Your tree is underfed or it can’t absorb the nutrients. I think the fertilizer you are using would be more appropriate for an in-ground tree. Most of us here who grow citrus in containers use either Foliage Pro, Peters, and Oscomote plus - or a combination of the three. It could also be that the soil mix is not appropriate for container growing. What mix do you use? If you give us more information, we can help you more effectively.

Thank you Laura for the reply.

The soil mix I am using is 1/3 peat moss, 1/3 potting soil, and 1/3 perlite.

Thank you so much Laura. You have been extremely helpful. I will keep you updated on my progress. Cheers!

Another thing to consider... If it's been in the same pot for those 3 years it may be potbound and having issues with root congestion or root rot. The pot looks good sized but you never know what's going on down there until you slide it out of the pot and have a look.

Thank you James, it hasn't been that long yet, but I will check out the roots when I replace the soil with the 5-1-1 mix.

Cute tree, even with the yellowing leaves!

I am currently growing some from seed but know I should really buy one from a reputable nursery instead. Maybe soon ☺

A side note about Pro Mix, it's mostly Peat and Perlite with some fungicides (I ❤ Pro Mix) So maybe if you make you mix with just those for now it would help? The fungicides are great but these are not cuttings or seedlings so you might be okay.

Brandon, I use Pro mix too when not using the 5.1.1. and I like it a lot. It is not as fast draining as the 5.1.1 mix that I use, but it does a great job. So, as long as you are using a very good porous mix with the right pH solution and the right nutrients, it will do very well. How is it doing now? How did you do? Would love to see how things are going for you)

Have you seen Brian's trees yet? He is also a Canadian)

Give it that he keeps them in a greenhouse, but many can keeps their healthy inside the home as Laura has proved. Mine do well too.

Mike