My lime tree (about three years old) has developed yellow tips on it's leaves. Other than that it seems to be doing great. can anyone enlighten me as to what's going on with it? I've also got young lemons and oranges that are doing fine.

Hard to say without a photo, but you might check photos of salt burn or biuret injury as possibilities.

Thanks Malcom, I've uploaded two images to ImageShack but I don't know how to get them to show here.

Malcom, I think I've got the images, can you tell me what it looks like? New growth on the tree looks great.

Hard to say for sure, but it does look like biuret. Does the fertilizer you're using contain a significant amount of urea? If that's the case, it likely won't affect productivity of the tree or rate of growth, but if you just don't like the look, you could go with a different fertilizer source.

Malcom, I have no idea what a "significant" amount of urea is. On the fertilizer package it lists 3.7% Urea Nitrogen. Is that significant? If so what should I be looking for in a new fertilizer? Thanks for your your time and expertise, I really appreciate it.

Yes, 3.7% is significant. Not a bad thing if it's highly purified urea (to remove the biuret). Your tree looks otherwise healthy, so I'd not worry too much about it. But you might try a zero-urea material and see if the next flush lacks the yellow tips, to see if that's the cause, if it bothers you.

Thanks Malcolm, I love my little trees and don't want to let anything get out of hand if I can help it. I'll start looking for a new fertilizer.

Malcolm
I would like to ask a question:
Summer I have a big biuret toxicity in my citrus. I have red, that, the biuret is not a problem if it used on the ground.
""""Urea used for spraying should have a low biuret content (less than 0.4%), as higher levels cause leaf burn. Biuret is not a problem when urea is applied to the ground.""""
I used 97% urea for irrigation, to reach 250ppm Nitrogen.
What is the truth?
Thanks

Oli, I suppose that depends on how you define a "problem." It's true that soil-applied urea normally does not reduce productivity or quality of fruit, but it certainly can cause leaf symptoms. But your photos don't look typical of biuret toxicity. What variety is this? If it's one of the dark red grapefruit (especially Star Ruby), it may just be a natural genetic proclivity to make leaves like that.
Malcolm

Thanks Malcolm.
You right it is a red grapefruit. (especially Ruby Red).
Star Ruby has the same symptom see next picture.

I have white type grapefruit, but the same symptom see next picture.

When this symptom started on the grapefruit (at the same time), I have some sign on the other citrus see on the Tahiti lime.



Oli

Symptoms on the lime are typical biuret toxicity. But the grapefruit leaves are not at all typical. However, I've never seen leaves like that on a white grapefruit. You aren't using any systemic herbicides are you?

I never used any systemic herbicides.
I hope, that the 2013 year will be better than the 2012.
I decided, that I will use Universol Green (23+6+10+2MgO) for fertilizing.