Has it always been in that pot? If so, I suggest moving it into a bigger pot.

yes, it's always been in that pot. It's about 16.5" at the top X 16-17" tall. How big should the pot be?

Its not that the pot is too small, I am just speculating that it's roots may not have room to grow. It's a good idea to re-pot into something bigger every year (or 2).

The tiny white spots on the leaves indicates you might have spider mites which are too small to be easily seen by eye. Use a magnifying glass to see if there are any. If there are mites, then treat with insecticidal soap or horticultural oil (or neem oil).

I can not tell if the pot is of appropriate size but the real problem with that pot, because of its shape, is you will have difficulty getting the root ball out when it comes time to repot.

Would the spider mites cause the leaf drop?

A hammer will make it easy to get the pot off. 8^)

I've treated the tree with neem oil once. How many times do I have to treat with neem oil? If the tree has to be repotted, I can do that and treat with neem oil at that time. The nursery I bought it from said I shouldn't have to repot for a long time. I don't mind repotting it in a larger pot, but I don't know if it needs to be repotted every 1-2 years, does it?

How often it will need to be repotted will depend on the soil mix. A peat-based mix (most commercial bagged potting soils) breaks down rapidly and starts to compress or collapse so these should be refreshed or soil replaced on an annual basis. A more durable, bark-based mix can last longer. And all container grown trees will need root pruning periodically as well. Unless you choose to up-pot every time.

where are you .... since its indoors.. its a cold place.. what type of furnace.. whats your indoor winter humidity ... is the window south facing ...

trees are not houseplants ...

i wouldnt fertilize a tree in winter ... it should be in slow motion during winter slo down ...

BUT!!!! ... this MI boy has no citrus background ... maybe those are fert'd in winter.. when indoors ....

no tree holds its leaves forever.. they are shed as they age ... so part of the shedding is normal ..

ANY stress to the tree can cause increased shedding ... like significantly reducing sunlight by bringing it in the house ... transplanting/repotting it ... smearing neem all over it ... etc ... etc ... perhaps significantly low indoor winter humidity also ...

bottom line.. its a tree .. its not a houseplant.. it should be outdoors ... you cant really change that equation by trying to grow citrus in a cold climate on top of that ...

anyway.. its been thru all kinds of stresses ... plus you might have bugs ... and delineating which thing put it over the top ... might never be answered ...

BTW .... do you let it near dry.. between waterings.. trees prefer a sip of water .. full drainage.. and near drying.. between waterings ...

good luck

ken

ps: why the heavy mesh over the pot.. and whats the plug for near it.. in the last pic ...

... and not to mention ... yoda like stream of consciousness ... or brain waves , etc, etc ...... or thoughts trickling ... whatever ...

!! usually I skip ... such disjointedness ... no ill intention ... just having some fun .. see ya ... enjoy !!

To the OP: I do not see any pest problem. But check under the leaves and stems for signs of pests. Usually at this of the year house plants react to increasing light. It is also time of the year for tropicals to wake up to produce new growth and shed some older leaves. But yours seem to be shedding new leaves too. It is likely the problem lies in the soil and your watering habits. Perhaps compacted soil with accumulated salts over the winter.

If it is ready to go outside in your area then do it. Keep it in open shade for a week or two. If it is going to rain let it soak well. Otherwise flush the soil: Water it several times with plain water (rain water will be better) and let it drain out well. This will flush your soil of accumulated salts. After that give it a 1/4 to 1/2 strength fertilizer and do not water till it is quite dry.

Thank you to everyone. I live in central Arizona, south of Sedona, but well north of Phoenix. It gets very hot in the summer, but can snow (like this year) in the winter. The mesh over the pot is to keep my cat from digging in it. I didn't like finding piles of dirt on the floor, plus it can't be good for the plant. The plug is for a grow light I have attached to a pole. I didn't use it much this year. I have a number of orchids. They seem to be doing ok w/o it, and I got it primarily for the orchids. But the room has windows on 3 sides, and the tree is next to a North facing window. I have beautiful views so I leave them uncovered during the day. During the summer, it stays on my patio (also north facing, and covered). It's too big for me to move it back and forth a lot. When I water it during the winter, I watch for the water to seep out into the dish, then stop. I usually water again when the dish is dry.

I don't think it's shed any of it's new leaves. I'll check under the leaves for pests. I still don't know how many times to treat with neem oil. I didn't smear it on. the leaves. I diluted per pkg instructions and used a sprayer to spray it on.

This picture is of the mesquite trees behind my house covered with snow, but the snow was gone by the afternoon.

I think I see some branches dying back so I am thinking it's the soil retaining too much water. What type of soil is the tree in? The time to water is when the top 1-2" of soil is dry.

This is the time of year for the trees to be shedding, so some of it may be for that reason. If your new leaves are doing it too, then you have reason to be concerned.

A good pot to use is one that has a wider opening at the top so the tree can be taken out to be examined easily. I am wondering if the pot and drip tray are one piece and am concerned about the water not draining away well enough. The roots may not be getting any oxygen from the bottom. I would check the roots to see how they look in case there is root rot just to be on the safe side. If you have another pot which has more holes at the bottom, I would switch it out.

I can't tell if there are any bugs for sure as my computer won't blow up the photo. If the leaves are sticky, then yes spray with neem and then reapply 7 days later. Mites are tough to eliminate inside the house as they seem to return fairly quickly. I am fighting rust or some sort of red mites myself.

Citrus trees should be fertilized during the winter with a liquid fertilizer at half of the recommended strength. The organic granules don't break down during the winter. During the growing season, do it monthly with a citrus fertilizer. What type of fertilizer did you use?

Arizona's Best, a dry fertilizer now. At first I gave it some organic fertilizer, also dry, that had very low numbers. I'll buy another pot for it, larger. I think the leaves are sticky. I don't know what kind of soil it has. I'm disabled and leave most of the gardening, including the potting, to a gardening guy I use. He said the pot had lots of drainage. It';s made of some kind of plastic, and I asked him to drill holes for drainage in it. It's not part of the dish below it. I didn't fertilize it over the winter, but I did give it some fertilizer in January. The new leaves that recently came out are much larger than the old ones. There are a number of bare branches, though. When it's repotted, I'll check the roots. It's an Oroblanco, and the fruit is very delicious. I only had one fruit this past year, and it seems that all my fruit has fallen off, so I don't think I'll have any this year, but I want to take care of it. When I put it outside, it's on drip irrigation. We have water restrictions here, so I am supposed to water only 3 times/week.

Even with the very rare snow, I'd still consider planting it in the back. Snow will actually protect leaves from a deep cold. The only thing that would make that a bad idea is if the daytime highs stay below 45 for more than a month in your area. In my area the daytime highs go down to around 45 for about a week or three in January.. sometimes longer but I'm pretty sure it's never consistent for over a month. All my citrus (even the lemon trees) are fine with it. It helps if they are already established by the time the deep cold comes, and some protection the first few winters (just put a blanket over them that reaches the ground on all sides on very cold nights).

I think the current issue with your grapefruit is most likely the watering issue that gardengal48 pointed out. It could stay in that container longer but I wouldn't keep it in there much longer considering the roots are probably already circling the sides. Keep in mind the first time you water it after it's been fully dried out, the soil could have become hydrophobic, which means the water will just start running out of the bottom when you water it. If this happens you need to dunk the whole pot in water for a while to get it to absorb water again.

"When I water it during the winter, I watch for the water to seep out into the dish, then stop. I usually water again when the dish is dry."

Right there is one of your biggest problems. Never leave water in the dish. You are correct in watering it until water starts to flow into the dish, but then you have to empty they water from the dish. You wouldn't like walking around in wet socks all day and citrus trees do not like "wet feet" either. Letting it sit in a dish of water will lead to root rot which is probably what is causing your leaf loss right now.

I'm disabled, and can't move the tree. It;'s too big for me. I'll try to use the method suggested by Denise Becker next winter and check the topsoil. When I water the orchids, I let them drain over the sink. It helps a lot. I know what you're saying, Ken B.

I'm afraid to plant it in my yard. It's really cold in winter up here. Do you live near Phoenix, iandyaz? Besides, I live in an HOA and they require approval for planting any trees. They don't want the views blocked. I have really nice views, but I don't have many other spots in my yard to plant a tree. As it is, my lilac bush isn't blooming, and I think it doesn't get enough light. I've been struggling with an idea of where I might move it.

Patti, you do have another option. You can do a root and canopy prune so that the tree can stay about the same size and is manageable for you. Another thing that may come in handy is putting your tree on a plant dolly so you can move it around if necessary. I use the Down Under Plant Dolly myself which can be purchased online at Home Depot. There are different sizes.

Your new leaves are larger than normal because it's the plant's way to capture more light. Think of it as a solar panel. Trim off the brown branches a little past green tissue so the tree doesn't die back more.

If you have good lighting, well draining soil, and a regular fertilization schedule using a citrus specific fertilizer, you are good to go for this year.

Denise, how do I prune the roots? I understand pruning the canopy. I have a polly underneath it. The first one wasn't very good, so I found another with six arms on Amazon that seems to be much better.

polly shd be dolly

I found a 20" clay pot at a local nursery (It has a dish, separate). That should be big enough, shouldn't it?

Patti, I suggest going with a plastic pot as the clay pots add unnecessary weight especially in your situation. I know the benefits of terra cotta but still prefer the plastic. If the pot falls over, it doesn't break. Add extra holes if you can.

Root pruning is pretty simple. You just cut off roots on the sides and the bottom and refresh the soil. Here is a video of how this person does it, but I just cut off 2" off mine, roughed up a bit the sides and was done with it. My trees did fine. https://www.youtube.com/watch?v=nzNZEH0NOEU

I noticed that there is a sticky, sweet liquid coming out of the branches. Is that caused by red mites too?

If it's an amber color product coming from the actual branches, it could be gummiosis. If it's actually on the leaves, then the cause could be spider mites or some other pest. A picture would help.

I'll try to take a picture of it tomorrow. Thank you.

There was enough light to take pictures today. I think the liquid IS amber, and a number of branches have it. The leaves seem ok, except if they're under those branches.