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  #1  
Old January 1st, 2007, 08:41 AM
orangetree orangetree is offline
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Orange tree in danger..help..leaves falling off and branch tips brown

I have an ornamental orange tree that is 3 yers old. It has doubled it's size in the time we have had it, but every year when we bring it inside for the season we have one problem or another. The tree is now about 3 feet tall with a lot of oranges on it. It looks great, but it losing leaves at a quick pace and the stems are turning brown. Last year in the in the winter we suffered with spider mites so this year we were sure to treat it before and after bringing it inside. The room it is in has good lighthing and is warm. I don't think it is a cold root issue..could it be overwatering? That is what I've been reading here. If this is the problem, how soon will I know. I don't want to deprive it of water and cause another problem to occur. I don't see anything else wrong. It is getting new leaves..but some of them also fall off. Just running my hands over the plant will can cause 10-15 leaves to just drop. I examine this every day looking for clues. I am at a loss. Today I found 3-4 leaves that are mis-shaped. If yo look at them sideways, they would resemble 'smiling lips'. Could this be a clue. I am really worried. I did put to plant fertilizer stakes in the pot when I brought it inside. Could this be the problem? It flowered a LOT when we first brought it inside..but since then it has only been losing leaves and fruit..daily. It is in a clay pot. Any help would be greatly appreciated.
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Old January 1st, 2007, 05:43 PM
skeeterbug skeeterbug is offline
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Re: Orange tree in danger..help..leaves falling off and branch tips brown

You can check the roots by laying the pot on the side and sliding the plant out to look at the roots-- if they are yellow/white and firm they are fine-- if they are brown and mushy -- you have root rot from overwatering.

Last edited by skeeterbug; January 2nd, 2007 at 05:02 PM.
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Old January 2nd, 2007, 09:09 AM
Millet Millet is offline
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Re: Orange tree in danger..help..leaves falling off and branch tips brown

Its much less serious to under water a citrus tree than it is to over water a citrus tree. With symptoms of both leaf drop, and twig die back, it certainly sounds like you are keeping the soil too wet. You say you do not think it is a root temperature problem, but have you actually measured the temperature of the root zone with a thermometer? "Absolute Zero" for citrus roots is actually a rather high temperature. - Millet
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Old January 2nd, 2007, 05:47 PM
orangetree orangetree is offline
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Re: Orange tree in danger..help..leaves falling off and branch tips brown

HI and thanks for the reply. I examined the roots and they are white, so I was glad to see that. No..I have not actually measured the temperature of the roots, but will try that next.
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Old January 3rd, 2007, 07:50 AM
skeeterbug skeeterbug is offline
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Re: Orange tree in danger..help..leaves falling off and branch tips brown

That is a good sign, the 2 most common causes of leaf drop are overwatering and cold roots. As Millet has told us on many post, citrus roots completley stop all function at 55.4 F and they are barely functioning at temperatures in the upper 50s. If the leaves are exposed to direct sun during the time that the roots are not functioning, the leaves will dessicate while trying to cool themselves by transpiration.

There are 2 options for curing the problem, heat the roots to at least mid 60s, or remove the tree from direct sun.

Skeet
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Old January 3rd, 2007, 07:37 PM
orangetree orangetree is offline
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Re: Orange tree in danger..help..leaves falling off and branch tips brown

Thanks. Is there a time frame for when I can expect the leaf dropping to stop. Also, is the other condition root rot curable?
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Old January 4th, 2007, 08:28 AM
skeeterbug skeeterbug is offline
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Re: Orange tree in danger..help..leaves falling off and branch tips brown

A tree with root rot can be saved. This usually requires repotting, cutting away any dead or infected roots during the process and if the root loss was very significant, pruning the top to match what the roots can support. The potting medium should be relatively coarse, drain well, and not have too much peat. Citrus roots need lots of air and as the potting medium breaks down and compresses the soil retains water and can't hold air, leading to root rot.

Skeet
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Old January 4th, 2007, 08:31 AM
skeeterbug skeeterbug is offline
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Re: Orange tree in danger..help..leaves falling off and branch tips brown

I forgot to answer your question on the leaf drop-- if exposure to sun while the roots were cold was the problem, leaf drop should stop soon after the tree is removed from sunlight or tthe roots are heated.

Skeet
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Old January 14th, 2007, 08:58 PM
orangetree orangetree is offline
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Re: Orange tree in danger..help..leaves falling off and branch tips brown

Leaf drop has not stopped. I think possibly this tree may have outgrown it's home and may need to be repotted. Could this be the cause of my dilemma. When inspecting for root-rot, there were plenty of WHITE roots..mostly roots now that I think of it. Today I realized when feeling the soil that roots are starting to come to the surface.
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  #10  
Old January 14th, 2007, 09:37 PM
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Re: Orange tree in danger..help..leaves falling off and branch tips brown

Low humidity may be your problem. I've experienced leaf drop and stem dieback in the past when levels dipped below 40% for an extended period. The level can be checked with a hygrometer.
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Old January 15th, 2007, 08:28 AM
Millet Millet is offline
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Re: Orange tree in danger..help..leaves falling off and branch tips brown

It has only been approximately a week sense the tree started to drop it leaves, it is not all that uncommon for the leaf drop to have not yet stopped. If indeed the tree's problem was caused by the stress of high foliage temperatures, and low root zone temperatures, that stress cues the leaves to reduce the production of a hormone called auxin and to increase the liberation of ethylene. Ethylene stimulates an enzymatic breakdown of the cellulose walls and pectin (the "glue" that holds cells together) to a narrow band of cells in the leaf called the abscission zone. Once senescence has started in cannot be reversed, and the affected leaves will continue to drop. Usually in these types of cases not all leaves are affected if the situation is caught in time. There are two abscission zones for citrus leaves, one at the bottom of the petiole (leaf stem) for normal leaf drop, as in the case of the discarding of older leaves, and another at the bottom of the leaf blade when abscission is caused by certain types of stress. In the latter case, the petiole remains attached to the branch. In answer to your statement, all citrus roots show on the soil surface. In fact a properly planted citrus tree, whether in the ground or in a container, should be planted so that a little of the tree's upper roots are at, or slightly above the surface of the soil. Did you ever remove the tree from the direct sun light, or heat the growth medium to 64 - 70F (18 - 21C)? Have you actually taken the temperature of the root zone? However, now the tree has been indoors for some time. The critical time to know what the root temperature is, is when you bring the tree from the outside into a warn house and set the tree directly in front of a south window. Many people think they are doing the tree a favor by leaving it outside as long as possible before bringing the tree indoors. When one does leave a citrus tree outside, the growing medium needs to be warmed before bringing the tree inside, or the tree needs to be placed in lower light until the roots warm up, before setting the foliage in the direct sun of a southern window where the tree sets for the entire day, --day after day. - Millet
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Old January 30th, 2007, 09:42 AM
CityOrange CityOrange is offline
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Re: Orange tree in danger..help..leaves falling off and branch tips brown

I also have an orange tree with its leaves falling off. Where do I get a hygrometer to test the humidity? Also, the tree doesn't slide very easily out of its clay container, is this a sign of root rot? Mostly when the leaves drop off the stems stay green, there are a few brown ones. Should I clip off the brown stems? My poor tree only has 8 leaves left so any help you can give me would be greatly appreciated.

Thank you.
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Old January 30th, 2007, 10:05 AM
skeeterbug skeeterbug is offline
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Re: Orange tree in danger..help..leaves falling off and branch tips brown

Hi CityOrange,
You need to determine why the leaves are falling off. The 2 main reasons are root rot (from too much water/compacted soil) and the cold root/sunlight combination mentioned earlier. When was the last change of potting soil? If it has been a while (4-5 yrs) I would suggest a repotting.

There are other causes, as Junglekeeper mentioned low humidity. Salt accumulation in the soil can also cause problems, but is usually associated with brown tips of leaves.

You can get a hygrometer in most department stores--they often come with a barometer and thermometer on a wooden plaque.

You can trim the brown limbs--just above the green if you want.
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Old January 30th, 2007, 10:28 AM
CityOrange CityOrange is offline
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Re: Orange tree in danger..help..leaves falling off and branch tips brown

Thank you for your fast response.

I actually just re-potted it about a month ago. I didn't know to look at the roots then, but I do remember the roots being tightly compacted together with a lot of clay packed in between them. I think the previous soil was some sort of wet sand/clay mixture.

I'll check the roots again, do the trimming, and try to find the hygrometer. Thank you for detailing it - I thought it was something I would have to stick in the dirt!

Thanks again!
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Old January 30th, 2007, 10:30 AM
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Re: Orange tree in danger..help..leaves falling off and branch tips brown

As skeeterbug pointed out hygrometers are usually found in units in combination with a thermometer. I prefer the digital units with max/min capability over the analog ones. They're also reasonably cheap (~$20-30 CAD).
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Old January 30th, 2007, 12:43 PM
Millet Millet is offline
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Re: Orange tree in danger..help..leaves falling off and branch tips brown

In actuality, over watering, or even flooding does not kill the trees roots. What actually is taking place, is that the water has displaced the soil oxygen. It is the deficiency of oxygen that kills the roots. Citrus roots, like people, require large amounts of oxygen. When a person drowns, it is actually not the water that kills the person, it is the fact that the person cannot breath, because the water has displaced all the oxygen in the lungs -- again the lack of oxygen. This same process happens when the growth medium becomes compacted. The oxygen is squeezed out of the soil. When the growth medium become compacted, ether from time and repeated irrigation, or because the wrong ingredients were used, that did not allow for a good soil porosity, it only takes minimal water levels to remove what oxygen remains in the root zone. Roots take in oxygen and release carbon dioxide, which is the opposite of the leaves. Therefore, two means of the root's demise occurs, 1) no oxygen, 2) and a toxicity from raised carbon dioxide levels in the soil, due to the fact that the carbon dioxide cannot dissipate. I rather doubt the problem is from low humidity, as you live in Philadelphia, an area where the natural humidly is surly sufficient. Citrus generally appreciates raised levels of humidity, but also do well in areas with extremely low humidity levels like Arizona and the Californian deserts. Citrus roots are never MOSTLY all white. Only the root tips, and olny on roots with current/recent growth are white. Healthy roots are a light tan color, and dead roots are a dark brown. Roots that have died from root rot are a dark mushy brown. Lastly, there is probably over a dozen different reasons why your trees are experiencing leaf drop. Insufficient soil temperature, in relation to foliage daytime temperature is the most common reason. - Millet

Last edited by Millet; January 31st, 2007 at 06:52 PM.
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Old January 31st, 2007, 10:28 AM
CityOrange CityOrange is offline
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Re: Orange tree in danger..help..leaves falling off and branch tips brown

Thank you all for such helpful responses!

I just pulled my tree out of the pot. The roots look like Millet described - mostly tan with white at the ends. I haven't seen any dark mushy roots yet. Since my tree has been inside for several months, I don't think the foliage/soil temperature difference is a problem. Is there anyway to put oxygen into my soil in case that is the problem? When I repotted him a few months ago I used Miracle-Gro Potting Mix. I don't see any other details on the package, but was this the wrong stuff to use? If so, what should I get?
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Old January 31st, 2007, 06:20 PM
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Re: Orange tree in danger..help..leaves falling off and branch tips brown

Quote:
Originally Posted by Millet View Post
Citrus...also do well in areas with extremely low humidity levels like Arizona and the Californian deserts.
That's a valid point. I've not been able to reconcile that with what I've experienced with my indoor trees. A new thread has been started to explore one possible explanation.
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Old January 31st, 2007, 07:06 PM
Millet Millet is offline
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Re: Orange tree in danger..help..leaves falling off and branch tips brown

CityOrange, Normally two months is not enough time from the transplanting date, for the growth medium to have compacted to the point where it will cause harm to the root system. That said, potting mixes such as "Miracle-Grow" and other common retail potting mixes, contain an extraordinary high percentage of peatmoss, with a little perlite mixed in. Potting Mixes high in peatmoss are not good mixtures to plant citrus trees, or any long term plant into, because these types of mixes compact rather fast. A good mix contains at least three different ingredients all of which are different in size. I use 4 parts coconut husk chips (CHC) and 1 part peatmoss. CHC's are harder to locate, but a growth medium with ingredients easy to find that you can blend yourself, is 3 parts pine (conifer) bark, 1 part peatmoss and 1 part COARSE sand. Don't use play sand, but rather something like builders sand. - Millet
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Old February 1st, 2007, 10:46 AM
skeeterbug skeeterbug is offline
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Re: Orange tree in danger..help..leaves falling off and branch tips brown

CityOrange, you said you checked the roots and they are fine, so that rules our root rot (although like Millet said the potting material you have could lead to that if not changed). You also say that you do not think the roots are too cold, but have you actually measured the soil temp. People are often surprised at how low the soil temp is when they measure it -- especially when the pot is sitting on the floor next to a window. The soil temp needs to be in the mid 60's to supply leaves with sufficient moisture to cool when they are exposed to direct sunlight.

Skeet
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Old February 5th, 2007, 09:19 AM
CityOrange CityOrange is offline
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Re: Orange tree in danger..help..leaves falling off and branch tips brown

Hi Skeet,
No, I haven't measured the temp of the roots yet. I have a thermometer/hygrometer on order, but I'm not sure if that will actually give me the temp at the roots. I've been reading through the previous posts and there is quite a bit of info saying to heat the roots. How might I warm the roots?

Thanks again for all the help!
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Old February 5th, 2007, 12:05 PM
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Re: Orange tree in danger..help..leaves falling off and branch tips brown

Quote:
Originally Posted by CityOrange View Post
I have a thermometer/hygrometer on order, but I'm not sure if that will actually give me the temp at the roots.
You may be able to make use of the outdoor temperature probe if your unit has one. The one that I have is encased in plastic and is sufficiently protected for on the spot use in the soil.

Quote:
Originally Posted by CityOrange View Post
How might I warm the roots?
Wrap a string of incandescent Christmas lights around the container.
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Old February 5th, 2007, 05:41 PM
skeeterbug skeeterbug is offline
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Re: Orange tree in danger..help..leaves falling off and branch tips brown

I use a Chef's thermometer-- one that reads temperatures from about 20F to about 150F-- and I insert it about 3 inches into the soil about midway between the side of the pot and the trunk.

I have about 15 pots with seedlings and I use the Christmas lights like Junglekeeper mentioned. I am using the garland type small light strings (2-3 lights per inch), but I just put a single line of the lights between my rows of pots-- I get a 15 to 20F boost in soil temp. That has been just enough to keep the soil temp above 60 on the coldest nights so far.

If the soil temp falls below 60F do not expose the tree to direct sunlight-- the 60 degree temp will not hurt the tree unless it is exposed to direct sunlight.

Skeet
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