Disease or sun bleaching?

[Lorax7]

I’ve got an Albizia saman tree that’s got leaves turning white around the outer margins, but there also appear to be some little brown dots as well. It’s being kept indoors under an LED panel. I’ve got 3 other trees of the same species under similar lighting conditions and they’re all looking healthy. So, I’m wondering what’s really going on.

 

[Warpig]

My uneducated guess would be a nutrients deficiency. I haven't seen this before so will be watching to see the other answers you might get. What kind of soil/fertilizer do you use for them?

 

[Wires_Guy_wires]

Chlorotic leaves can be caused by a lot of things, though the cause is always pretty limited.
I don't see the typical bleaching I see with LED. So I'm going for an iron deficiency. But iron is usually not needed a whole lot and most soils contain enough of it for a healthy plant.
This means that you've either washed it out by means of low pH water, or locked it out by overwatering or locked it out by using too alkaline water.

Usually, when the signs are ambiguous, it's a case of overwatering. Since the rest of your plants don't have the same issue, I'll put my money on overwatering. It's very likely that not all of the pots and soil blends are precisely the same, and with a steady water regimen, this can cause issues for the least free draining ones.

A foliar spray with micronutrients could help it restore faster, but allowing the soil to dry in between waterings needs to become part of the routine too.

 

[0soyoung]

I think it got too dry a week or so ago. Desiccation proceeds from the margins toward the petiole which is pretty much the pattern in your leaves.

 

[Brian Van Fleet]

I think it got too dry a week or so ago. Desiccation proceeds from the margins toward the petiole which is pretty much the pattern in your leaves.

Ditto...

 

[AJL]

Dessication and possibly Red spider mite damage?

 

[Wires_Guy_wires]

I think it got too dry a week or so ago. Desiccation proceeds from the margins toward the petiole which is pretty much the pattern in your leaves.

When my albizia's go dry, they stay green and crumble up. Then they grow new foliage with no discoloration.
I see a sandy soil and a bunch of moss. Indoors, that's usually a troubling sign.

I'm not saying you're wrong, I'm just motivating my own conclusion a bit more. If it was too dry, the discoloration should stop spreading. If it is being kept too wet, the discoloration might continue to spread.

@Lorax7 could you tell us how it's doing?

 

[Lorax7]

When my albizia's go dry, they stay green and crumble up. Then they grow new foliage with no discoloration.
I see a sandy soil and a bunch of moss. Indoors, that's usually a troubling sign.

I'm not saying you're wrong, I'm just motivating my own conclusion a bit more. If it was too dry, the discoloration should stop spreading. If it is being kept too wet, the discoloration might continue to spread.

@Lorax7 could you tell us how it's doing?

It doesn’t seem to be getting worse and it’s probably too soon to tell if it is getting better. You are correct that there is indeed some coarse-grained Akasha sand in the soil mix on that particular tree (along with pumice and lava rock, if I remember correctly). The moss I deliberately put on there, some grown from a packet of spores and some more developed chunks pulled from a separate container that had been growing for a while.

 

[sorce]

I'm going with overwatered. The trunk has enough algae to eat thru all the good tissue.

Close second for a gang of them death balls blew out an s-load of nitrogen.

Sorce

 

[Lorax7]

I'm going with overwatered. The trunk has enough algae to eat thru all the good tissue.

Close second for a gang of them death balls blew out an s-load of nitrogen.

Sorce

Death balls?

 

[sorce]

Death balls?

You got balls....

If you use this garbage. Time-released, green balls. Let's explore side A of fresh Nursery Mugo. Mmmmm! Lets see what happens when some balls get in the side of the pot and the sun heats them so that they all open at once! Black Death! Yuck! So before these over the good side open....and...

www.bonsainut.com

Sorce

 

[Lorax7]

You got balls....

If you use this garbage. Time-released, green balls. Let's explore side A of fresh Nursery Mugo. Mmmmm! Lets see what happens when some balls get in the side of the pot and the sun heats them so that they all open at once! Black Death! Yuck! So before these over the good side open....and...

www.bonsainut.com

Sorce

Hmmmm. This is the stuff that I’m using (but only during winter when the tropicals are indoors).



I use all organic when the trees are outside. I don’t use organic fertilizers indoors because I don’t want the house to smell like a barnyard. What do you use indoors for the winter months (or do you just not fertilize while the trees are inside?

 

[sorce]

not fertilize

I've been thinking about that recently, since I haven't been fertilizing.

I'll usually fish em in the winter too, but I haven't had it close, I may notice effects I'm spring, doubt it! Eh...my ecosystems function without fert over winter! Found some baby centipedes today, certainly have worms in em.

I wouldn't trust those balls.
Any Balls.
They're all made off the same "time released" principle that isn't actually possible, which leads to malfunction.

Sorce