Citrus Growers Forum

Skeeter · Posted: Wed 12 Nov, 2008 3:24 pm

I have some good evidence that changes in light level are part of the cause of leaf drop. I have 4 key limes in containers, 2 have been under my sunscreen all summer, but 2 have been sitting in nearly full sun. With the recent cool weather, I moved the 2 that were in full sun under the sunscreen to prevent winter leaf drop. Today that are dozens of leave under those 2, but almost none under the 2 that have been under the sunscreen. They are all still healthy, only the older leaves are dropping from the 2 that had been in the sun, but it does show that a significant change in light level is responsible for some leaf drop--just a natural adjustment to lower light.

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Skeet

Steve · Posted: Mon 08 Dec, 2008 11:37 am

Skeeter wrote:

I have some good evidence that changes in light level are part of the cause of leaf drop. I have 4 key limes in containers, 2 have been under my sunscreen all summer, but 2 have been sitting in nearly full sun. With the recent cool weather, I moved the 2 that were in full sun under the sunscreen to prevent winter leaf drop. Today that are dozens of leave under those 2, but almost none under the 2 that have been under the sunscreen. They are all still healthy, only the older leaves are dropping from the 2 that had been in the sun, but it does show that a significant change in light level is responsible for some leaf drop--just a natural adjustment to lower light.

Well, I cannot realy agree... because I move the trees form outside in. From the cold free nature indoors, were direct sunlight is missing.
I only heat up the rootball, and I encounter no leaf drop....
So if light would be a factor, I had to encounter a hard leaf drop as your trees did....

But what I found in such circumstances: Often the trees were highly stressed in cold outside and direkt sunlight... os much abscission, a plant hormone is formed. Now you move the plant, from full sunlight to less light, which in my oppinion will reduce the stress, and the abscission now comes to count, because with higher auxin levels again, the leaves will be abscised.

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Eerh, hmm, uuuh, oooh, just guessing Wink

JoeReal · Posted: Mon 08 Dec, 2008 3:58 pm

It is about balance. Temperature, Light, nutrients, water and a period of acclimatization. If you don't, the trees will do it for you, automatically, and commonly happens during transitions, and so we have WLD.

bettadaze · Joined: 08 Dec 2008 Posts: 4 Location: North Carolina

I'm new here and I really like this forum, however I do have a question about my Improved Myer lemon tree. I recently moved it indoors with all it's leaves and blooms. It has now dropped 90% of it's leave and all it's fruit, what can I do to make it recover? It was in full sun and now is in a south facing window with reduced light. I've continued watering as usual. What else can I do. Question

Millet · Posted: Tue 09 Dec, 2008 1:51 am

Welcome to the Citrus Growers Forum. We are happy to have you as a member. The question you ask is one of the most ask questions on this forum. Enter the words, "WLD" and "Winter Leaf Drop" into the search function located on this forum. You will receive a mass of information concerning the cause, and how to prevent the loss of leaves from your tree when you bring it inside. After you read, if you still have some questions, please feel free to ask. Take care and welcome. - Millet

bettadaze · Joined: 08 Dec 2008 Posts: 4 Location: North Carolina

Thank you, guess I didn't read far enough before posting. I do have one further question though, should I provide light and heat and try to regrow it before spring or let it go until it gets warmer? I've got tons of reading to do.
Thanks again, this is an awesome forum. Wink

Millet · Posted: Tue 09 Dec, 2008 11:33 pm

At the point that the tree is at now, if it was my tree, I would keep the tree's root zone at 70F, fertilize the tree at 1/2 strength, and give the tree sunlight. The other option is to let the tree go "dormant" until spring. Meyer Lemons are a finicky tree, they seem to lose their leaves easier than many other citrus varieties. - Millet

Skeeter · Posted: Wed 10 Dec, 2008 1:12 am

Steve wrote:

Skeeter wrote:

I have some good evidence that changes in light level are part of the cause of leaf drop. I have 4 key limes in containers, 2 have been under my sunscreen all summer, but 2 have been sitting in nearly full sun. With the recent cool weather, I moved the 2 that were in full sun under the sunscreen to prevent winter leaf drop. Today that are dozens of leave under those 2, but almost none under the 2 that have been under the sunscreen. They are all still healthy, only the older leaves are dropping from the 2 that had been in the sun, but it does show that a significant change in light level is responsible for some leaf drop--just a natural adjustment to lower light.

Well, I cannot realy agree... because I move the trees form outside in. From the cold free nature indoors, were direct sunlight is missing.
I only heat up the rootball, and I encounter no leaf drop....
So if light would be a factor, I had to encounter a hard leaf drop as your trees did....

But what I found in such circumstances: Often the trees were highly stressed in cold outside and direkt sunlight... os much abscission, a plant hormone is formed. Now you move the plant, from full sunlight to less light, which in my oppinion will reduce the stress, and the abscission now comes to count, because with higher auxin levels again, the leaves will be abscised.

In your case, when the plants are outside are they in full sun? That was the only difference in the 4 key limes I have. 2 were in full sun, 2 under the shade cloth--all were outside exposed to cold. The 2 that were exposed to full sun dropped a lot of leaves. There is a possibility that the roots got cold enough to cause winter leaf drop before I moved them to the shade cloth, but I don't think so--the leaves that dropped were the oldest leaves, not the ones exposed to sun.

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Skeet

Steve · Posted: Thu 11 Dec, 2008 5:38 pm

Skeeter wrote:

--the leaves that dropped were the oldest leaves, not the ones exposed to sun.

And here we meet, and I guess again on abscission accumulation...
Because I have also leaf drop in winter, but not the way like WLD, with remembers in to the leaf sheed of decidous trees, like apples or oak trees, which quickly drop their leaves ...
My trees drop their old leaves time by time... One all two or three weeks...
But I also encounter new growth... Wink

So abscission of older leaves is common after stress.

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Eerh, hmm, uuuh, oooh, just guessing Wink