Yellow vein chlorosis:

http://edis.ifas.ufl.edu/ch142

http://fshs.org/proceedings-o/1960-vol-73/69-79%20(LEONARD)1.pdf

Thank you for the links. I already have the first link bookmarked as a reference guide when I first got the tree. I skimmed the PDF and it is a case study on what causes yellow vein chlorosis when not caused by disease or bark/root injury and they concluded that it is a cause of nitrogen deficiency linked to calcium during an abnormal period of cold weather in Florida.

I came to GardenWeb for advice bc I can't pinpoint whether the problem is related to nutrient deficiency, root injury, or root disease which the PDF manages to rule out 2 of the 3 using leaf analysis and testing of the fungus/pathogens. Something I'm not really capable of doing without a lab team with me.

I'd really like to get some advice on how to figure out more specifically what my tree is trying to tell me.

Also the first link has a lot of great information but none of the examples and descriptions they give for the different nutrient deficiencies show the specific pattern my leaf is exhibiting :(

the middle photo looks ok to me, pretty healthy looking plant. May be put it in the ground soon and let it grow.

Thank you so much Meo! I don't know what is average or above/below average when it comes to lemon tree health so your comment just made my day! And also relieved a bit of my worry for my lemon. I'm going to continue my routinely care for now and cross my fingers that it's naturally shedding them.

I may live in zone 7b but it definitely gets too humid during the winter in my neighborhood to risk putting it in ground. Microclimates make things so complicated :( I will watch and see how my Meyer reacts to the winters here for a couple years before deciding to put it in the ground or not. At least in the container, I can take my lemon with me if I ever move to a new place :)

Again, thank you so much Meo for sharing your opinion with me. Any little input from more experienced gardeners is valuable in my eyes.

Did you find the GW post "meyer lemon citrus yellow veins" by kazarko in 2015? Might be a similar problem. I think the conclusion there was nitrogen deficiency from overwatering (so the roots couldn't take up nitrogen) Good luck!

In zone 7B I wouldn't put the plant in the ground either, not unless your going to do a whole protection thing...and it doesn't sound like that's your thing. Plant looks pretty good to me. If the new leaves are fine then that's all that matters, because thats the indication of what is not what was. Get yourself a little insecticidal soap/alcohol in a cheap spray bottle and keep it on hand (sometimes I toss in a wee bit of fertilizer) for bug outbreaks. Plants will also drop older presumably shaded lower leaves (I believe life span is a year and a half or something)that are shaded and the nutrients are going to the new leaves. You may want to consider a repot in the infamous 5-1-1 mix as well. enjoy your lemon.

Citrus loves humidity. The leave with the yellow looks just like an old leave that is to fall off soon. If lots of the leaves look like that then I would worry that something on the roots is not right. How long do you have this citrus?

I agree with Susanne. Your tree looks perfectly healthy. Those leaves that are falling off are just old and the tree is shedding them as it grows new ones. My trees do that all the time. I would leave it in a pot if I were you. I live in 7b and do not think citrus would survive in ground here, but it may be different for your area.

Thank you you guys so much for your input! It really means a lot to me to see people helping out since I don't know anyone else that has any serious interest in growing fruit trees.

I did suspect the shading as the culprit of those yellow markings bklyn citrus. But knowing what my tree had experienced, I couldn't be entirely sure of it so I'm glad I mustered up the courage to come ask.

I agree with you on that Laura. I'm heavily leaning towards eternal containment for this tree until the day I don't need to wear puffer jackets during the winter.

Laura LaRosa, I've had the tree almost exactly one month now. One day I hope to have a trunk as thick as the ones I saw on the trunk comparison thread!

Give it time....it will get there! If it were not pouring right now, I'd post a photo of my meyer with his trunk. They are loving the rain though...

My Eureka is doing similar: several bottom leaves with yellowing veins fell, but the top of the tree still has the new flush it arrived with a month ago.

Right after I got it, the newest shoots started turning brown and dying back. I've since corrected the problem (I hope), but there has been no new growth and the flush leaves have not yet matured. No other visible ailments either, though. I guess no news is good news, for now.

-Kelley 8a

What did you try that helped you correct the problem? The yellowing of the lower leaves on my tree started to slow down. I don't see them yellowing as quickly but there are still a few developing those yellow veins. However I looked over the tree for long time today and noticed it's been pushing out new branches from the upper nodes along most of my long branches. So it must have been trying to find an equilibrium in the foliage. And of course, being greedy in wanting to grow so much..the upper flush of growth that has been light green has started to show splotches barely fading to yellow mottling. So I agree with nikthegreek that the tree is trying to push its limits with the nutrient uptake. Mine was due for a feeding anyway so it was right on schedule. Other than that, your tree looks amazing! Lovely dark green with only a bit of light green at the very top. It looks all perky and happy

I believe I only corrected the problem of the dying branches (I hope - no new turning brown). Tonight, I noticed several more fallen leaves, but only from the bottom - starting to freak out a little lol. A month ago, I thought it was suffering from a little root rot (brown shoots) so I washed the roots and repotted it in a mix of perlite, vermiculite and a little sand (all I had available at the time). I think the sand may be holding too much water. It is on the same watering/feeding/light schedule as my Key lime. My key lime looked rough as well for awhile, but is now full of blooms and a few tiny fruitlets (all in the past few days).

No new growth on the eureka :/. Glad your tree is doing much better!

Thanks Kelley! I'm still on the fence about how well my tree is doing but so far it doesn't look like there's any large infestations or obvious diseases. The only explanations would have to be root rot, lots of fungus gnat larvae, or not enough food for the tree. And I'm hoping it's not the root rot!

With your mix, it might be due to the fact that each of those materials hold water very well. From all the research I've looked at online, vermiculite and perlite are usually recommended to be chosen for just one or the other in most soil mixes. Or a mix of both to equal 1 part. The only time I've seen a mix include both as separate parts was IVOrganics on YouTube but I didn't stay updated on how the tree fared. If your vermiculite was a larger, coarser type then it might be ok? I've read vermiculite tends to hold water very well due to absorption while perlite just gets wet on its surface. Is your lime also on that same mix? It probably is just the mix's drainage...I think an expert should give you a more informed opinion on your eureka. I've had my first lemon for only a month now. My advice would probably be to not listen to my advice lol