The leaves look hungry. What are the indooe temps?

Probably in shock from the change in light.
I think grow lights need to be on for about twice as long as the optimal sunlight for the particular plant.That means your lemon is not getting enough light.
I would do research on growing citrus under grow lights during the winter. You want to be careful of over feeding too.

The yellowing veins in the leaves might be due a nutritional problem. Here's some info from the Univ. of FL:

https://edis.ifas.ufl.edu/publication/CH142

The indoor temp is usually around 21-23C so it shouldn’t be too cold for it.

Based on that article it seems like nitrogen deficiency due to decreased uptake from the cooler weather. What can I do about that??

Meyer lemons ar know to be difficult to grow.

Nutritional deficiencies are often due to problems with the roots because the roots cannot absorve the necessary nuitrients. See if you have root rot: pull the tree out of the pot and see if you have brown roots that easliy break apoart and / or there is a foul odor.

I alternate between the Miracle Gro Shake 'n Feed (10-5-15) and Miracle Gro all purpose plant food (24-8-16).

What should I do?

==>> how many times does a plant need fert.. in the few weeks since you bought it..

severe stress from moving from grower.. to seller to you..

probably overwatering.. trees simply dont need a lot of water.. especially in the house.. let the pot near dry between deep waterings...

never fert in fall or winter... im sure the new plant came with enough fert in the media.. to last up to a year... its is a tree.. not a child.. it does not need to be fed often.. nor clothed.. nor educated ...

leaves NEVEr look hungry.. i dont know what that means...

im not sure you can save this one.. unless you start watering properly.. and it somehow releafs in a few weeks or months ... its going to take a lot faith for you to just ignore it during this period...

if it doesnt releaf.. its dead.. or will be dead ...

try not to love your plants to death ...

welcome to the forums.. next time.. add the houseplant forum .. those are the peeps who grow tree indoors ... im pretty sure the orchard forum died..

ken

Thanks to all who have answered. I fed the plant with Jobes Organic

Fruit and Citrus food in the summer and it greened up well and flowered outside. It is now pretty cool here and I have moved the plant in, along with a lime tree about the same size that I purchased this summer. They are both droping leaves like crazy. Both have small fruit on them about the size of a little finger thumbnail. Those are dropped off as well. I think I am going to buy some lighting for them for the winter. These plant are in my living area in the dining room and I have no where else to put them. The only other place is the basement, and I don't think that will work. I would have to keep the lights on 24/7 and maybe the plants would not like some darkness in a day. I don't want one of those large floor model lights with all of the arms coming out of them here during the day. I may put it on at night and remove it during the day. Not a really good plan, but I don't know what else to do. If anyone can recommend which light to buy on amazon, I would appreciate it. I have looked briefly at them and they are all sorts of types of light spectrums for differing circumstances.

Organic fertilizers are the wrong type of fertilizer for a container grown citrus tree. You can use organic fertilizers for in ground trees, because the soil provides plenty microorganisms to break down organic fertilizers into a usable form, enabling the plant to use it. The medium of a container grown tree does not contain the microorganisms needed, therefore your tree is not able to use your organic fertilizer. Using a conventional fertilizer works much much better for container grown trees.

I would disagree that you can't fertilize with organic fertilizers in pots, however if you are going to do so you need to be diligent about how you care for your tree, use a medium that is appropriate for and encourages the growth of microorganisms, and avoid plastic pots. You also have to be careful not to use anything that can damage your microorganisms. When you use organic growing methods in containers you absolutely have to treat your soil as, as much of an organism as your tree, and I would not recommend it to someone starting out with citrus. (I grow my own trees indoors in a huge window exclusively under lights and use organic methods. I get fruit every year and my trees grow very well.) Reading your responses it definitely sounds like you have a few problems: water, light, potential overfertilization. You don't "feed" a tree the way you would feed a pet, fertilizer is not "food" in that way, but should instead be applied as necessary to replace nutrients depleted from your soil. Indoors, your trees won't deplete nutrients as quickly due to the low light and slower growth, so you don't need to fertilize as often or at all. As for watering, as mentioned above you should let the tree dry out between deep waterings and watch that your soil doesn't stay wet for too long. (For example: self watering planters are death for many indoor plants). As for lamps, the kind of grow-bulbs or nice looking growing lamps are not going to provide you enough lumens to grow a tree. You could probably use them for little plants that require low light, but a tree needs more than that. A high powered LED lamp is going to be your best bet for a citrus tree. There are options for ones you can install in your house or you could hide them in some way, but if you want your trees to do well you need a lot more light than a standard grow light. I hope this was helpful, and good luck.

The main issue with the Meyer is it is not loving its new environment and it‘s telling you so. I would reduce watering. With all those leaves gone, you're going to rot the roots because the plant will not transpire and draw up moisture. What is your house temp and humidity?

If you can lower the temperature, increase the light and also increase the humidity up to at least 50% then it would probably do better. However all those things can be difficult to achieve for most home owners.

If you can’t increase the light, at least lower the temp and increase humidity

The tree is 100% showing a nitrogen deficiency. The symptom for nitrogen deficiency in citrus is yellow veins on otherwise green leaf.

Bonsai-citrus. Concerning the use of organic fertilizers in container growing, you can also find on this form threads by Dr. Malcom Manners of Florida Southern University stating not to use organic fertilizers in containers. Many many members on this forum gratefully remember Dr. Manners knowledgeable citrus guidance.

I am not going to argue one way or another, I am simply mentioning that there are differing views on the subject and newer research which shows that it is possible. If it were not, I would have a number of dead trees and no fruit hanging in my window. What I said, and have said before, is that it is much more difficult and requires an organic approach from the start of growing your tree. Everything about your container needs to be set up to maintain the populations you reinocculate into your soil regularly. Like maintaining a sourdough starter you have to be aware of the details and feed your microorganisms. It's harder, more complicated, but not impossible. I usually mention it for those who are determined enough to do it, to know they need to do their research before they go ahead. I see a lot of gardeners on here saying they are using organic fertilizers in miracle gro soil and then wondering why their plant has a nitrogen deficiency. If you're using miracle gro, you won't be doing your tree favors dumping in organic fertilizers, chicken manure, and compost. You need to go out and buy an appropriate fertilizer and learn to care for your tree. More than that, you need to understand the appropriate application of fertilizer, understand light and water, and make sure that your soil is right for your environment. There are different methods for growing trees that are well documented and respected, find one, follow it, just don't try mixing things unless you really know what you're doing.

I used Miracle grow on 1 tree and my own urine on another tree for comparison 3 winters ago. The experiment lasted 3 weeks when my wife put an end to it. Chemicals vs Organics. who knows. I don't

^^^ I hope those were outside trees ;-)