Why do you need to water every 2 days? Maybe a banana plant would like that much water but citrus may not. How long have you kept that watering schedule and is it a light misting or deep watering?

I've been using a 1000 watt metal halide light since my trees came inside around November. The temperature in the room can fluctuate between 70 and 95 and the humidity between 30 and 50% due to a humidifier and misting. I crack a window to try to keep the highs below 85.

I originally had my trees in regular plastic pots. I would water every four days even though the bottom of the soil would still be a little wet because the leaves would show signs of stress. I didn't have this issue when the trees were outside so I assumed it was because of the high temperature. I couldn't think of a way to lower the temperature or increase the humidity so I replanted my trees in air pots (root pruning) so the soil would dry out faster.

I watered every three days after I switched pots. However, I waited too long one time. I think I waited four days but it could have been five days. My grapefruit tree (which is the tallest) had severe leaf and branch loss. I've since started watering every two days just in case I lapse in watering again.

My grapefruit tree recently started a lot of new growth- mostly water sprouts. My lemon put on a lot of new growth recently too and my lime is just starting to grow again. The lemon is the one with the "severe" yellowing. However, a few leaves on my lime tree fall off every few days too, but the new growth from the past few months is fine. My grapefruit isn't yellowing at all but it is a lot bigger and older.

Could the leaf loss could be from the switch from outside to inside conditions? I had problems when I originally brought my trees inside in November but I thought that was over now. Perhaps I should switch back to watering every three days? I just think its odd that I get yellowing on my Meyer a few days after new growth. Is that a sign of over watering? I don't have these issues on my other trees (orange, kumquat, pumelo, etc. ) that get watered at the same time. But they also aren't growing as fast.

Does anyone know why the lemon shows signs of over watering but the others don't?

I don't know about over watering. The point of these freely draining mixes is that you *can* over water them and not feel very guilty about doing so. Since your leaves have yellow veins, the tree is sucking the nutrients out of the leaves (probably to better acclimate to the 1000 W MH, mine does the same). When you put them outside, this process should stop.

-Tom