Hello-

I'm growing a Meyer Lemon plant, and noticed some blackening of the ends of the stems happening. I've not changed anything recently, except perhaps there are some mild temperature fluctuations due to colder weather outside and then the heat kicking on. I keep my house at 70 degrees and the plant is about five feet from any windows, but under grow lights, so it is getting 10 hours of light a day. Below are links to the pictures I took. The first is the blackening that I'm seeing on the branches, the second shows where I tried snipping off the bad part down to a healthy area, only to find the next day the healthy end had begun to blacken as well. I don't see any visible insects or fungus. Has anybody encountered this before?

http://www.flickr.com/photos/11691760@N00/4006484645/
http://www.flickr.com/photos/11691760@N00/4006485263/

That looks like new growth that is being damaged. May be spider mites or some other insect causing the problem.

Citrus transpire moisture through their leaves to keep cool, and to draw ingredients up from the roots. New growth has a much higher rate of transpiration, than does the older foliage, therefore requires more water. If the damage is not due to an insect infestation, or disease, then the new growth must not be getting enough moisture. Is the tree setting near a heater, or in an area that receives a draft? Further if you are lilghting the tree, are you using a HID light such as a Metal Hallide lamp.? HID light put out a lot of heat. How close is the light to the tree? - Millet (1,190-)

I have seen this problem in the nursery before, but have never figured out what causes it. From my casual observations, it seems to affect only very succulant new growth and never seems to extend beyond the affected shoot.

Ned

gilsonal, if you are lighting your tree with a fluorescent lamp, then put the light approximately 2 or 3 inches above the tree. A fluorescent lamp that is 4 feet above the foliage will not be doing much good. - Millet (1,190-)

Hi, i got the same problem but in my case is extended in 3 branches , my lemon is under 2 CFL 23 w cold/warm light and is 5 inches above the lemon tree , moisture level in the soil is good 60-70%, moisture in the air is 50% and the temperature is 70-75 F.Light level on natural source is very poor.It is now 2 weeks since I last saw the sun, from the clouds.
I didn't see any bug on the tree and even after a close look-up with a magnif. glass.
Maybe is a fungus or something concerning the level of the moisture in the room.
When I looked at the tree and saw for the first time the blackening I thought that maybe is because I was spraying with water on the leaves.

Any ideea why?
Soory for my English

Thx very much

My Owari Satsuma is also displaying this problem on almost all of its new growth. I transplanted it into CHC a few weeks ago and have not watered it as much since it is cooler. Even in fall and winter, should I water more often if lack of water is what is causing this?

Also, will this dying off of the tips serve pretty much the same function as pinching off the tips? More growth of branches next spring?

It all depends on the formulation of your CHC medium. If your CHC medium is a blend of 4 parts CHC and 1 part peat moss, or even 3 parts CHC and 1 part peat moss, then you can water all you want with out any concern of over watering, as the above CHC blends cannot be over watered, due to the extensive amount of root zone aeration. It is not the water that causes a problem when a container is over watered, it is the lack of oxygen that damages or kills the tree's roots. - Millet (1,150-)