Indoor Gardening and Houseplants: Ponytail has thin light stripes, 3 by David_Sweden

David_Sweden wrote:
Hi. In short: I am checking up on my Ponytail "palm" (Beaucarnea recurvata) which I got 1½ years ago, and one peculiarity which I can't find a good explanation for is the light, thin stripes you can see in pictures No. 1 and 2.

Longer version:

Background: I didn't worry too much about plant healt until 1 month ago (had a basic book, asked friends & stores, that's about it). I had some pest problems that ended 3 years ago and haven't bought any new plants since then. Until 1 month ago, when I also tried to read up on repotting and all other care issues, tired of having plants that slowly die one me, it would be nicer if they were healthy and got bigger, especially since I like palms and other exotic plants.

This Ponytail has received water in small bursts until 1 month ago (meaning only the top inch or so is likely to ever have been wet), when I decided to thoroughly moisten all plants' soils, and not water again until it is just slightly moist (more on the dry side for succulents like this), aided by a cheap moisture meter (and other methods, since the meter isn't completely reliable). It sits in a bookshelf, energized mainly by a 12W flourescent light bulb with reflector which used to be at ~1' distance but since 2 months at 1/3', giving up to 10 klx at the leaves; it also has a northern window 3' away. I know it prefers more sun, but I tried this with another Ponytail long ago without the lamp and it got the characteristic "hippie hairdo", but this one does not, it still has the perky look it always had. 1 month ago, I changed the top ~½-1" soil.

Health review: It looked to be in very good shape (to my defense it's been on a shelf so I couldn't look closely without standing on a stool), besides brown tips on some leaves but not so bad. But when I looked closely I found a few symptoms I tried to understand:

• The thin, light stripes, beige color, looks like it is dried out in that small stripe, it is visible on both sides, about 20 leaves have them, some have two, length between 1/5" and 1", not on the newest leaves. No indications on insects or pests or anything, no hole thru
• Several leaves (a dozen) are "bent" more than what I've normally seen in pictures, but I did find the picture below from Wikimedia/"Botanical Garden Karlsruhe, Germany" with similar bends. I can imagine that the fact the leaves cross-sectional area is U shaped makes it more prone to being bent and the fact that the older leaves are a bit thicker. But many of the "light stripes" coincide with these bends, I guess both indicate some mechanical weakness and maybe one can cause the other. I haven't thought much about this before, but I took a picture after I changed the top layer of soil and as you can see some were bent then too (maybe fewer) see 3rd image.
• All new leaves are brighter green, and so are the beginnings of all leaves, and most new leaves are quite narrow, but I checked in a shop today and apparently this is normal (even though mine might have a bit more of this, but it's no big difference).
• I'm not sure I want to continue watering until it's thoroughly wet. I did it 3 weeks ago and was happy to see that after a few days (almost a week) it was almost dry again. But I watered it again like this 3 days ago and it's still quite wet. I read that the most important roots are on the sides and shallow anyway, and that it can easily produce new roots if damaged. I'm worried about root rot. There are no yellow leaves but I investigated the soil and roots 1" deep, of the 3 roots I found with diameter ~1/30" 2 were white (or light beige) and one was white after i scraped it with my nail; there also were much thinner roots which were darker. I read a sign of root rot is if the soil smells like mold, fungus or wet sock, if I stick my nose in it it smells very slightly like mushroom which I guess could be a bad sign?
• It has a bunch of small, gray spots on some (older) leaves, only at the inch closest to the meristem, only on the top side, and it can't be wiped off of scratched with my nail. See last image.

My plan for now is to first put it in better light until the soil is dry (not moist), then flush it with pure water to remove excess salts, and after that water it with ½ dose of fertilizer. And as soon as it isn't wet anymore, I will move it back to where I want it to be, and after that I plan to water it only from the top so that the top ~1" gets wet (to get all the soil wet I have to let it sit in water plus water it from above about 10 times, due to the nice looking but annoying bonzai-like pot). I think the idea to thoroughly moist soil for all plants sounds good but the exception to the rule might be a Ponytail in bonzai pot with low light situation.

Regarding the thin light stripes I'm thinking it can't be bugs or pests, underfertilization not probable since it need almost no fertilizer from what I heard, I'm thinking of things like too much water (even root rot), too little water (not lately though), too much fertilizer (will flush soon), or possibly that stabbing the soil with the moisture meter probe might kill off roots (seems less likely since it's pointy and I read it creates new roots easily). Low light I haven't heard can cause anything like this? Perhaps the bends are for the same reason? And I hope there is no reason to think there might be root rot (the smell being the only, weak indication I can find so far).

http://upload.wikimedia.org/wikipedia/commons/2/2b/Beaucarne...

All input is welcome. Right now it looks ok but I fear it might get worse if I don't understand it. Thanks in advance.