Sunday, March 25, 2007

Why Are My Orchid Leaves Turning Yellow?

by Rob Roy

This month I want to talk about yellowing orchid leaves. There are many reasons why leaves turn yellow. This is a common question that we receive. Orchids like all other plants age and during that aging process the older leaves will turn yellow and die. Remember we are saying the older leaves of the orchid plant, those toward the bottom.

Let's turn our attention to leaves that are not old and not on the bottom of the plant but newer leaves on the orchid. Some of the other reasons include: 1. Bacterial or fungal disease 2. Too much light 3. Too much water 4. Enviormental

Bacterial or fungal disease on orchid leaves will show itself as irregular yellow spots on the leaf. In other words it will not involve the whole leaf but just spots on the orchid leaf. If there is a black growing edge to the yellow spotting then this is caused by a fungus.

The treatment for the bacterial infection is with Physan which can be purchased at a nursery. For the fungal infection a fungicide for plants or orchids will do fine.

Yes, yellow leaves on orchid plants can be due to too much light. In fact, in the mid day summer sun orchids can actually get burned spots on their leaves. This may be one of the more common reasons for yellowing of leaves.

Place the plant in indirect bright light for a while and it will recover just fine. The leaves will remain yellowed and will not turn back to green.

Although, not usual, too much water can will also cause the leaves to turn yellow. But in addition there will be evidence of "rot" as well. Too much watering can cause a fungal infection and this is seen with black areas within the yellow area as seen in this picture.

Stop watering for a week or two and then only once a week after. You need to treat for a fungal infection.

What sort of enviormental issues cause yellowing of orchid leaves? The biggest is cold weather. Yes, when orchids are sbject to cold weather their leaves can turn yellow due to the damage caused. This can affect the whole leave(s) or parts of them.

Also, certain enviormental toxins can create this condition such as paint fumes or cleaning fumes. When these are being used be sure to get air circulation moving around the orchids.

As you can see there are quite a few causes of yellowing leaves. Treat the easy ones first unless you suspect a more serious problem like a fungal or bactierial infection. If you have questions consult a good nursery or your local orchid society.

Resource and Bio: Get the orchid guide, Mastering Orchids, a 70 page guide for half price ($9.95) Plus a 15 % discount on an orchid. Just subscribe to our monthly free orchid newsletter, Orchidaceae. http:www.orchids-plus-more.com/orchid-newsletter.html

This site http://www.orchids-plus-more.com is devoted to these wonderful orchid plants. Did you know they are the second in popularity only to the poinsettia plants? You will find a good deal of information on how easy orchid care really is. They are wonderful to have around your home or for that special gift. Orchid flowers are beautiful and can last for years. Your plant will be appreciated for years and years.

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About the Author

This site http://www.orchids-plus-more.com is devoted to these wonderful orchid plants. Did you know they are the second in popularity only to the poinsettia plants? You will find a good deal of information on how easy orchid care really is. They are wonderful to have around your home or for that special gift. Orchid flowers are beautiful and can last for years. Your plant will be appreciated for years and years.

The article may be reproduced

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3 Comments:

Blogger Jessie said...

thank you this was very helpful! i really appreciate your input.

7:04 PM  
Blogger Dominique said...

Dear Margaret,
I have a phal that I've had for a year now. It is in bloom and was healthy but I think the cold is getting to it, as all of the leaves have taken on a light green to yellow hue. Obviously concerning. I have high ceilings in my house, so heat rises despite turning it up. I move it away from the windows at night in case of microclimate exposure, but what do I do about it not getting enough heat? Can I put it on a heating pad periodically? Advice appreciated.
--Dominique

7:23 AM  
Blogger Shirley Lowe said...

This is great info thank you. I've been growing orchids for a few years now and have a collection of about 85 orchids. It's just today that I realized two of my orchids have some fungus infection. I feel like I have to go buy the fungus treatment like as if it were a child with a fever. Lol.

5:58 PM  

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