of the pot or anything. In fact there's not even much roots at the substrate surface. So is it okay to repot into the same size pot? If not, what should the next increment be, maybe up to 1.5 gallon? I have not yet researched the potential fully grown size of this species, if anyone might happen to know.

:thanx:

Yes its totaly fine to put it back into the same size pot if the plant fits. Sounds like that might be a good idea for you but a picture would help know for sure.

Personally I would worry about a 1 gallon pot full of moss. I would put it in bark to make sure drainage is good.

If your plant is in a 1 gallon pot, I bet it is fully mature. That said, there is no maximum size for an orchid. They continue to get larger as they age, and they can potentially love forever. Generally when they get too large you can find a way to divide it into peices to make it more maneagable.

Ray has an awesome article on his website about roots and culture. Thought to sum it up, when roots are grown they adapt to their environment at that time. They cannot adapt to a different environment once mature, so repotting from bark to moss might cause a lot of rot. I’d recommend reading his article.

Remember that an Angraecum grows somewhat like a Vanda. So you need just enough moisture around the roots to keep it hydrated, but lots of air. I would use medium or large bark rather than sphagnum. Sphagnum would be fine in a basket where it could dry quickly but in a pot, you don't want it to stay too wet.

The internet suggests that Tomorrow Star is a cross of Angraecum Sesquipedale and Veitchii. I have had two Sesquipedales for a year now, from different sources, one is in a 3 inch pot and the other a 6 inch pot. The small one was in bark and the larger one I repotted into a mix of bark and spagnum and I watered when approaching dryness and they were both sort of unhappy... they grew leaves steadily but then lost lower leaves and didn't grow any roots. I repotted both into lecca in a semi hydro setup in the fall and they both started growing roots like crazy and the new leaves are much more lustrous and healthy looking.

My conditions are rather different from yours, but I've heard of other people who have had success growing them in inorganic media and either watering frequently or giving them constant access to water (semi hydro).

As was mentioned, large Angraecum tend to grow similarly to Vandas, and growing in 100% Sphagnum moss is generally not recommended, particularly if you're in Southern California. The roots need lots of air circulation on top of enough moisture.

You can repot into a similarly sized pot as the old pot if there are no new roots.

You may use a pot with lots of open slots or holes all around for air circulation, and if you're concerned about not being able to provide enough moisture with 100% bark as the potting media, you may try medium or large grade coconut husk chips. Be aware that medium or large grade coconut husk chips look very dry even after watering, but the clue as to how much water is needed is to observe the roots. If the roots remain wet for 1 full day (24 hrs) or more, you may want to consider waiting until they dry out completely before watering again.

They are native to eastern coastal Madagascar where they grow in trees. They extend quite a way into the mountains so they have a wide temperature tolerance. They are wet most of the year, with an onshore breeze. I think many people underwater them. The big Angraecums grow much better for me when they never dry out. I grow them in S/H.

Sphagnum should work well if watered properly. Don't soak it thoroughly. Merely run water over the top for a second or two. That's all. The water will diffuse through the moss, leaving it barely damp and well aerated. Water again when the top of the moss is crisp dry.

Coastal environments can be windy even if moisture is high, so there is still quite a bit of air circulation. If they need that much moisture, the roots should not stay dry for more than 1 - 2 days.

If it is decided to use 100% Sphagnum moss as a potting medium, then I recommend being mindful of how wet it stays or how much air circulation is getting to the roots. Orchids that like lots of moisture can still get root rot.

Looked up the hybrid... there is no Angcm. Tomorrow Star, I think it is Angcm. Crestwood 'Tomorrow Star'. Crestwood is, indeed, Angcm. Veitchii (sesquipedale x eburneum) x sesquipedale. In southern California, marginal for outdoor growing (eburneum 25% is quite cold-tolerant, sesquipedale 75% more of a warm grower). I suspect that it just got a little too cold when blooming. I grow sesquipedale mostly outside, but when it starts to spike (typically December-ish) I bring it inside.

You have lots of good advice here on medium/watering. The goal (with multiple ways to achieve it) is moisture but lots of air. I grow Angcm. sequipedale in a pot with large bark. I grow other Angraecums in sphag in hanging baskets. So... you choose what works for you to achieve that "moist but airy" combination.

Thank you for this. I bought the Orchid from Norman's, and it seems that the orchid bark it came in is actually small, not even medium. Should I switch to medium, or continue with small?

Is there a good website or book that talks about these kinds of factors, ideal substrate material and particle size, level or moisture vs air circulation, etc? I know of IOPSE, which talks about temp, light, and humidity... what's a good why to become versed on the rest of these important factors?

Also, would sphagnum work with an air pot, for this Orchid? Something like pictured...https://m.media-amazon.com/images/I/...AC_SL1500_.jpg