Cattleya new growth turned yellow

[boni112]

My cattleya orchid has three new sprouts. Two are growing normally but other one has developed yellow foliage.what is the possible reason for this?

[SouthPark]

Hard to say what the cause is right now. But from observations ----- this orchid is mounted on a block of wood, right?

How long have you had this orchid for roughly?

It's possible that it might not be getting enough water into the plant in order to support all three growths. It probably depends on how much water it is able to get.

Also ------ one of those green coloured leaves has reddy-brown colour down toward the base of the leaf. Is that red colour pigmentation? Or is there an issue with the leaf down at the base?

If the red tinge is due to high level of light, then that's ok.

[Orchidtinkerer]

the red tinge is a sign of a nutrient imbalance(wrong PH - Nutrients can't be absorbed efficiently) and the yellow growth has died so it all points to your wood block decaying and causing a highly acidic environment killing off the roots. That block of wood needs to be removed.
It will cause a lot of root damage, those blocks of wood are terrible for potting but you will have to deal with it sooner rather than later.

[Roberta]

Boni...
Do you have a way of measuring the pH of the water running out of the pot? pH paper is inexpensive, and easily obtainable at a hydroponics store. The reddish tinge of the leaves I would first think of light being near the upper limit of what the plant wants. The loss of the growth would suggest that taking it out out of the pot and checking roots would be a good idea.... if roots are healthy the plant will recover from other insults. (I think I see surface roots that are black... not good. Could be tannins from the wood, or rot) If not, you need to work on the environment for them (better medium) I have never had an orchid die from nutrient deficiency (I fertilize very little, sometimes don't get around to it at all, and they grow very well) However, a very acidic environment from tannins from rotting wood can certainly kill roots...But if you're losing roots for whatever reason, you need to correct whatever is causing it - without roots the plant not only can't take up nutrients, it can't take up water either. So a photo of the roots while it is out of the pot could tell us a lot.

[rbarata]

I can't understand what medium is that...but the way it looks doesn't match the one expected for a Cattleya...unless it's a piece of wood.

[boni112]

Hello everyone..it is mounted on coconut husk not wood. It is farm and hard not mushy like older and decaying one.I have this orchid around 2 1/2 months approximately. I think It is possible that it isn't getting enough water as I keep it under direct sun in the morning and afternoon.those red colour are most probably pigmentation caused by high light. I use ro water with lowest tds possible (10-15ppm) and then I add fertilizer to it any try to keep it under 100 ppm.I have never measured pH of water running out from pot. pH imbalance may be possible as Pure ro water has no buffering capacity so adding fertilizer can raise pH of the water. I have pH test kit for measuring aquarium water parameter. I will measure pH of fertilizer solution but it is difficult because I don't have fertilizer mix and use only one salt in a day ( like cano3 on Monday kno3 on tuesday..I use Mgso4 rarely just to provide sulphur. For magnisium source I add Mg-EDTA and for micronutrient I give EDTA micronutrient mix).I don't know why and when the roots turned black maybe long time ago but they are not soft.I will attach images of roots from different angles

[SouthPark]

True. It's possible that the sun was just drying the catt out, and it couldn't support all the growths. Just a possibility.

The nice thing is that there are those green colour roots. They look ok actually. The tips on them are black coloured or dark ....... but as long as you keep watering satisfactorily, and if those roots keep growing ----- then all should be ok.

A pH check will be nice too ----- I agree. Roots not soft is a good thing as well.

[Orchidtinkerer]

Originally Posted by boni112

Hello everyone..it is mounted on coconut husk not wood.

Lol, that is a block of wood. It is raised out of the net pot and has wood cracks. coconut husk would crumble out of the net pot.

[estación seca]

Very high light can bleach new growth yellow like this. If the growth is yellow and still firm I think that is the problem. Most people in warm climates need to provide some at least a little shade to Cattleyas during to hottest part of the day.

[fishmom]

"Lol, that is a block of wood. It is raised out of the net pot and has wood cracks. coconut husk would crumble out of the net pot."


I think that is the firm coconut shell used for a mount, not the shredded husk product we see in the U.S.