First, citrus trees have surface roots, so they do not have to watered deeply. Their roots are out at the drip line, the area where the outermost leaves are. So you may want to adjust your watering. Second, yellowing leaves are usually a sign of iron deficiency which citrus tend to have. You can add iron (Ironite) as a granule or foliar spray. Third, you want to fertilize your citrus three times every other month (if you're using chemical fertilizer) starting around Feb/March depending on where in SD you are. I prefer an organic fertilizer which can be used at any time. I would stay away from Miracle Grow especially. Fourth, last year was a strange weather year. My mandarin and navel trees were particularly off. So, it may just have been the weather that caused your lack of fruit. Lastly, you can prune the trees however and whenever you want. Some people say that fruit trees should only be as tall as your arms can reach. Hope this helps and good luck!

Thanks for your answer! Ugli (or tangelo) is getting close, especially by look, my fruit ins question's skin is thicker and even more gnarled though. The flesh is clearly lemon flavored(a milder watered down version), without tangerine or pomelo flavors, and deffinitely not sweet....Just got done picking- that one little tree gave over 200 lbs. this year.I do have pictures, just didn't know how to post...I can email- TX!

Its difficult to tell what it is from the photo, have you got one of the leaf from the top?, from a photo of the whole leaf you can narrow it down a bit, but it is difficult to be exact, it depends on the size and shape of the leaf, and the petiole size/shape in relation to the leaf For it to flower depends totaly on what it is and wether its been pruned at all, from when it was planted it keeps count of how many leaves it has grown, and when it gets to the right amount it will start to flower and produce fruit, if you trim bits off the top the leaf count is reduced, so it needs to grow more to age enough to mature, so with all citrus grown from seed its always best not to prune at all lemon and lime can be fairly quick, sometimes 3 years usualy more like 5 years to flower and fruit, grapefruits can be far slower , more like 15 years Has it ever flowered? What plant food do you use?, If its not fertilised and watered correctly it will slow down the growth and can prevent it flowering due to lack of the correct nutrients, too wet can prevent it flowering as well, you are best using a citrus feed in the water when the plant is dry a few inches down, then soaking the plant, they like to be dry then soaked then dry again

I took the leap of faith today and pulled it out of the container. It looks like it was very root bound and therefore nutrient uptake was limited. I had no choice but to gently loosen up the roots and re-pot in a 2 gallon. I am in Canada in the middle of winter but I think my plant thinks it is spring based on the artificial light and flowering. Hopefully it doesn't stress it out and cause flower/leaf drop. I trimmed off maybe 10 leaves off. Do you guys think its a good idea to take more off? I will just water with the water + vinegar for the next month or so. Then I will switch to Miracle-Gro All Purpose 24-8-16 + vinegar which is closer to what you guys recommend. Thanks all!