As a guess, I don't think nutritional, but disease. Compare to Cephaleuros virescens for one...these are said (hort.purdue.edu) to sometimes have issues with Cephaleuros virescens, algal leaf spot and green scurf, and also Phyllosticta leaf spot.

Yeah I agree with morz8, it's probably not a nutritional problem. Actually, to me it almost looks like some kind of scale insects. Notice how so many are located along the veins, where the water and sugars are being transported.

Art

Looks like edema (oedema) to me. The most common cause is when the plant takes up more water than it can transpire. The inner cells enlarge and swell, blocking the stomates (guess where the majority of those are located). If the condition persists, damaged or burst cells actually evolve into the cork cambium associated with bark.

Edema may be common in locations where there is ample moisture in the soil (not necessarily too much) but the atmospheric conditions not conducive to high levels of evapo-transpiration. Cool air temps, high humidity, cloudiness, and other factors can contribute to edema. It also occurs quite often on indoor plants.

Other environmental factors can cause edema, but I'd have to look those up and I'm not going to do that right now, lol. Foggy brain at 4:25.

Anyways, I think it's edema.....that's my story and I'm stickin' to it! :-)

what is its 'culture'??? as in plant culture ... rhiz.. define that for the OP ...

you have explained the symptoms... but you have given us no background on its situation ... other than you think its water related ....

potted??? in the ground .... full sun ... wind... heat extremes??? ...

how in the world did you get to water as the root issue ... of which.. i doubt highly ...

if it is a water issue.. then i would think its potted.. and its a MEDIA issue.. ITS holding whatever is in the water... to toxic levels.. ergo.. the fix would be to change the media ... etc ... AND THEN FIX THE WATER ...

presuming your name indicates san fran ... in my MI world.. its the garden center of the world... and defaulting to water.. just doesnt seem right ... but that is a gut reaction.. and sometimes my gut lies to me ... lol ..

so .. how about you round out the facts.. the situation.. its culture for us ... and lets see if we cant figure this out..

that said .. many of us... with too many years of experience.. might just throw the darn thing out.. and learn how to propagate one of your healthy ones... before this one infects the rest ...

sometimes... especially in hindsight... it isnt worth the time, effort and cost... to fiddle with a sickly plant... EXCEPT ... except ... for the shear search for knowledge.. but by that time.. we would have isolated this one... say.. 3 acres away ... which i presume.. you dont have in SF ...

more info.. and isolate it ... and.. BTW... sometimes.. simply digging it up.. and moving it.. and stressing the beegeebees out of it.. will force a survival reaction to live [some have suggested its a hormonal release].. and it will perk up ... [or better yet.. die.. lol.. there.. all problems solved .. lol ..]

more fact please.. a pic of the whole ... and...

good luck

ken

Rhizo is certainly better at the diseases and bugs than I am :), but this is the page I used for comparison...

Here is a link that might be useful: Cephaleuros virescens but on carambola

My apologies for not giving more info about this plant. I've discussed this plant in other forums and forgot I haven't given the specifics here.

The plant in question is potted in a 2 gal plastic pot and sits indoors year round. It is positioned near a south-facing window and gets a reasonable amount of filtered (blinds) sun although SF is notoriously un-sunny. Indoor temps range from 60-80F with around 50-80% humidity.

Originally the plant was in a commercial orchid mix. I initially noticed that each time the plant was potted up or fertilized, the leaves dropped. So I repotted using a depleted orchid mix to dissolve/remove extra solutes. By 'depleted' I mean that I soaked/rinsed the mix in warm water until the flow through ran clear. I now use a 3:1 of this depleted mix and perlite and the plant does much better and does not shock when I pot up. I am thinking about using an adapted 5:1:1 in the future.

As for watering, I give it a good flush with each watering (about once/week) to avoid accumulating solutes from the tap water. I have to keep the soil relatively wet or the plant will drop its leaves.

I have two other healthy plants that grow along side the sickly one which is why I was assuming it was not an infectious disease. No visible scale or insects present. Some of the photos for Cephaleuros virescens do look similar to the spots I see on my plant (lichen formation by fungal colonization of the Cephaleuros algae) although rhizo's description of the edema sounds promising to me considering the coloring and texture of the spots. I may try for some better photos when the leaf declines further. Maybe I'll try to get a look under a microscope.

Sounds like for now I'll separate if from the healthier plants just for precaution and read more about the causes you guys suggested... Any additional thoughts/treatments?

Edema seems to me to be the likely reason for the crusty spots. Looks quite different to me than the algal leaf spot images.

After researching the plant, I see that is a "Spanish lime."
So why, in San Fransisco, do you have it indoors? It should do well in a sunny protected site outdoors.

Is it San Fran? And more like 8b or 9a depending on which side of the bay...

SF 10 sign in, I was guessing South Florida where the leaf spot diseases are more common. And where the plants should still be outside...

SF = San Francisco
USDA zone 10a/b, Sunset 17

Indoors because I live in an apt and don't have the luxury of outdoor space in the city.

Looking at photos of edema, I'm definitely leaning that direction. It would also fit with my observation that the plant is very sensitive to water/salt levels and that my adjacent plants are unaffected. I have been trying to determine the texture of the algal spots. I would guess they can be scraped off. These spots are not removable w/o tearing the leaf. Also the coloration is tan whereas the algae seem to be more colored.

Don't worry about scraping anything off.....you'll only cause injury to the plant. Unfortunately, the indoor environment will never make your plant happy.

Duplicate post removed

This post was edited by rhizo_1 on Wed, Oct 9, 13 at 22:00

I do what I can while I can. For now I'm just saving up for a yard.

I understand....just know that edema is often a result of environmental conditions. In this instance, it might be as simple as the wrong plant in the right place. A more suitable tropical plant (houseplant) might thrive in your apartment.

Matching the right plant with actual conditions at the site is important for for indoor AND outdoor plants. "Right Plant, Right Place " is something of a mantra with horticultural professionals.

edema is a fancy word for a rash ...

if you had one.. the doctor would tell you to quit scratching it...

so rhiz is telling you.. wait for it.. dont scratch it ...

repot your plant in fresh potting media ... get rid of the old accumulations ...

THEN worry about rebuilding a toxic situation ....

especially if it has been in the same pot for 3 years ...

it might also be time to up-pot ...

if .. after three years.. this is the first sign of such ... the actual water itself.. cant be all that bad ... its your media ... IMHO

isolation was a thought .. obviously.. a media/water issue is not contagious ...

houseplants are very forgiving ... and garden plants are harder indoors ... but trees are very hard.. long term indoors ... revel i succeeding for 3 years ...

ken

But alas, I have little interest in typical house plants. I am only into tropical/semi-tropical fruit and nut trees. I have about 20 different species all grown from seed in pots around my apt. The fun is in the challenge for me. Even the sick plants I must keep for certain species b/c I may only have a couple specimens. If I have sufficient plants I experiment with different media/fert/growth conditions. All would prefer to be outdoors and in the ground. Almost all would prefer warmer more humid weather. The sick plant in question has been potted up 4 times in 3 years (I underestimated its growth rate as a seedling, the other healthy specimens are half the size) plus an additional re-pot where all the soil was removed with a little root maintenance (about 1.5 year ago). The re-pot was when I swapped out the medium for the depleted stuff. One pot up since then and it is doing much better, but I still haven't resolved the problem. Maybe it is time for another re-pot. I am thinking about switching up the medium again, something with a fairly high water retention and no perched water. I'm also interested to see if the plant would do better with dechloraminated water. The fact that the plant gets absolutely no added salts right now other than tap water solutes is making me wonder about chlorosis of some sort, but I am hesitant to give it any liquid fertilization. That would just increase the water uptake by the roots anyway and cause further edema it that is the problem. Maybe I'll try something foliar or some fish meal or something... Thoughts?

All containers have a perched water table. No way of stopping it. And if you put coarse stuff in the bottom of the container, the perched water table is higher than before.

Stop repotting. The poor thing needs to have time to put out some healthy roots.

I suspect you are killing it with kindness-- excess kindness. Citrus just aren't all that fussy that they need extremely low doses of fertilizer and/or distilled water.

Suggest you browse the Citrus Forum for advice of growing indoors. http://forums.gardenweb.com/forums/citrus/

Oh yes, and link to this thread.

Here is a link that might be useful: Citrus Forum

The plant in question is not a citrus. 'Spanish lime' is just one of its many common names; it is in the Sapindaceae family--more closely related to a lychee.

I understand the dynamics governing the PWT. Appropriate particle size and a good wick do effectively eliminate it. I'm not too worried about the potting up frequency. As I mentioned before, most of that was early on (2.5 years ago) due to the seedling growing at a faster rate than I had anticipated. It is a fairly benign process moving from the germination container to a small pot, then to medium, then to large. The point I was making was that if edema is the issue, I'll have to find the proper balance between maintaining high soil moisture/low osmolarity and increasing the transpiration rate in my limited setting.

I really appreciate all of your feedback. Thanks!

This post was edited by sf_rhino on Fri, Oct 11, 13 at 13:38