Lots of trees have small/sparse roots and if nature hasn't seen fit to trim them in the wild to accommodate that, I don't think you need to worry much. But I might consider a shorter, wider container if you're worried. They look happy enough and I don't believe in messing with success :-).

Damp-off of very young seedlings has never been that much of a problem for me, but I think the reason for that may be how I germinate them to begin with. It's a cue I took from my mother, which is basically to put the seeds in the same pot (around the edges of the pot) with an adult plant then water the adult plant the way I normally would. It means I don't use bottom heat and whatnot, so things sprout when it naturally becomes warm enough for them, but pretty much I don't worry as much about damp-off because there are older roots using the same water in the same pot. It's when I take the babies out that I experience problems. As I mentioned, I actually put some young Calamondins back with their Rangpur Lime host plant to recover after this winter. The other thing I practice quite a lot is the theory that it's not dead until it's dead and even if I'm sure its dead, it's worth a shot. You wouldn't believe the number of citrus seedlings and cutting grown figs I had come back to life after the moving issue the spring before last. I actually use the much maligned self watering pots, but not as self watering pots. The designers would say I'm using them totally backwards. I'll go down my line of trees and tip them to dump the water if I notice water actually standing in any of the reservoirs. (I can't imagine using them to "self water" because what that really does is create a high water table for root rot.) If you've ever taken a moment to look at one of those things empty, the bottom of the pot that sits inside the reservoir is like a pasta strainer. So long as the reservoir is always empty, drainage isn't a problem.

Hmm. I just responded to another poster who has a citrus that also is failing to thrive. He posted that quite a lot of pine mulch, complete with wood chips, was mixed into the soil. I suggested that might be causing a nitrogen deficiency. Anyway, I can see in your pictures that the tree is heavily mulched with wood chips. Normally, if wood chips are on top of the ground they should not cause a problem . . . but I can see an awful lot of them in those pictures, and your tree is quite petite! Another possibility is that in applying the mulch you have smothered the tree's feeder roots. Someone with more familiarity with the cultural practices in your area should be able to help, but I would say that for such a small tree the mulch is probably not helping. In fact, it is probably hurting. For that matter, your problem may well be a combination of both possibilities! Think of it this way: a mulch ring three feet wide and two or three inches deep is usually fine for a tree that is ten feet tall and about the same diameter, but you have a tree that is about a foot high and wide and a mulch diameter of what looks like at least two feet. Thus, for its size, your tree has a shallower and smaller network of surface feeder roots than the larger tree, but is located in a mulched area that is, relatively speaking, the equivalent of a thirty or forty foot wide mulch zone around the larger tree, with probably a similarly wacky depth to that mulch! All of which is to say, I'd remove the mulch!

I would tend to agree. I would re-pot to a signficantly larger pot, as you've got quite the canopy going. Use a better draining potting mix. There are a couple of great recipes on our forum that our container citrus folks use with good success. Search for either Gritty Mix of 511 Mix. And, 20-20-20 is pretty potent for container citrus. Better to use that with in-ground citrus. I would be inclined to use what most of the container citrus folks use, which is Foliage Pro's Dyna Gro liquid fertilizer. Better and more appropriate NPK ratio, plus it provides all the micros as well. Some folks will also supplement with a time release granular fertilizer with similar NPK ratios and micos as well. Patty S.