First off your friend should have never sent you the tree from Florida. There is a ban on exporting citrus out of that state. Sure it happens all the time and i doubt its an issue spreading the diseases that have caused the ban to Illinois, but it would do us and the law no justice if we dont educate people of the law.
I have heard of some rumors that nurseries are being able to ship out but for now its still the law.

Ok, now for the tree.
First thing Dont panic, meyers tend to get yellow leaves during the winter and will drop some. Your tree looks pretty good right now.

Second get rid of the glass ball. You need to control the watering not something else. You are correct that they want to get a bit dry before watering again. You dont mention what kind of soil you used but it very important that it does drain well.

Third, keep the roots warm, above 55-60 degrees if possible. It appears your tree gets good light. Good light equals the tree wanting to grow which means you need to keep it warm.

I wont comment on the fertilizer because I have never used it but i will say the most container growers go with a water soluble type in a 3-1-2 ratio, and add minor elements, calcium and magnesium if the fertilizer does not contain them

mike

Thanks Mike

I have to check how does the tree will react after 2 weeks without this glass watering bulb.
It might be a key.
Also some people says thatI souldn't keep tree exposed directly on the sunlight. So I've moved it to my book shelf (it's still pretty bright area - south exposure room).
I will also try use "soft" water to watering lemon tree and feed it once a month.

What is your opinion about grow lights ?? Should I use them to get more "light" to tree (up to 12 hours a day)

regards !
Pawel

Im not sure why anyone would suggest not exposing it to direct sunlight. Maybe if it had been in the shade for awhile and you needed to acclimate it to full sun.

Now having it close to a cold window with the sun blazing on it could induce leaf drop because of the roots not being warm but thats the only reason to not let it get as much true sun as possible.
Mike

what watt bulb are you using? if its a small bulb it may not be providing enough lumens. give it as much sun and light as possible. it will drop its leaved b/c of the change in the light.

water lightly.

Your tree needs as much sunlight as possible. I can't imagine why anyone would tell you to move it out of the window! Keep it in the window. Your potting soil needs to be well draining. You don't mention what soil you're using, but I would search our forum for "511 mix" and either use that homemade mix, or you can search for "Farfad" and use their Professional heavy mix. You do want your tree to get a good soaking, but to dry out some between waterings. Not too dried out ever, but never sitting with wet roots. That will kill your tree faster than anything. Ditch the glass ball. That's fine for other potted plants, but not really effective for citrus. For fertilizer, most folks use DynaGro Foliage Pro or Osmocote Plus (it MUST be the Plus formulation, not any other Osmocote product), or a combination of the two. Fertilize every month with the Foliage Pro. Grow lights are fine, no more than 12 hours a day, and the container folks can give you more suggestions than I can, since I grow citrus outside year 'round, and my container citrus stay outside :-)

Patty S.

It's a Meyer so you have to recognize its senstivities... Water it too much, it will drop leaves; let it get too dry and then water it, it will drop leaves; abruptly and significantly change its light conditions, it will drop leaves. The good news is it will recover from all of these, if you continue to treat it with TLC.

Thank you so much for all advices...
I'll let you know how on weekly updates how lemon is doing

:)