Watering Bulbophyllum-- do they really like it soggy?

[Spotted Milti]

Hey guys!
I have two bulbophyllums (sumatranum and macranthum). I purchased them as a replacement to my very first bulbo, which was a sumatranum as well. I read up about them for a week before I bought the first one and everyone was mentioning that they basically "can't be over watered" and love moisture and air, of course, but that watering wasn't going to hurt them too much. Well guess who killed hers with rot? This gal. So, I bought two new ones as replacement and water them every 3-5 days instead of every day.

I know everyone's environment is totally different and so everyone's watering habits are definitely different, but is there any particular reason mine went downhill so fast? The sumatranum was in good shape, but the roots weren't nearly as shallow as I expected them to be. As a first-time grower to this type, I wasn't sure what to expect but hopefully things will get better with these two new guys.

Now I'm a little concerned they might be underwatered... The sumatranum (the new one) is in an opaque pot with an unknown mix and the macranthum (a giant one btw) is in some sort of bark mix (not sure why) full of algae. Any advice on keeping these guys alive and avoiding rot (my biggest killer). They're also both starting to grow out of the pot, so I guess I also have a question about when is the best time to repot them.

My growing conditions are:
In my bedroom, which gets a southern exposure (shaded in the afternoon). I have a grow light for cloudy days. Humidity is 50-70%, temps are 64-70 right now in the winter, and they get watered probably every 3-5 days (trying to stay cautious since I can't see into the pot).

[Ray]

Yes, they can be soaked, but the roots still need lots of air.

The problem with some potting media is that when soaked, all of the voids between the particles remain full of water, which cuts off air flow and suffocates the roots. They key is finding one that stays wet without that happening.

Those temperatures are a bit low for bulbos, and that can set them up for root issues, as well. You might consider purchasing a seedling heat mat to put under them. It will provide plenty of warmth for little investment or operating expense.

[Spotted Milti]

Thanks, Ray!
The heat mat is a good idea, I'll definitely look into it. Until then, I'll do my best to keep the watering under control.

[King_of_orchid_growing:)]

Bulbophyllum can go without water for quite a long time before they give up entirely.

The myth that they cannot drown from being overwatered is just that - a myth. Bulbophyllum can still be overwatered.

They may like a good amount of moisture for their pseudobulbs to remain plump, but the roots still need a good amount of air to them. They can dry out completely for up to 2 -3 days, (sometimes as much as 1 week, depending on the circumstances), without any signs of distress before needing to be watered again.

If you mount them, then, yeah, they'd more than likely need to be watered everyday, particularly if the temperature where you have them growing is warm. Even then, they can still dry out for days before you'd see signs of distress.

Overgeneralizing about temperature requirements for Bulbophyllum species is also not a good idea. Not all Bulbophyllum species like it warm, (contrary to what you may have read or have been told). Some species definitely do like it on the intermediate to warm range of temperatures, but there are also a good number of species that are just fine growing under intermediate temperatures. Temperature range tolerance within a genus of orchids can differ between species because it is a function of the differing habitats in which they are found and the temperature range that occurs in those areas. While it is still possible to make some generalizations about temperature range tolerances within a genus of orchids, be cautious to not OVERgeneralize.

For example:

Scenario #1: If Bulbophyllum sp. 'A' cohabits the same geographical range and same sea level of elevation as Bulbophyllum sp. 'B', despite being in slightly different ecological niches, they are going to have similar temperature tolerances.

Scenario #2: If Bulbophyllum sp. 'C' is found in country 'A', but Bulbophyllum sp. 'D' is found in country 'B', however, they are found in very similar ecosystems and are present at very similar elevation ranges that experience very similar temperature ranges, then of course, both species would have very similar temperature tolerances.

Scenario #3: However, if Bulbophyllum sp. 'E' is found in a completely different country, (for example, country 'C'), and country 'C' has a completely different climate than countries 'A' and 'B' from the previous example, and it is found in a different kind of habitat at a higher elevation than where Bulbophyllum spp. 'C' or 'D' comes from, then Bulbophyllum sp. 'E' would not have the same temperature tolerance as Bulbophyllum spp. 'C' or 'D'.

The temperature range of 64 F - 70 F is fine for the 2 species you have, it falls within their range of tolerance. I have some of my warmer growing Bulbophyllum in that temperature range and they are growing. For the 2 species you mentioned, I would caution against the temperature dropping below 60 F, especially at night.

If you have these orchids growing in a pot where you can't see the roots, then, I'd recommend using a wood slat basket as an alternative. Wood slat baskets will still be able to hold in the potting media while providing far better air circulation to the roots and allowing you to see at least some of the roots and what is going on around the root zone.

Orchids have what are called adventitious roots in botany. The roots are not functionally meant to grow in a way that allows them to grow all that deep into whatever it is they are growing on/in. Instead, the roots are meant to cover more surface area than depth. What I'm getting at is that the deeper the pot is, the more problematic it is for your orchids, particularly for something like Bulbophyllum where they don't necessarily grow a whole lot of roots per growth. The reason is that there is a higher probability that there are a lot of spots inside the pot where the potting media can retain a ton of moisture that doesn't either get used up by the plant or evaporate into the air. These wet spots can cause problems with root rot because they keep that part of the potting media too wet and end up suffocating the roots.

I hope this gets you on the right track to growing Bulbophyllum. They're really cool orchids. And maybe, you'll end up with a large colony of them, who knows.

[plantzzzzz]

There are actually many Bulb. species that require it cool to cold.

Here are two, from PNG:

IOSPE PHOTOS

IOSPE PHOTOS

They grow at the same elevations or higher than D. Cuthbertsonii.

[Spotted Milti]

This is such great info, King! Thanks for taking the time to respond. I'm happy my bulbos are in good shape so far and that the temps are okay for them. This is about the coldest Georgia really gets inside my house, so we should be okay through the winter

Good to know that they're more tolerant of drying out than I originally thought. I've been keeping up with the watering every 2-4 (5 days when it's especially dreary) and their pseudobulbs show no signs of wrinkling yet!

[estación seca]

They will not tolerate drying out when they are pushing new growths, perhaps unless they are large plants.

[WeirdGuySeattle]

I find my bulbos go downhill fast when you have wet combined with cold.

They have pretty short roots, so can take a lot of water without burying in to stanky media - their roots are mostly on the surface (seems like).

But then again, I have a few bulbos that don't flower for me - so take that for what its worth. I've killed as many as I've had flower for me.