Orchid Culture Questions and Answers
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Questions and Answers from 2017
by Sue Bottom, from the St. Augustine Orchid Society Newsletter
Email us with any orchid question, if we can't answer it we'll find someone who can! Send photographs too!
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Enlarging Rings on Orchid Leaves


 

Enlarging Rings on Orchid Leaves

Q. I have these rings on a Gongora, as well as two other orchids. It starts with one leaf, I cut it off and later on, other leaves develop the same problem. I thought it might be the sun at first but I remember reading that circular patterns are a sign of virus. Should I trash these 3 orchids fast?

A. I don't think that's a virus, it looks like classic Anthracnose, that is caused by one of the leaf spotting fungi. You should be able to see tiny little dots in the discolored area, those are the spores that spread the disease. You can remove the diseased leaves to a closed container. Fungicides can be sprayed to help prevent spores from settling on leaves and spreading the infection. More air movement and less leaf wetness will help prevent the conditions that favor the disease.   (Jan-18)


White Crystalline Material on Potting Media
 

White Crystalline Material on Potting Media

Q. What is this white stuff all over my lava rock? I am repotting cause so many roots were growing out of the pot on my oncidium.

A. Quite a mystery! It's not snow mold. That grows on organic media, and this substance is crystalline. You might think salts precipitated out of the water, but then why are the roots so healthy,with none of them burned? Courtney says there are some bacteria that make colonies and use dissolved minerals as an energy source. The white material, possibly calcium carbonate, dissolved when dropped overnight in a solution similar to vinegar. It doesn't seem to impact the health of the plant. Just another of life's little mysteries!   (Jan-18)


Oozing Spot on Phalaenopsis
Oozing Spot on Phalaenopsis
Oozing Spot on Phalaenopsis
 

Oozing Spot on Phalaenopsis

Q. Someone just gave me this orchid and I canít identify its problem. Can you help identify it and give me some treatment options?

A. The bottom leaf has soft rot, that leaf should be removed immediately. If the rot travels to the crown it will kill the plant. The upper and lower surfaces of the other leaf looks comprised as well. If the plant has enough other leaves to sustain it, you might consider removing that leaf too. Then get a fresh bottle of hydrogen peroxide, or better yet one of those spray bottles of peroxide that Walgreen's sells, and spray all the above ground portions of the plant, particularly around the crown where the rotting leaf was. If you were just given the orchid, then you don't really know what happened to it before that allowed the rot to get to the plant. You'll just have to keep an eye on it to see if you stopped the rot in time. If you're a cinnamon person, you could dust the crown of the plant and around the cut edges after the peroxide dries. The cinnamon will dessicate that portion of the plant and create a barrier so bacteria can't invade.   (Jan-18)


Phal Leaf Didn't Open
Phal Leaf Didn't Open
 

Phal Leaf Didn't Open

Q. I rescued this tiny Phalaenopsis about four months ago. It was dehydrated due to total root loss other than 4 small aerial roots. It has shown some improvement, the leaves are no longer limp, and it has managed to grow two more aerial roots. I am not sure if there any new roots growing in the media yet. It also started to grow a new leaf about 2 months ago but it has shown no signs of opening up by now. Why?  

A. Your plant is going to be fine. I like your mix, the addition of sphagnum moss to the bark, that will help hold a little moisture cause bark oftentimes is hard to get hydrated when you first put it in the pot. The mix looks perhaps a bit dry, are you growing indoors where the humidity is low? Are you watering once or twice a week? One thing you can do is put a thin layer of sphagnum on top of the pot to help hold a little moisture at the upper end of the pot where the tender new roots will form. If you just repotted and the leaves are starting to lose their leathery look, I'd say your plant is well on its way to recovery. Make sure it's getting enough water and it'll come out of its holding pattern and the leaves will start enlarging. A few weeks later Alicia wrote back, "Good news! The leaf is now open!"   (Jan-18)


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