New to Neo questions (air roots, rock mounts, watering, light)
 

I am new to orchids (not new to horticulture) inspired by some Neofinetia falcata that I happened upon at Young's Plants in Delta, BC (and transported 2 Neos and one Sedirea japonica home to Toronto, Ontario). In particular I was inspired by laval rock mounted orchids, though I am now familiar with the moss mound technique as well.

I have been doing copious reading, but wanted to ask a couple specific questions to gather opinions.

I wanted to repot the orchids from their cramped and algae encrusted plastic pots and attempt a coupl rock mounts.

The rock mounts turned out ok, but I have questions:

Why does one traditionally wrap and cover the air roots? I find them to be aesthetically pleasing to be in the air (other than the ones used for support), in a bonsai fashion.

Is it necessary to use cotton thread in order to help wick water up towards the plant and growing media (I have mine mounted on the rocks in spahgnum, with some spahgnum trailing and some added moss, which gives a nice natural look - but I couldn't quickly find good lava rock - so they may need to be remounted).

How much light should I be giving them? I have to supplement a Northwest facing window with artificial.

How much water? Generally how much fertilizer (types and when)? I am mostly watering with Orchid Champion. My understanding was that these tend to like to be wetter, but....

Now both Neos appear to be growing, particularly obvious from the air root growth, tips of which are pink or red. But one Neo's leaves are much lighter or yellower in colour in places (this one is also older with more "chicks" - I appologize for not knowing the terminology yet). Is this a concern? The younger smaller one is greener in colour.

Is there any book or online reference to rock mounted orchid culturing? Particularly for the smaller orchids?

Since repotting the Sedirea (into a sphagnum ball) its lowest leaf has begun to yellow from the crown outward and is obviously going to fall off. Should I be concerned?

I'm wondering exactly how to give these little gems the best kick start (i.e. conditions) I can without a greenhouse to get them happy and healthy. (I was thinking about putting them in a fish tank to raise the humidity / warmth...)

Many thanks for any suggestions!

(And yes, I will post pictures as soon as I can.)

aerial roots are not traditionally wrapped, although the older, leafless part of the stem, along with any roots on that part, may be wrapped in sphagnum. it is very important to maintain airflow around the roots at all times, so they must not be wrapped tightly, and the media must drain well.

the sphagnum should keep enough moisture near the roots, there's no need to add anything else

medium shade is good, about 2000-3000 foot candles

let them dry out slightly before watering. fertilize weakly about once a week.

new growth is always a good sign - new roots generally indicate that humidity is good. pink or red root tips indicate good light levels - lower light levels will result in green root tips.

by "chicks" do you mean smaller leafy growths? those are just called growths. Yellow spots on leaves may be "tora-fu" or tiger stripe variegation, or could be signs of sunburn. post pictures, and I'll let you know what it is.

none that I know of. an important thing to remember is that certain types of rock - lava rock in particular, will retain moisture and minerals very well. it's very easy to over-water or over-fertilize when you have plants mounted on lava.

that's a huge cause for concern - old leaves generally yellow from the outside in, yellowing from the inside out can be an indicator of crown rot, and may be a result of overwatering. as with neofinetia, sedirea requires good airflow around the roots, and a well-draining medium. remove the sphagnum, and check the condition of the roots and stem. it could just be a problem with the leaf, but it's better to check and make sure.

do not keep them in a fish tank - both species require good air flow, and usually do not last long in such conditions. post pictures when you can, it will help us to identify any problems there might be - or figure out that there aren't any problems.

Thank you for the helpful reply lambelkip!

It seems to me that the traditional Neo sphagnum moss potting method has the aerial roots re-wrapped and put inside the pot. I was asking more from an aesthetics point of view (ie. is it that it is more traditionally aesthetic to hide the aerial roots?)

I have posted pics of my new rock mounted Neos (the one bigger than the other one is the one I am concerned about, its leaves are more yellow - I can't tell yet if they are getting more yellow, but it was purchased this way and emphasized to be healthy and a good bloomer.

This is the one (the pictures make it look a bit greener than it seems to the naked eye): http://www.orchidboard.com/community...s/P1020772.JPG

And this is its growing aerial roots (many red tipped): http://www.orchidboard.com/community...s/P1020775.JPG

More pics in the Gallery: webSherpa Orchid Gallery

Here is the Sideris that has now dropped that yellow leaf. The terminus looks clean and dry where it fell off with veins terminated. When re-potting I did use clean scissors (sharp, sharp dressmaker's snips) to cut off some dark rotted roots (but there were also still many healthy roots):

http://www.orchidboard.com/community...s/P1020768.JPG

Tried to take a close-up: http://www.orchidboard.com/community...s/P1020777.JPG

More images in the gallery. webSherpa Orchid Gallery
Comments and hints welcome. :biggrin:

I love your rock mounts, very unusual.

Marilyn

Lava Mounts:
 

Your mounted furan on the lava do look nice. Kip has given you some very good information. I would also add that furan means "wind orchid" in Japanese, in case you don't yet know? The reason that I mention this is because I feel that you are headed for possible trouble due to lack of air flow to your root system. Furan love and need good air flow. The furan pots were designed with this in mind. From viewing your photos I would reduce the size of your moss mound somewhat and be sure and have a fan going 24x7. Like Kip said, lava holds a lot of water, I use it in my humidity tray for this purpose. So with lava holding water, a large moss mound, and little air between the rock and the roots of the plant, root rot is very likely to occur. I don't know if you have a hole in your lava stone, like is done with bonsai, but this would also help.

Wish you the best,

Fuukiran:
 

Hello Kip,

I have a question if I may regarding your statement concerning red and green tip roots. You indicated in your post that lower light produces green tips, while higher light red tips. I agree and have noticed the same thing. I have however seen many green tip rooted plants flower out nicely. Has this been your experience, or do only your red tips flower? Do you find that green tips are produced with 2K foot-candles and red tips at 3K? I have also been told that the genetics is also a factor in determining green tip from red tip plants? What are your thoughts?

Thanks,

steve, most varieties have green root tips, regardless of light levels. the varieties which have other colors of root tips will only produce that color if the root tips are getting enough light. if the roots are buried in the medium, the tips will usually be green. I've never measured the light levels in my growing area, so I really can't comment on specific light requirements. I only know how to recognize when they're getting too little or too much light.

I can't comment as I've never tried a rock mount, but I just wanted to say they look beautiful mounted that way!

Makes me want to try it, too bad I have an idiot cat that likes how they taste. I would be able to leave them out like that.:biggrin:

Fuukiran plants retain their root-tip color if they are a true representative of the variety. They may acquire a 'tan' of sorts (like a reddish flush) if subjected to high light or deep cold but green-tipped rooted plants stay green-tip rooted plants, ruby-tipped rooted plants stay ruby-tipped rooted plants etc etc.

Thank you for the kind comments. I prefer this mount too because of its relationship to bonsai.

I guess my biggest concern then is the yellowing of the Neofinetia leaves (I am so used to "green" meaning "good") that I am struggling with thte concept of the leaves being a bit yellow. However, I have noticed them yellowing a bit more (in both plants) and wondering if I have too much light (1500 - 2000 ftcandles for 12 hours), or if its transplant shock, too much watering (or too little).

This is not lava rock they are mounted on, it is ontario granite, so its not particularly porous and doesn't retain water. I have seen the Neos mounted on less porous laval rock and the rock stayed wet all the time. The Korean grower said that the moss should remain moist, though not soaking.

There is a very thin layer of sphagnum under the Neos and then some layered on top. The plants are held to the rock with thread (I used polyester thread, but likely I should have used cotton as in addition to holding the plants on to the rock, it would appear that the threads also wick up water from the dish below each plant - in mine however, the polyester thread does not readily wick water.)