Lime tree dropping leaves
I realize a few posts have been on this topic already, but it wasn't quite the same situation, so I'm starting fresh.
I'm a Florida native transplanted to Omaha, NE, and I've wanted to have a key lime inside for a while. I bought one last summer, and brought it up here. It spent the summer outside, and did great.
This winter, I repotted it to what will be it's permanent home for a while (c. 12" diameter pot at top), and brought it indoors before the frost. It was fine till about January, when it started to drop some leaves, but not badly. A few leaves didn't alarm me, as citrus do that. By late February, the leaf drop moved to critical. It has less than half the leave it had in autumn.
I *think* it may be a water issue, but first, what I've done:
--Key lime was repotted specifically in Florida sand-dirt that I dug out of my father's lot to make it happy, with moss on the bottom, to help drainage. So it's NATIVE soil.
--It has it's own grow-lamp inside, and I put it in a corner away from all windows or doors, so no cold drafts. The house never drops below 60 degrees at worst (usually 63-64). So it's not cold and it doesn't lack light.
--I've ordered citrus food, but until I got it, I gave the lime both coffee grounds and Epsom salt, for the minerals. One bout of Epsom salts, two of coffee, a good month apart.
--There is no evidence of pests, and the leaves show no yellowing or spotting. they're still pretty dark green when they drop. That's why, at first, I wasn't worried, but after >50% drop, that's ridiculous.
--Watering MAY be the issue, as it's what I'm least clear on. Last summer, outside, the lime got a dose of water every day when I watered my flowers, and it loved it. But it was outside, with summer evaporation.
Inside, I'm not doing that. I started out watering it every 4 days or so, but around January, the leaf drop started...not bad at first. By mid-February, it was getting notable. I went online to find a solution, but found instead debated advice. I tried cutting BACK on watering, and the leaf drop started getting critical.
Then I tried watering every other day, and that made no difference. It's still bad.
After all I've tried to do, I don't want to lose my lime tree! My father left Florida (he's 89) to live with my brother in KY, so I don't have a chance to get a new lime tree. I have to save this one. I've done everything I can think of, but the poor thing is still dying!
Today is was over 45 degrees, so I put it outside to get some sun. Tomorrow it will be even warmer. But I need help on how to keep it happy INDOORS.
As noted, I have it potted in Florida dirt, drained, a grow lamp, citrus food as directed, and it's out of winter drafts. I just need to figure out the *proper* watering schedule, I think.