Sounds normal to me.. If its still green and growing i wouldn't worry.. The first leaves(cotyledon) always fall off when the plant matures.. Pictures are worth a thousand words.

Joe

Sorry, I wasn't clear. I don't mean the cotyledons, which fell off awhile back, but the true leaves. I'll try to snap a picture when I can (not till tomorrow).

Posting a picture would be a big help. If not possible then you need to provide far more details. Otherwise it is just guess work.

leaves curl in slightly at the edges and become a little brittle,

Can be excess salt build-up in the soil from over-fertilization. You don't mention what potting mix you are using or what and how often you have fertilized or even if the plant is in the ground or in a container. All important info to have.

Whenever a fourth leaf begins sprouting, the lowest/oldest leaf falls off, just like that, so it never gets more than three.

Indicates the root development can't support additional top growth. Can be caused by something as simple as over-watering and root rot or by being root bound in the containers, or by over-fertilization, too cool soil or air temps, or several other possibilities.

Really need more information to narrow it down.

Dave

This post was edited by digdirt on Tue, Apr 16, 13 at 19:22

Sound like a simple under/overwatering.. Ten to one it is overwatering.. The soil should be moist like a rung out sponge.. Water thoroughly, let soil dry, water thoroughly, let dry..

Thanks, guys. Sorry I couldn't grab a picture. I figured out what it was (I think) and made an attempt to fix it before taking a pic. I was gone overnight, and when I came back, there was a white-ish film on top of the soil. At first I thought it was mold, but it was more mineral than fuzz, so I think Dave's right about the fertilizer salts. My solution: scrape off the top layer of soil and run some water through the soil to drain off any remaining salts. Figured it was definitely a fertilizer issue since, awhile back when I noticed the leaves curling, I had fertilized it some more to give it a boost (haha, joke's on me). What do y'all think?

Whitish film sounds exactly like damping off caused by overwatering.. If you only fertilized a few times and it really did leave a salt crust, that's one strong fertilizer! What kind of fertilizer were you using? What concentration? How frequent? What kind of water you using? What potting soil? Is your other plants the same way?

If it is the fertilize flushing the buckets with water will help.. If it's dampening off(overwatering), you are making your problem much worse!

Best of luck,
Joe

This post was edited by Raw_Nature on Fri, Apr 19, 13 at 22:51

I haven't had any other problems with damping off--the area is well-ventilated. I think there was a problem because I was bottom-watering and thus the salts couldn't drain out. It's not a strong fertilizer by any means.

If you were bottom watering, how would there be a salt accumulation ontop the soil? How would there be a salt buildup in the first plant place, if you use a weak fertilizer as you mentioned? Even very strong fertilizers at the proper concentrate doesn't burn plants, nor have salt buildup after a few feeding,let alone scrapping salt off the top of the soil! Something doesn't add up..

Again- What kind of fertilizer? What concentrate? What potting mix? What water? Do you care for your other plants the same? Are they doing ok?

This post was edited by Raw_Nature on Fri, Apr 19, 13 at 23:57