Little Lost - Losing Leaves

[kmccormic]

Hi There!

I have 2 dendrobiums. I recently repotted them (and my whole 10-plant collection) 2-3 weeks back, because I thought I might've had bugs in the mix- some plants had bugs, not all. No more sign of bugs. The mix is lecca, small stalite, bark, some charcoal, and lots of small perlite, because that's what I could find locally. They've been losing leaves ever since. I tried watering one more frequently and the other less frequently, still yellowing leaves, and no new leaves developing. I'm not sure if, with the new mix, I'm under/over watering, or if this is potentially a biological cycle thing?

Dendrobium victoriac-reginae x sib
Dendrobium lawesii (red and yellow x red)

Could you tell me if this is their "winter rest" now? I'm in the US, I'm not sure if their time schedule is southern hemisphere. Are they deciduous? Evergreen? Type I? Help! I'm not averse to starting over, but I can't even tell if they're dying or not.

Regards,
Kara

[kmccormic]

Some before and after photos. The lawesii when I bought it, then a week after repotting, and 2 pics from now.


The victoriac reginae when I bought it, a week after repotting, and 2 pics from now.

[Wynn Dee13]

I just visited Andy's Orchids and he told me Den lawesii likes to be kept moist. It's on my wish list but his are mounted and I didn't think I could keep it moist all the time so I didn't get one. Maybe the new meadium isn't giving the plant enough moisture. I also read online both these species like to be grown in small bark or sphagnum moss. Your lawesii looks really dehydrated.

[kmccormic]

Thanks Wynn-I finally found someone locally who sells new zealand sphagnum moss. Think I should just toss it's current mix and repot? It's only been a few weeks in the new mix...

[WhiteRabbit]

It's been my experience that many Dens will 'pout' after repotting. I don't know if that's what's happening.

Both of these do like to remain moist.

Victoria-reginae, at least, will shed foliage (I don't know about lawessi) - BUT would seem unlikely at this time. It doesn't matter which hemisphere a plants origins are in, they do there thing by which SEASON it is, not which month (they don't read calendars)

You could use a skewer in the media to help monitor the moisture. New bark will not hold moisture long, and needs more frequent watering for a while. I don't know if you used medium or small bark chips ?

[Wynn Dee13]

If your good with moss I would use straight moss but some people have a hard time with it. If you use it by itself pack it loosely and put something in the bottom for drainage. I use styrofoam packing peanuts in the bottom of the pots. You could also cut some of the moss into one inch or so pieces and mix it in the medium you are using. Use whatever you feel more comfortable with. I really like moss but some people hate it. Sphagnum moss is also good for getting roots to grow then if you don't like using straight moss you could repot into your mix with the chopped moss when you see new root growth.

[WhiteRabbit]

How much light do these get? What temps are they growing in?

[Daenerys]

I'd love to get an answer to this one too.

I killed one den victoria reginae over this last winter. It started the same way: losing leaves. Then a new growth started, and promptly rotted away. I know in my case it was not a root issue, because the roots were wonderful.

Now I'm on my second den victoria reginae, trying to avoid my early mistakes, but it's also losing leaves. Maybe it's a temperature issue? I'm in NYC with no airconditioning (yet) so it's definitely been warmer than they, or I, would prefer.

[kmccormic]

Hi Sonya:

It's a home south-facing windowsill setup. The lawesii gets some direct sunlight for a couple hours in the morning. Otherwise, they both get indirect sunlight, and a fan blowing lightly in their direction during the day. I'm in MAss, United States. I do have some AC, in another room, so temperatures tend to be in the 70's, even at the hottest part of the day. The lawesii is next to some thin-leaved oncidiums also getting direct light in the morning, and they don't have any sunburn on the leaves. I had been deliberately watering the victoriac reginae only once per week try to see if I needed to increase or decrease watering.

All I could find (not a planned repotting session) was large bark, which I manually chopped down to smaller pieces - mostly medium sized I think. I thought the lecca and stalite might have helped water retention with new bark. I may have to bite the bullet and repot in sphagnum, but I kill things in sphagnum, so that has me nervous. The lawesii is in a tiny 2-inch pot.

[WhiteRabbit]

hmm - well I do think that the once a week watering may not be sufficient - but can't say positively without being there hehe.

I'd definitely use a skewer (bamboo skewer for kabobs) in the media (gently twist skewer into media about midway between center and rim of pot, or wherever you can, just not right at the rim; leave it in there for half an hour-hour - I leave mine in all the time - to check for moisture, pull out the skewer and touch to your cheek or upper lip; if it even feels slighlty cool there is moisture in the media, but these don't want to dry out, so you should water at least by that point, just don't need to water if skewer feels wet wet, or very damp; put skewer back into same place as it was) - or you can use a freshly sharpened pencil, tho don't leave that in the media - twist it down into the media, wait 5-10 minutes, pull it out. You can see if the newly exposed wood looks damp or not.

If you have leca, you could pot into straight leca, and leave the pot in a saucer with water (passive hydro). I grow my victoria-reginae in a combo of perlite and pumice, and in summer leave it in a saucer with water, tho I let all the water be gone from saucer before watering again. In winter I water less and don't leave water in the saucer, but mine is outside in the cool damp weather.