Potted orange tree leaves curling and falling off

In late spring I have bought a potted tangerine tree. After a few days, some of the leaves stated curling and falling off, but some leaves fell off without being curled. As soon as it warmed up, I started bringing the tree outside during the day and left it outside all day in mid summer. It did great and new leaves came out and even some flowers. At the beginning of the fall I brought it back inside and the curling and falling leaves issue started again. I am not sure if it is over watering , under watering , temperature or any other issue. The tree is in a room facing East near the windows and I have closed the vent in that area. I have fertilized it with Miracle Gro once in the summer.
Can anyone help me with some advise on this issue please?

 

If the tree has been in the container for awhile, it should be fairly easy to ease the rootball out for inspection. Check the condition of the roots. There should be some fleshy, light-colored roots. Mushiness would indicate root rot. Also note the amount of moisture in the container. The medium should be evenly moist but not wet. With the tree back in the container, pick it up and feel the combined weight. Based on that you should be able to tell when the tree needs to be watered in the future, keeping in mind that citrus prefers to have soil that is somewhat dry between watering.

Citrus should be placed in a well lit spot. Move the tree to a spot behind a south or west facing window, if possible. Actively growing trees should be fertilized on a regular basis according to instructions on the product label.

Regarding the leaf loss, does it stop after a short period after the tree has been moved or is it continual?

 

Thank you for your response. I have inspected the roots and I've found the soil wet at the bottom quarter of the pot and some mushy roots. I have removed all the damaged roots and replaced some of the soil. I have also purchased a mo8ture meter and now I make sure the soil moisture is average. The leaf drop has decreased significantly, but it still looses a couple of leaves per day. Is there anything else I should look for?

 

I have no experience with fruit trees, am only writing to agree with Junglekeeper that picking the plant up and feeling the weight is a better indicator of when it needs water, or sure, use the water meter as well, but I have found water meters unreliable.

If it is doing significantly better, then maybe not worry about a few leaves - it would not heal instantly and now it has had a bit of a shock. At our latitude, would it want to be deciduous, or at least go dormant in the winter ( maybe for someone else to answer )?

 

The root rot was a problem but it may not be the cause of the leaf loss. With root rot the leaves tend to wilt as a result of the tree's inability to take up moisture and you have not noticed such happening in your plant. Is the tree located in spot where the temperature is low at times, perhaps next to a window? Low root temperature combined with exposure to light will result in leaf loss.

What is the condition of the leaves that were shed recently? Do they look healthy or are they yellowing? Do they have an attached leaf stem?

@wcutler
It would not be desirable for a citrus tree to be deciduous. It is possible to force one into dormancy but that requires the tree to be placed in a dark place for the duration.

 

I have noticed several types of falling leaves issues:
- healthy (?) leaves , stem falls also but separately from the leaf
- curled leaves
- leaves with some rust spots.
Most of the times the stems fall at the same time with the leaves, but they are separated
I have also noticed some tiny white spots, so I have sprayed the tree today with Bug-X (insecticidal soap).
The last thing I have noticed is that most leaves are two tones of green, which I am not sure if it is normal.
The tree is next to a window facing East, but I have a thermometer that reads 21.3 C at top and 22 C at the bottom of the pot (inserted approx. 3" into the soil).
I will attach a few photos for reference.
Thank you again for all your help

 

I just noticed also a few tiny black dots, seems like a bug to me.

 

Under normal circumstances leaves fall with the petiole attached. When leaf loss is due to stress the petiole remains attached to the tree stem. It will eventually be shed as well of course. Some of the leaf loss could be attributed to the sudden change in environment from moving between indoors and out. However that should stop once the tree has acclimatized. The slight curl to the leaves could be because the tree has not yet recovered from the root rot. In any case it doesn't appear to be severe at this time.

The tree looks pretty good overall. I do not see any obvious problems. There are shiny spots on some leaves but that could be from freshly applied insecticidal soap. If not, is it sticky? Is the substance also on your floor? If so, then there could be an infestation of a sap-sucking pest in its early stages. I see some white specks on a leaf in center-left of the last photo. Could they be white flies? A few leaves underneath appear to be discolored which makes me somewhat suspicious. The debris on your finger appears to be an insect, perhaps an ant or small wasp. I wouldn't worry unless there were live ones on the plant.

I suspect there won't be sufficient light from the east window; you may need to get supplemental lighting if the tree is to remain where it is. The temperature won't be a problem until it approaches 13C, at which point the roots will cease to function. As mentioned earlier, the tree should be fertilized regularly while the tree is actively growing. Make sure the fertilizer contains micronutrients. That should address any minor deficiencies the tree may have.