Meyer Lemon, green leaves falling

Help! We bought a Meyer Lemon tree back in February 2006. We keep it indoors in a pretty good size pot. Over the first few months, it bloomed wonderfully and fruit started to appear in great numbers. At the first of May we found a couple branches with a small infestation of spider-mites. As a solution, I sprayed the whole plant with a recommended organic floral-based insecticide. The spider-mite problem soon disappeared. Around mid-May, we had two things happen. One, we had about four days worth of unusually high temps for this area, highs at around 95 F and no A/C. The Plant is upstairs and who knows how hot it got indoors here. Two, we noticed about this same time a few leaves started falling. The odd part about this, is that those leaves that fell looked perfectly healthy, big and green. No sign of yellowing or dryness whatsoever. As time passes, it seems leaves are falling in greater numbers. As to the fruit, I noticed about the same time the leaves started falling, the lemons seemed to stop growing as well. Right now we have about eight lemons the size of a thumb. Before the leaves started falling, the fruit was growing at a pretty good rate.

Is this normal for a tree starting to grow fruit? Any ideas on how to mitigate this if it is not normal?
If more information is needed to provide an idea of the cause, let us know. We'll be glad to give more specifics.

Any help or thoughts would be greatly appreciated!!!!

First of all, I'd like to congratulate you on getting fruit. It's unusual to get citrus to fruit indoors. Do you intend to keep the tree indoors? Citrus trees need sunlight all day to flourish. Consider summering it outdoors.

Canby just may be within the citrus borderline regions of Oregon. If so, hardy citrus, satsuma mandarins and kumquats, will grow in the ground in protected areas (microclimates). Unfortunately, lemons are among the least cold tolerant. How long it stays cold also affects a citrus tree.

Eventually, the size of the plant and pot may make it difficult to move in and out of the house. If you have a south facing porch or large overhangs, you might be able to provide protection for most of the winter. Covering the potted tree with mini Christmas lights and covering the whole thing with a temporary plastic greenhouse would also work. I found an article, by the University of Oregon's Extension Service, that may be helpful. Also talk with your county extension agent for other suggestions.
http://extension.oregonstate.edu/news/story.php?S_No=4&storyType=garden

Leaf and fruit drop can be caused by too much or too little water, high temperature, low humidity, nutrient deficiencies, pests, fungal diseases and wind damage. In your case it was probably the heat, but I see what may be the beginnings of nutrient deficiency as well. Citrus generally self thin fruit it can't support.

Bettydee,
Thank you for the reply and the reference to the article. We plan on keeping the tree indoors during the winter months, and it will soon be going out doors on a south porch, but staying in the pot. As to the leaves falling, I too was thinking it was the heat, but now we are in June, weeks later, and the leaves keep falling. Is there something I can do to stop this or am I destined to end up with a leafless tree? I will be getting more nutrients today for it as well.

If the leaves are still dropping off, then examine the other reasons for leaf loss. Citrus need moist, but not soggy, soil. Water when the top 2" or 3" of soil feel dry. The rest of the rootball should still feel moist. Don't let water stand in the saucer. Overwatering or letting the soil dry out too much are also common reasons for leaf loss. Consider the way you have been watering. Try increasing the humidity.

I would check the roots to rule out root rot. If roots are OK, I would flush the soil.

Meyers seem to do this more than lots of other citrus. SB

both of you thank you for your replies. stressbaby, what is the best method for me to diagnose root rot? I believe I have seen this once before in my first days as an aspiring green-thumb where I didn't provide sufficient draining for a Majesty palm. But I was only able to discern my problem after removing the dead plant.

I'm beginning to wonder if this might be a problem as I think I may have a problem with over watering.

Thank you again for your time and help.

Jake

Hi Jake. The only way I know of to check for root rot is to pull the tree out of the pot.

Mushy, dark roots: bad
Firm, white-tipped roots: good

For me is is always a little nerve wracking to pull the plant out of the pot. But if you have root rot, you'll be glad to know and to be able to correct it. If you don't have it, you haven't harmed the plant any.

If you have it, post back, there are remedies. I got four mail order citrus last fall and could not pot them up right away. Three of four had root rot within a week. They got first aid and all are doing OK now. But the only way to know is to just examine the roots.

What is your growing medium?

SB

SB,

Thanks for the reply again. I think I'm going to wait on pulling the plant. Since posting and finally moving outside for the summer, leaf-dropping has pretty much ceased. Now it's a wait and see if it stays the same, returns to it's shedding of leaves, or if it starts growing anew.

As to the growing medium, if I understand the question correctly, I'm just using Miracle-Gro potting soil. Nothing fancy. Any recommended additions for Meyer Lemons?

Thank you again,

Jake

Just to add to everyone else - My citrus typically drop their leaves in the spring & grow new ones. It's a bit unnerving, but every year, just about the time the trees move to their new outside summer home, all the leaves simply drop off to make way for the new leaves. Sometimes I have a few leaves left, somtimes I have a bare tree. But I understand this is normal for citrus since they don't do the usual winter-time shed of deciduous trees.

You can tell the difference between normal springtime leaf drop and pathologic leaf drop by whether or not the petiole drops with the leaf. If the petiole drops with the leaf, that's normal. If the leaf falls without the petiole, with the petiole attached to the branch, that is pathologic.

I grow my citrus in coconut husk chips upon the recommendation of several other hobby citrus enthusiasts. My "recipe" is described in detail on a thread on the greenhouse forum.

SB