orange tree looking very pale in Portugal

Maybe the wrong place for this question? I live in Portugal and planted an orange tree on my terrace in a very large pot about 1 meter heigh and 1 meter diameter in earth that i bought at a garden centre. I was advised by more than 1 person that this was possible and I have a few trees (apple, avocado, Japanese cherry) growing very happily like this. I have a large concrete terrace that I'm turning into a garden by building pots and heightening patches for fruit and veg. Everything is growing great and doing well. the orange tree is the only one that looks very pale, actually everyday its getting paler.
Some people are advising me that it's getting to much water, others say that it's getting to little! At the moment it's raining a lot but my neighbours orange trees look fine. Is the earth type wrong and should I be digging up some of my neighbours ground or should I be fertilizing the tree with something?
It's a young tree about 1 meter high?
Thanks for any advice!

I can´t exactly answer your problem, but I have had problems before with citrus trees dying in a very similar way, when in pots, and enduring the winter. Apparently they are sensitive to the lack of sunshine and excessive cool and wet weather. They are trees native to frost free warm climates.

In the ground, the tree establishes itself and has a better change to thrive but in pots in does suffer much more.

The ones I had before in pots died, even when I brought it indoors to a greenhouse, it did not matter what I did to make it happy.

Perhaps it need its roots to spread in a way that containers normally do not allow, either horizontally (like an avocado) or vertically (like a pawpaw). If the tree senses that this is not so, then it might receive signals of excessive moisture or lack of moisture and go into shock. Sincerely I dont understand this problem.

By the way I had similar problems with other trees in containers before. My moringa tree also seems to be found of, once in a while, so through a period of sheding all of its leaves down, then it recovers, but I am sure that this points to the lack of summertime warmth; somehow the plant figures out that it is inside a greenhouse and its winter (even with lights). I also notice it needs excellent draining and just a constant low level of moisture (and space for its taproot). The avocado is another tree that tends to behave in a similar way, but it needs excellent draining, rich soil and a wide container (to simulate its nature conditions; it spreads roots horizontally under the canopy of a subtropical forest)

I guess if we dont simulate the tree natural conditions, then they suffer. Citrus like also to grow under the shade of warm semi-dry subtropical forests.

Could be iron deficiency, my container citrus seem to get iron deficiencies quite readily. Take a picture and I can tell you, early stages of iron def in citrus generally manifests as a generally pale green color, adding iron generally turns it a very deep forest green. An analogy I tell people though is that a plant in a pot is like a bird in a cage; wild birds don't need cuttlebones or toys. One has to manually add most/all nutrition and there is no subsoil to mine trace minerals from. Also, don't let anyone discourage you from growing citrus in your climate/in a container; I grow satsumas outside in containers in an area that gets approximately zero degrees F, or -18 C, in a bad winter, and I don't bring them in either.

if you're able to grow avocado then you should be able to grow most citrus varieties, some are much more cold-tolerant than others, like satsuma mandarin/tangerine, meyer lemon, and loquat (sort of a citrus). it is normal for some citrus to lose some leaves over the winter (up to a third) with no real harm to the trees. but leaves do not change color in response to cold.
i second that it must be some sort of deficiency, and very slow and careful fertilizing is probably necessary. just do it slowly, and don't expect a miracle overnight
hope that helps!
-Tentance

http://oldescrubland.blogspot.com

Ok thanks. Im going to try adding iron and or citrus fertilization. Or is that the same thing!

nope. a citrus fertilizer will just be a regular fertilizer with a fancy name like, for citrus, it will be a plain balanced fertilizer. an iron amendment will be labeled as such. university of florida IFAS website has a ton of information about citrus deficiencies, some with pictures. We've spent a lot of money learning about citrus here in florida. i would check it out, if only for the pictures and the recommendations!

Thanks Chrissy, I'll check it out!

I checked the website and it does look very much like my tree is suffering form iron deficiency! So I'll try that first.