The happiest thing is you have a Meyer lemon; the difficult thing is the Meyer is quite sensitive to light changes. If you have moved it from outside to inside, it will likely drop most, or all of its leaves, to be replaced by new leaves better suited to the new light conditions.

When you put it back outside in the Spring, put it first into full shade; after two weeks to partial sun; and another two weeks to full sun. Reverse the procedure in the Fall and you will avoid the all to common leaf drop.

Of course. I did the gradual thing last June, did NOT reverse it bringing it in.

Sunny, it all depends on how you have been caring for it.

I find that yellowing on my Meyer trees for years as always been the cause of varying issues. Either it's from over watering, poor root development, using water with a high pH, a compacted mix, lack of proper light, temps being too cold or too hot, a lack of nutrients and so on.

Earlier in the season when we had sunny warm days, I would of been concerned about the mix and or fertilizer if it was yellowing all summer. That has passed.

Now, in your case I would be concerned with the cold temps not allowing nutrient absorption, causing nitrogen deficiency and yellowing of leaves all at once, which is probably a problem you had to begin with for some reason.

If your temps have been cold lately, seeing you live in zone 5, I might suspect root rot that pre existed then was exacerbated as temps have cooled off quite rapidly. If your mix is moist with those cold temps, I suspect further rot.

I don't worry about graduating my trees at this time of the year light wise, since the amount of sun we get now is minimal compared to southern folks and late summer, but I do worry about how long it takes for the mix to dry out once inside.

Make sure your mix is drying out appropriately, and if not, change it asap.
Also make sure that you are giving your tree a very bright area in your home with fresh air if you can.

I would not feed it at this time until you check the roots and make sure they are healthy.

What kind of water do you use? Tap, rain, well or some other? Have you ever used vinegar if your tap has a high pH?

Mike

Thanks, Mike! I believe that wet roots may be the problem. Because even though the mix I made up after checking here, when I bought it, had lots of vermiculite and drained quickly, and it did so great in the house until late April, and outside until about a month ago - it has been very very wet here!The fact that we have had lots and lots of wet weather and the pot saucer was overflowing when I brought it in is definitely points to wet roots. I am afraid of trying to repot it with that gorgeous almost ripe lemon on it though! I am assuming that it won't continue to ripen if it is off the tree. What to do, what to do....It is in a sunny indoor spot, assuming we get any sun that is.

Put a wick at the bottom of it and encourage the mix to dry quicker.

Also, you may have to choose loosing a lemon or the entire tree. What to do is right. If you tranpslant correctly though into a much more porous mix, it should hold on fine like mine do.
Vermiculite does have a tendency to break down very rapidly leaving the mix to hold water much to long for citrus.

Good luck and please let us know what you decide to do.

Mike

There might be a problem with your plant. It might be suffering from pests or sickness. try to check it out before it dies.

Would a product called perlite be better than vermiculite? Doing the repot thing this pm and perlite is available at local Agway.
Also - no evidence of any pests or disease. The leaves are perfect - except for being yellow.

Yes! Perlite is much, much better for container Citrus mix! :-)

Hello, Mike!

Josh

Hey Josh! good to see you:-)

Yes perlite works wonders as Josh says, and in fact I have a big bag of this stuff.

Mike