Thanks so much, and no, I'm not in zone 10. That is the default for posting and I didn't bother changing it. Sorry I did not give enough information. I am pretty sure it's not getting too much water as I notice the leaves curling every so often so it must be more dry than optimal. I usually give it at least a gallon/week (very large pot). It is in a full wall-height south-facing window so gets as much as possible. It definitely did experience a big change coming from outside as it was pretty chilly by the time I moved it. Please give guidance as to what type of fertilizer I should use and where to buy it, thank you!!!

Well, shortly after the post, I realized I needed to take action, so I repotted both lemons right away. They were originally put into 12 inch terracotta pots, but I reduced the size of one to a 10 inch terracotta pot (the second stayed in the 12 inch). When I trimmed in the original potting, it was less than an inch off the bottom. I repotted with 1/3 part of cedar shavings (as recommended by Four Winds Growers) and gave them a GOOD SOAKING of water. The roots were quite dry, no root rot had set in, and they were very healthy. The roots looked the same as when they shipped 6 days prior. The GOOD NEWS: the next day after repotting and heavy watering, a few of the buds opened up! They smell fantastic. I imagine the plant wouldn't open buds if it wasn't bouncing back? They've also bee in full sun since Sunday. There are still some yellow leaves, and I lost a few more (maybe 1 a day from each, rather than 6+ a day from each), but I take it they're recovering? After seeing the buds open up, I gave a light feeding and another watering today. We're having night lows in the 50's, so I'm leaving them outside at night now too. Are they on the mend?

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

Sometimes those cactus mixes can be hydrophobic or retain water. I'm guessing yours is the latter. Go back to Home Depot and get perlite you should be able to find it in the soil area. It's cheap too:). Do a mix of 50% perlite and 50% C&S soil. Use more perlite if you have a heavy watering hand. This should help tremendously. Goodluck:) I love Opalinas also;)