Pictures!!!

Christina, considering I too live in Mass, can you explain to us how you transition your tree when bringing it from outside to inside? How much sun did it get before you brought it in? How much sun now? When did you bring it in?

Your mix sounds ok and your fertilizer does too..

Spraying with Neem to be on the safe side will not harm it as long as you follow instructions carefully...

Pics is a huge plus!

We must of been posting at the same time..Looks like mite damage underneath and it looks like you used too much oil...How much did you use?

If you can answer the questions above that will help..Looks like natural leaf drop from being old or light changes..

Yes, I didn't read well the instructions!! I washed all the oil off and sprayed the right amount the second time, it doesn't look like that now. The tree stays inside with the growing light I bought if it's too cold when I leave for work. If the temperature is above 50F I leave it out for the day. It gets a lot of indirect sunlight. Should I stop moving the tree inside and out and leave it inside?

What should I do?

Thank you Denise. I only water when it's dry

Christina, those other leaves look mighty fine and dark green. You must of been doing something right all year. Many times citrus will drop leaves, turn color or even get attacked by pests this time of the year. The cold comes into play. A lot less direct over head sunlight like summer and watering has to be pulled back dependent on the temps.. That leaf looks like it just naturally fell off.....Mike

When you sprayed with Neem, did you spray under the leaves too? Looks like you did the tops but not the bottom..

Thank you! Yes, when I sprayed the right way I made sure to cover the bottoms too