I'm not an expert, but I might guess it isn't getting enough light. If it can't make enough food, it can't support leaves and branches. It could also be overwatering. If your mix doesn't dry out the roots can rot.

I had a similar problem with my kumquat last winter under a florescent grow light with no natural light and found that it was due to the lack of light. Leaves were drying out, falling off green and lower twigs were dying off. It looked pretty sad before recovering in spring outside.

This winter I moved it to a east facing window with a two lamp, four foot florescent fixture above as well as a 42W CFL to the side and its doing fantastic. It bloomed shortly after bringing it in and has since set lots of fruit, Its even putting out a growth flush right now on the window side of the plant. The new leaves coming in look nice and healthy but are 2-3 times larger then the small summer leaves so its still not getting ideal light and I will probably need a better setup for next winter.

If the branches are brown and dead they should be pruned back to where it is still green and alive

also you don't specify what kind of soil you are using. peat based and most other store bought potting mixes (even those that say "for citrus") are bad for citrus because they have poor drainage which will result in root rot and the decline/death of your plant. I recommend the gritty 1:1:1 or 5:1:1 mixes that you can look up on this forum. Its almost impossible to over water these mixes.

You also need to flush your mix every so often to remove any salt build-up that may be occurring in your mix which can also damage your plant. This can be done by placing your pot in your tub and watering it until water starts to pour out the bottom. I would recommend doing this at least once every month.

This post was edited by TheRiGuy on Sat, Jan 10, 15 at 1:40

"You also need to flush your mix every so often to remove any salt build-up that may be occurring in your mix which can also damage your plant. This can be done by placing your pot in your tub and watering it until water starts to pour out the bottom. I would recommend doing this at least once every month"

That might be good enough for 1-1-1 or 5-1-1 mixes but not normal potting mix. I have a ppm meter and was surprised to see that it takes a lot of run off to get rid of buildup. So I googled. Marijuana growing sites popped up when I typed in flushing soil. I figure most of them would be using ppm meters because they really go for maximum growth and make so much money off it that as a group they can afford all the proper tools. It seems they do. They confirmed that it can take up to 5x the soils volume of water to fully flush the soil of old nutrients. Turns out peat based mixes have a high cation exchange capacity. That means that not only does it get absorbed into the peat along with the water, it actually chemically attaches to the peat. That's why you can flush with clean water to a low ppm and check a few days later and have a higher ppm.

The worst part is it can be selective with nutrients. That means the nutrients balance will still not be what the fertilizer's is.

Thank you all for your replies.

I've pruned the dead branches and for now I've not seen any other branches or leaves drying and dying.

It was fairly warm and sunny today (12 C), so I've put it outside in hope it will get the needed light.

I am not sure about the potting soil, it was there when I bought the tree. If the problem continues, should I buy new soil and repot the tree?

Thank you!

Overwatering leading to root rot leading to inability to take up water leading to eventual death of the tree.

Berna

When I started thinking of growing citrus trees 3 years ago I narrow down my choice to growing Meiwa kumquats only. I am curious to see pictures of your tree at best an worst. 2 of the last 3 of my seed grown kumquat trees have died and the 3 tree I found a new home for. I started out with close to 300 trees. They were very hard to grow. I will get a picture of meiwa at its worst (Right now) later tonight if my flash works, or tomorrow if it doesn't.

Thanks Steve

This post was edited by poncirusguy on Sun, Jan 11, 15 at 18:44

Most of the time leaf drop is when the soil is too cold and or to low of sunlight. If your soil temperature falls below 55 degrees the roots stop working and thus can't support the leafs so it drops leafs to cope with the loss of root function. Even my trees that stay in the house where it stays 70 degrees year around. On really cold nights the pots that are on the window seal will get colder than 55 degrees. In the winter when I water I mix some warm water with cold water to get 85 degree water. The 85 degree water warms the roots up so they can take in the water and nutrients you're giving them. If u do this Is it very important to make sure the water is not above 85 degrees. If the water is too hot you will kill your plant I use a digital thermometer that is very accurate to make sure the water is not too hot. By doing this I have almost zero leaf drop when I bring the trees in or put them in my greenhouse for the winter. I hope this helps I'm not the expert but this is what I have learned.
Trace

Hello again and thank you for your replies.

My house is warm, around 25 degrees Celsius (77 F). I've read though that citruses do fine on temperatures around 10-12 C (50-53 F) and that is why it spent yesterday outside in the sun. Today is cold and rainy and it will stay inside.

This is the tree when I bought it

{{gwi:2124422}}

I'll need to take another picture how it looks now, it has much fewer leaves which isn't really noticeable from this picture:

{{gwi:2124423}}

I will take another one when I get home.

Thanks again.

This post was edited by Berna22 on Mon, Jan 12, 15 at 4:01

Meiwa has survived and is at her worst ever. picture below is of the same tree above

Steve

Mine doesn't have yellow leaves, but as you can see, it has lost many of its leaves since July. :(

{{gwi:2124424}}

Wow Steve please raise your kumquat its really tough.
Trace

It's me again. Now I know that a part of the tree is dying. It's been warm and sunny this last week, and I don't think it has to do with lack of sunlight or the temperature in the room.

I've changed the soil. Trimmed the roots. They didn't look unhealthy, but what do I know.

As you can see, the left part of the tree is pretty dead.

Any suggestions?

{{gwi:2124425}}

Pick the fruit and do not let it set new fruit. This will allow the tree to grow in roots and foliage. My tangerine tree is lopsided like your kumquat. The tree will do just fine and eventual fill out.

Same tree 5 months later. It sent out many new shoots to fill in while extending height on older main trunk. The fruit will take all the energy and the tree will not grow. The wooden box has been removed and more dirt added.

This post was edited by poncirusguy on Sat, Jan 17, 15 at 9:31

Thank you. I hope you are right and that whatever it is won't affect the other part of the tree. If I knew it, I'd have picked the fruit earlier.

If the fruit is not quit ripe it will taste more like a lemon and you can make a kumquat meringue pie. Kumquats are so hard to grow because they do not go dormant and you are growing them in an area that is best suited for tree that sleep. Kumquat trees grow slowly so they have less vigor to battle what ails them and when they die back it take longer to regrow. Also you live so far north I am not sure the bottom half of the sun even come above the horizon.

Best of luck to you

LOL it's not that north. ;) I believe we are at the same zone.

Thank you very much for the advice.

Steve is right kumquats dont like winter I'm north-mid GA and they still have fits in the winter.
Trace