Additional picture

Check the temperature of the soil in the pot. I had the same problem the you are having and after eliminating everything else I could think of I checked the temperature of my soil. Even on a warm day the soil temp was 55f due to evaporation. I believe I was having WLD even though it was summer. I wrapped plastic wrap around the terracotta pot to eliminate the evaporation. I also bring it indoors at night since here in Oregon nights are always in the 50's. My tree hasn't had any new growth yet but it did stop dropping its leaves. Unfortunately my poor Meyer lemon looks horrible right now. Good luck with your tree, Jack.

I don't believe it's an issue with temperature as the weather here in the northeast is quite warm. I do check the moisture level daily using chopsticks and I water as necessary. Thanks Jack

It's not the air temperature; it is the soil temperature; and if that is a terra cotta pot in your climate, evaporation from the pot will cool the soil; and citrus roots do not like to grow into cool soil. You can simply paint the outside of the pot with a good quality oil base paint; and it will eliminate most of the evaporation, as well as making it prettier.
If that is a plastic pot, then evaporation is not the problem and you may just be experiencing transplant shock.

I don't know how cool your nights are but for me (Western Oregon) nights were so cool that it would take forever to warm up the soil. We are having 80f days and the soil in the pot was in the 50's. If I was you I would use a meat thermometer and see what temp the soil is, if the soil temp is cooler then the air temps that might be your answer.

I have been using terra cotta pots for years without issue. Of course, this new one for the transplant is bigger, but the soil is moist, per my chopstick check. I just assume that the tree needs more time to produce new foliage.

Moist soil and a moist pot equals great evaporation. I'm not saying this is your problem but it was mine. Next to my Meyer lemon I have a small key lime tree in a smaller terracotta pot. I treated them both the same but the smaller pot was always warmer then the larger terracotta pot and I didn't have any problems with leaf drop.

Do what you want; we are only giving you the advice of people who MIGHT know a little more than you. If you have been growing CITRUS in terra cotta for years successfully, keep doing it; but you will not continue to be successful.
In warmer climates terra cotta can actually be an advantage; in cooler climates it is almost always a detriment.

I live in Stockholm, days were 55f and nights were around 50f because of cloudy and rainy weather for few weeks. But today it was extremely sunny and i checked the temperature in the soil of my citrus's plastic 10" container and it was 91f and outside it was 77f and again night is going to be 50 ;( is this type of temperature change disturbes plant ?

Maybe there is some confusion as to where I live. Southern NJ. Warm summers and the citrus spends the winters in my heated greenhouse.

Is there a reason not to check the temperature of your soil?

This is July the hottest time of the year, especially south of me. I have this problem in clay pots when the cooler months are here but not hit July.

When transferring to the gritty mix, it take time for trees to respond to it and especially if you are not fertilizing almost right away, heavily.

I would be patient and fertilize heavily. I would also make sure to keep it on the moist side.
Once the cooler weather starts to appear, about the middle of August, I would wrap that pot in bubble wrap or plastic as suggested or transplant into a plastic pot as soon as you can

Mike

I'm surprised no one has mentioned this....

High Summer is a really rough time to be bare-rooting and re-potting most plants, let alone a finicky Citrus. In fact, I'd be even *more* surprised if your tree *hadn't* lost any leaves.

For now, as Meyer Mike said, keep the mix moist. If there were roots in the upper inches, they're most likely dried and dead by now.

Also, how long did you keep the tree in the shade? I would have kept the tree in the shade for 1 - 2 weeks.

How are you fertilizing? Again, I agree with Mike - now is the time to be fertilizing good and heavy.

Josh

I repotted one month ago and have been using foliage pro. Thanks for your advice!!

Did you shade the tree after re-potting? If not, no surprise that it lost leaves.

Full strength...even double strength....Foliage Pro once a week should help the Meyer. I always feed my Meyer at a heavier concentration.

Josh

Josh we discussed my tree in another thread and I did everything right (except re potting in early june) but my soil temps were always cool in the terracotta pot. I believe thats why my tree dropped its leaves and is why I brought low temps in the soil as a potential cause in this thread. Unless the OP actually takes the soil temperature throughout the day there is no reason not to consider this as a possibility. Kiropod good luck with your tree.

I wouldn't know about cold soil temps....I guess I've always gotten lucky. I've re-potted at some inopportune times, but usually when the weather and the potting mix are both cold. Cold, inactive roots and sunbaked leaves, that's a bad combo, I'm sure.

Keeping the mix moist in the weeks following a re-pot is very important. That's something I had to learn when I re-potted my avocado and failed to water regularly enough.

Josh

Thanks everyone. I recall shading it only for one week post-transplant, which maybe part of the issue. I will continue to be vigilant with the foliage pro and insulate the terra cotta in the fall. While I have not seen new foliage development to date, I also have not seen any additional leaf loss.