Red bulbs! how had is this?

[viper]

Like all my other orchids my new Dendrobium orchid is living outside mounted on a log with some moss. it lookes healthy apart from the fact that one of its bulbs has started going sort of a redish colour.

what does this mean? is it bad?

[pikevi]

I just have the basic knowledge of Botany, viper.

But appearence of red pigments in 'usually' green plants is due to depletion of chlorophyll. Almost all plants have many pigments (anthocyanins,in this case, which is the red pigment) and many others. But chlorophyll will mask their expression. When the amount of chlorophyll is reduced( as in fall season) the other colours show.

Some chemicals and reduced oxygenation of the roots also can cause a reduction of chlorophyll production.

I am not sure if it is something other than adequate lighting in your case. May be some dendrobiums do exhibit redness. Check the amount of light it receives.

I hope someone will help you more.

[cupcake]

Too much direct light? Lets have a photo please.

[mayres]

I have a dendrobium that is blooming like crazy currently that has turned almost completely red - canes, leaves, everything - flowers are pink - it has had the light levels pushed to the limit. I think if I would have given it one more footcandle of light it would have been toast? This is culturally living on the "edge". mike

[viper]

my orchid isn't getting that much light.

is the redness bad?

[pikevi]

I would have assumed less light would cause the red pigments to show. May be there is another mechanism in place in some orchids to synthesize more red pigment to reduce the load on chloroplasts.

I hope some one can explain that phenomenon.

[mayres]

I have a number of genera that turn reddish with high light - it is especially pronounced in plants that have pink, red, or reddish purple flowers. I also have some intergenerics where the pseudobulbs turn a darker red than the leaves - I wouldn't worry about it.

[brookn]

I have noticed this also when I am pushing the light levels. I turned a new growth on my dend almost completely red, I gave it less light and it kept some of the red and the rest went back to green. Mike I would say you are definitely pushing the limits!

[tom499]

Maybe worth lookin at some photos of spider mite damage, but if theres no other symptons Its probably just light level changes.