First off, let me say hello and thank you to everyone who has provided such valuable information on this forum. I’ve learned a great deal about citrus in the last week. Despite this, however, I am still mercilessly torturing my citrus, and I am in need of some advice! I apologize in advance for the length of this post, but I want to make sure I tell the entire situation.

I bought my first citrus plant (a Bearss Lime) back in June. It lasted all of two weeks thanks to a surprise hail storm in the middle of the night. So, I tried again with another Bearss Lime, which has been growing beautifully outside since late July. Well, I moved it inside at the end of September when the nighttime temperatures started dipping into the forties, and it remained happy throughout much of October.

About a week and a half ago, we had a cold snap, and the lime started dropping leaves. This is when I found this forum and read just about everything I could find on WLD. I had the pot sitting on a tile floor in the sunroom, and the soil temp was dropping to 57-58 degrees at night.
So, first, I moved it out of the South-facing sunroom and into the North-facing living room, raised it off the floor, and wrapped the pot in Christmas lights. The soil temperature toward the edges of the pot has been at 74-75 degrees and the soil at the center of the pot has been 69-70 for the last five days. Still, the leaf drop has continued at about four to five leaves per day.

Stumped, I went to the nursery where I purchased the plant to talk with their citrus expert. He is from Central Florida and seemed to be pretty knowledgeable on citrus. He said it was perfectly normal for citrus to shed their leaves this time of year, I shouldn’t panic, and in a few weeks I’ll see a new flush.

The thing is, I’m not so sure based on what I have read here. The leaves are dropping without the petiole, they’re deep green and otherwise healthy-looking, and the plant has already shed about 50% of its original foliage.

So, PLEASE HELP before I kill another one! Is this normal behavior, WLD, or something else?

I don’t believe it is root rot because I have been letting the soil dry out to about 3-4” below the surface before I water, and it was growing fine until this point. It has been out of direct sunlight, at a warm soil temperature, and at 50% to 60% relative humidity for almost a week without change, so I’m also questioning whether it is WLD. I don’t see any signs of scale, insects, or other disease I am familiar with. What am I doing wrong?

Thank you for any advice,
Clint

I don't know what part of Colorado you are living in, but if your in the Denver metro area, you can purchase many varieties of citrus from Paulino Gardens on north Broadway. The gentlemen in Florida is correct. Citrus do drop leaves at this time of year. I have 50+ citrus trees and I always pick up leaves at this time. If you keep the tree's roots around 70F give the tree enough water and proper light the tree should be fine. If the leaf drop does not stop in a week or so, and depending on the type of medium the tree is planted in, the only other source of trouble might be soil compaction (lack of root zone oxygen), but at this early point I doubt that it is the problem. - Millet (435-)

welcome to the community, clint!

first off, i wouldn't agree with the expert from nursery saying that it's normal for a lime to drop 50% of its leaf mass.
it's just the polite way of doing things (courtesy)... he cannot say that it was your fault, of course, nor will he take the responsibility in a behalf of nursery.

but let's just leave it aside in favor of the original issue. the leaf drop has been most likely caused by a sudden change of either temperature or humidity.
the most common mistake, people make when being faced with the leaf drop is desperately changing the environment of suffering citrus tree until it stops shedding leaves (heated, unheated room, south facing, north facing window, etc ...). however the problem persists, and the tree is constantly losing its leaf mass density. and everything due to tree's bootless attempts of adapting the newly created environment, each time. in most of the cases solution is rather simple, just stop moving the tree. once it gets room to adapt the new environment it'll stop dropping leaves.

why don't you just leave it go dormant, which is much easier and safer (unheated but bright room) instead of forcing it to adapt heated environment where it might lack extra light?

take care,
igor

Thank you both very much for your replies. At this point, I think I will try your advice, Igor, and stop trying to change things. I don’t really have a good place to let the plant go dormant, though. The house is obviously heated, I don’t have a greenhouse, and the garage gets very cold and dark in the middle of January!

Millet, I am up in Fort Collins. Unfortunately, I know my medium is not ideal. Following the recommendation of the nursery, I used a 50/50 mix of perlite and potting soil with a high sand content. It drains quite well but dries out quickly. I would like to eventually repot it with your CHC/Peat mixture, but I don’t want to stress the plant further right now. If it doesn’t stop in another week, should I just go ahead and repot with CHC?

Thank you both again,
Clint

Recently I have received numerous private messages from members of this forum about their trees dropping some leaves at this time .My trees are growing inside a warm greenhouse, and they drop some leaves every year about now. Concerning your potting mixture, the growth medium for a container plant should have a soil air porosity of 30 to 60 percent. This porosity should be made up of large pores and small pores. Some people believe that moving a citrus tree to a new environment causes the tree a problem, perhaps that might be so, but I have moved hundreds of citrus trees in and out over the years with out any trouble. It is certainly true that citrus favor a humid environment, but many hundreds of thousands of citrus tree also grow well in the dry deserts of the world. You wrote that the growth medium of your tree was down into the 50s F. after bringing the tree indoors. I think that is what has caused this tree the problem. At temperatures at or below 55.4F, citrus roots are dormant, and cannot send any water to the tree's foliage, therefore the tree's leaves can easily over heat. . If the leaf drop stops, you can transplant your tree in the spring. Keep the container at 70F. The best to you and your tree. BTW, Fort Collins nursery used to carry citrus trees. I don't know if they still do or not. - Millet (435-)

Millet,
Thank you again, and I am sorry to have asked a question that you have no doubt answered a hundred times now. My main concern was the leaf drop wasn’t stopping after I raised the soil temps above 70, but after your reassurance, I’ll just give it a little more time.

Funny you should mention Fort Collins Nursery. That is where I purchased the lime. They seem to be carrying a fair amount of citrus these days, and the staff is always helpful. I would highly recommend them to anyone in the area.

-Clint

Thank you, Karoly.

I’ve been watching the humidity, and for right now, it has been hanging in there at ~50%. As we get deeper into winter, though, I know the humidity will drop. I might have to look into a humidifier or maybe a pan of water to keep the moisture level up.

Thanks for your insight,
Clint

I moved my tree last year from the garage to the greenhouse and it dropped all its leaves in a week. Guess it depends on how hard the shock is for the plant.

The greatest leaf drop occurs during the spring flowering period. I might be wrong but I believe this is due to ethylene which increases in plant during blossoming.
You can observe some leaf drop also when the fruits ripening.
BTW, you can make a simple experiment if you want in the same room with your citrus plants placing a basket of apple, after one-two weeks all citrus trees will defoliate.

The more common factors contributing to the early drop of citrus leaves are temperature, and soil moisture extremes, mineral nutrition problems, high wind velocity, low relative humidity, excessive root injury, insect and mite injury, and misuse of some sprays.

A lack of nutrients should result with unhealthy leaves at first or not?

Well, despite having spent the last two weeks now at a soil temp of 75 degrees, the poor Bearss is still in trouble. It is still consistently losing about four leaves every day. Following Igor’s advice, I haven’t tried to change anything this week and instead just let the tree acclimate; however, it is still not happy.

I am starting to wonder if Millet was on the right track about the soil compaction. My medium is quite sandy, and despite having perlite in it, I wonder if there is not enough air penetration. At this point, do you think it would be worth trying to repot in CHC/peat? I don’t want to keep changing things for the poor little guy, but I am more worried that something is still stressing the plant.

-Clint

Here you can read few opininons about sand!
link

I agree with Igor on humidity , I kept some citruses in low temps but high humidity and had no problem at all.