Dendrobium speciosum leaves yellowing from tips

[nolaorchid]

Hey guys. I'm rehabbing a gift D. speciosum and in less than two weeks the few remaining leaves have begun to yellow and die. I'm told this problem has been ongoing. The yellowing starts at the tips, then spreads to the whole leaf and they eventually brown and drop.

It was kept pretty dry until I received it, and I have since watered it twice, hoping to plump the pseudobulbs a little. It's being kept in a spot with all-day bright indirect light with a bit of direct sun in the morning. It's been very hot here lately, in the mid 90s F every day/ upper 70s and low 80s at night, but still humid and breezy.

It has one strong new growth, but even the sheathing leaves on that shoot seem to be yellowing. It's not rotting from what I can tell, but I'm defintely being cautious about over-watering. The roots fill the pot pretty well and it seemed perfectly capable of recovering until the yellowing happened.

It's potted in mostly coconut husk and I'm almost wondering if salts are present and building up in the leaves. But I don't want to repot it now with the new growth emerging. The yellowing is progressing pretty fast, so I may just be out of luck.

What do you guys think? Should I repot? Flush the pot with tons of water? Take it inside away from the heat?

Any help is much appreciated!

PS. I'm posting this from my phone, so I'm hoping the pictures turn out ok.

[No-Pro-mwa]

Welcome to the board. When you see new growth that is the right time to re-pot. I have just started with the Auzzie Dens and only have 2 so far. They are in 3 and 4 inch pots and I water them almost every day. If I skip a couple of days it is too much. I blasted buds on the 3 inch both of them. and the second one I don't think I skipped more than 1 day in between.

Yours does look dehydrated so maybe it needs more water. Hopefully others will chime in.

[nolaorchid]

Thanks for the welcome! So glad to know about the repotting timing. I think I'll get it in to some fresh media. I'm new to Aussie dendrobiums too and am still figuring out their culture. It's not happy, whatever the cause.

[estación seca]

Welcome!

As Shannon wrote, D speciosum, its Australian relatives and their hybrids need a lot of water in the growing season. My species plants and hybrids also dry out in 1-2 days this time of year.

Do you know what the roots are like below the surface? If the medium is old, definitely repot into something that drains well. I would think coconut husk retains too much water for your humid, rainy climate, but I might be wrong.

My plants are in a bark/perlite mixture.

There is cultural information on Australian Dendrobium hybrids in the link below. It also applies to the species.

Growing Aussie Dendrobiums

[nolaorchid]

Thanks! I've been looking for a good care article like that! Checked the media and it's basically in soil at this point, but there are roots to the bottom. Glad it's the right time to repot anyway. I'll mix up a much better draining mix. Hoping I can conserve at least some roots in the process.

[AJW]

Re pot. Consider using pine bark around grade 3. These Dens. like plenty of air around the roots. When you are watering water the plant medium not the plant. A part of its growth treatment mix up a weak dose of Epson salts 1 table spoon to around 1 gallon or 4 liters of water. Water the medium first then apply a coupe of cups of this mixture if you do that for a couple of times you should start to notice some positive change. You can use this mixture on any plants at the start of their respective growth cycle.