Orange Tree leaves curling upwards
Hello again. I have a 3 year old Satsuma orange tree that as of the last 3-5 days or so has leaves that are curving upwards. I did a search in this forum and read a post that suggested overwatering could be the problem. I checked the soil, and it seemed dry enough -- not bone dry, but not wet. I did the 3" finger test, and it came out fairly clean. I waited three days until the soil was even more dry, then watered as I normally do. I don't think its a drainage problem or root rot(though, how would I know for sure without removing the tree from its pot?)
Are there other reasons that the leaves would curl? Temperature change perhaps? The tree is in a Southern facing bay window, in a room that is heated by a woodstove. The temperature does vary during the days, but I've recently purchased a humidifier and I mist the tree once or twice a day, especially when the stove is cranking.
The tree was in the same location last winter and i don't recall the curling leaves then.
Any suggestions? I had been feeding it with Miracle Gro, but after reading this forum, I realize that there are better options. The only difficulty is that many have their favorites, and I"m still not sure what to use. Any suggestions on citrus food would also be appreciated....
Thanks again in advance for your advice and expertise...