I've been growing citrus for over a year now. I've had my share of issues with scale and mites killing my stuff. All resolved, lessons learned. Now I have a new problem.

Have a look at these images. I cannot understand why I am losing leaves, followed by complete branches being dried up dead. This is exactly what happened when scale took out my other plants, but in this case I have verified 100% no scale or any bugs this time.

Details:
Nagami Kumquat
Indoors at 70 deg. in a south facing window
Watered weekly with Jacks 25-5-15
Keylime right next to it is flowering and happy
Meyers Lemon right next to it is also healthy

Do I have a ROOT problem? If so, why? CHC medium should not create too many issues with roots and watering, etc. I am using Millets famous 4-1 ratio CHC + peat.

Key Lime (happy & Flowering), Nagami Kumquat (Leaf Drop + dying!), and Meyers Lemon. (Lemon is healthy, ignore its dead branches, that was from scale, all resolved now, hoping to recover!)


BTW, the leaves you see above are dropping daily. Oh, and that vent in the floor is closed to minimize heater draft.

Nagami Kumquat, branches on left dead and brown, branches on right just dropped leaves, are green and becoming brown, likely dead in a week.
[/img]

It is just my point of view:
Maybe at that temp you have the WLD simptom caused by the low temp in the soil and high on the leaf surface.

Also what I noticed in my experience is that if the branch does not recover and start new leaves it will finaly dry out , perhaps it is a lemon problem caused by self protection.A branch with no leaves has nothing to offer to the tree itself so he will no longer provide food to sustain that branch.

this is how I see it

Good luck on recovery

I'm listening. Will check soil temp. But in the meantime... kinda brewing over this in my head. How can the soil/root temp be too low in an indoor pot?

I believe kumquats are more sensitive to low humidity levels. I've had a number of them die on me before I raised the levels in the plant room.

Where are you? Kumquats are some of the most cold hardy citrus.

Seattle.

It's been a horrible spring, too cold for outdoors. My plants sit south facing indoors. So again, low temperature is not a factor at the moment in this case.

Soil temp is 70 F.

Seattle is indeed a humid place. But I think we may be on to something here, Junglekeeper. It doesn't mean indoors is as humid. I had not considered an issue though. We're riding between 30-40% humidity in the house at the moment.

I added a humidifier by the sad tree to see if it would appreciate it even higher.

Update:
Interesting. The day I added the humidifier, the leaf drop stopped and the plant appears to be stable again.

Weird though... this has to be only coincidence, because of the latency of citrus. Meaning, citrus is slow to visibly react to changes... ie, todays behavior shows how it was feeling a week or two ago, no?

Soil temp of 70 is certainly not the problem. Humidity could be one factor, but changes in light level could also be involved. I understand it is often cloudy in Seattle, if the tree was growing in more light and moved into a low light environment it may reduce the leaf load to adjust.

A quick update here...

It hasn't dropped any leaves since my last post! All is well. It's outside in the Seattle summer now (we have ACTUALLY had SUN for a couple weeks now!) and it is doing pretty well. BTW, leaf drop stopped before I moved it outdoors, just to be clear.

I wonder if it was a lack of watering, plus low humidity (which is now fixed). I've been avoiding watering for fear of root rot (see this post) for 3 weeks at a time. I am now watering every week again, mainly because it would bake in the full sun otherwise.

Kumquats, always react poorly when not fully watered, more so than other cultivars. A Kumquat appreciates a good soaking every now and then. When you see young twigs dieing back, increase your watering. Young twigs struggle trying to compete with larger branches for their fair share of nutrients, water, and light. - Millet (901-)

How about lack of sunlight? Your spring/summer has been very cold and rainy. My brother said it has rained for 6 months. Hmm, my mother said it was 58F today.

Most people not having lived in Seattle can't comprehend the weather there. Me, I grew up there but wanted to live in the sunny South. So here I am in SE Texas.

Lack of sunlight this year indeed. We had the most rediculous winter/spring/early summer. Rain, rain, overcast, more rain. No shred of sunshine until late June if I remember right.

The Kumquat was indoors during that time, but thats even more reason for it to be upset - indoors and constantly overcast for over 6+ months - not a good combo.

I am planning on a greenhouse setup next year. Pathetically, I am designing for artificial lighting INSIDE the greenhouse as a suppliment due to the above patheticness of the Seattle area.

Yes, Seattle weather is as bad as the rumors and hollywood portray. It is green here, but not with anything tropical!