Magnesium deficiency possibly the (Christmas-tree pattern of dark vein/lighter leaf is typical). Maybe instead of supplementing onsie-twosie with this and that, go for a full-spectrum fertilizer like Osmocote Plus or DynaGrow Foliage Pro.

edit: also, what's the soil? I can't see it well in your pic, but the very edge looks dark and loamy. Ruh-roh. Is it too wet?

Almost no pests cause dropping of leaves. It's almost always a cultivation issue.

I agree with limeinqueens, find a good citrus food and stick with it, following the label instructions. The two she recommends are very, very good for container citrus.

Most leaf drop occurs because of two things; uneven watering and/or change of light conditions. If you let it dry out too much to the point of wilting, then water again the plant will often drop leaves even when water conditions get better. From the plants point of view those wilted leaves are damaged so as long as it's now getting enough water it figures it will get rid of the damaged leaves and grow better ones. But if you then let it dry out again after it grows more leaves, and then water again...well the cycle starts over. And this will deplete the nutrients as the tree uses more than normal to grow those darn leaves again. So...Don't under or over water.

And follow limeinqueens advice and get better fertilizer. Kelp and Iron tone are organic type fertilizers and are for in-ground trees. Don't use them in a container. They rely on soil microbes to work and container soil has practically none. Use the synthetic fertilizer, not organic, in containers when you use soil-less container mixes, which is pretty much 99% of all container mixes.

Y'all are amazing! OK as for the soil mix it is like a quarter Pete Moss then Cedarbark and cactus/citrus soil.

It probably looks dark because it was watering day. Any suggestions on what I should do to modify the soil? It was repotted about three months ago. I can do it again and completely change out the soil. It also has some perlite in the bottom.

That picture was taken Monday. As of last night, I don't have leaves. I am attaching a picture from last night since I'm not home right now. Btw, my profile picture is the Meyer Lemon just two weeks ago! So it's changing drastically.

Thanks again!

Your soil doesn't sound like the worst or anything but lemons are really prone to root rot and like an airy, porous mix. A lot of people here use a mix called "5-1-1"

5 parts small bark chips (in the US the best product is actually sold as reptile bedding, called Reptibark, basically they're about 1/2" across, sorry my metric skills are lacking, about 1.25cm?)

1 part Peat moss (you already have some!)

1 part Perlite (coarse perlite, if you can find it)

soak the bark chips overnight before mixing it up. This older thread has pictures of what the mix looks like:

http://forums.gardenweb.com/discussions/1835739/my-new-tree-a-journey

Okay, I can definitely change up the potting mix!!

Does anyone use liquid fertilizer? What are your tactics/ thoughts? I have only used the granulate fertilizer on my other trees and only four times a year, but I hear of people using liquid fertilizer like once a week. Thoughts? Will switching my fertilizing option help revive this little guy?

I suggest when you re-pot it that you get some fungal inoculant on the roots. Here is a small package that will work - don't worry that it says it's for roses: http://amzn.to/1Km95Kd

Also, I have found that supplementing my Dyna-Gro Foliago Pro 9-3-6 with the same company's Pro-TeKt has made a huge difference for my container citrus.

Just be sure if you go that route to FIRST add water to the pro-tekt, and then after your watering can (or whatever) is 80% full, add the Foliage Pro - otherwise it will coagulate and not be effective.

OK friends!

Better draining soil (and pot)

Thanks. I just drained it, and removed damaged roots. I applied foliage pro.

Reice, I don't like the way the mix sounds that you made and I think your trees will tell you the same in a short period of time...

Limeinqueens is right..You need to make a very porous mix as soon as possible..Depending on where you live or what's available, use the least amount of peat you can handle..Rather, use more bark and perlite..

If you don't have access to making the 5.1.1 mix or anything close to it, you need to find a way to make good use of the perlite since that is the main thing to keep your soil mix open if you are using anything with fine particles such as peat....Where do you live????? Is ther a need for so much peat?

I would stop with the Kelp and other organics to give your tree it's nutritional needs and only use those as a suppliment..I would get a good all purpose fertilizer with all the micro's and macro's availabel, including Ca and do that as soon as possible..If there is a fertilizer out ther not providing Ca, then I would find a way to suppliment that...

Whe you used those cedar chips and made your own soil mix, did you use lime in it also?

When fresh, wood mulches can add acid to the soil. While it is usually a minimal amount, if the soil already has a low pH level, using cedar mulch could create a problem. If you still want to use the product, allow it to compost for a year or two or add lime or wood ash to your beds before planting and mulching. This is not usually a problem when the cedar only rests above the ground. I think cedar actually starts at a pH of 4.0 - 5.5..I think way too low for most plantings except blueberries...

Garden (dolomitic) lime adds the secondary macro-nutrients Ca and Mg in a favorable ratio. Both are extremely important to plant health and growth. It also raises pH to more favorable levels in soils with a low starting pH.

'cedar in potting mix' and found the question was asked/answered on the Pepper Forum here at GWeb. The summary says possible chemicals in the cedar would inhibit root growth and inhibit nitrogen fixation. I did not read the whole thing though.

Here is a link that might be useful: cedar in potting mix

Thanks for the advise!

After taking it out and finding now the roots looked, and seeing how overly saturated it was with the way the soil held on for dear life to the plant, I too hate that mixture! I repotted yesterday and used maybe 1/6 peat moss. I used bark and perlite as well as a very coarse soil mix. It is very light and airy now. I will probably need to check my other trees just in case and change them up, too. The other five are very heathy, but they could be hiding problems for now. I wouldn't want that mixture they are in to clog them up in winter when the sun won't help dry it out. The way the soils stuck was very surprising seeing as I only water every 8-10 days. :( I live in Oklahoma, btw.

Yes, I agree..You have to always remember this..ok?

That the MORE OFTEN you water your plants, the healthier they are. Every time you water, you wish oxygen into the root zone and fertilizer salts right past the roots..That is why many here will only abide by mixes that force them to water more often without having to worry about root rot. That is why porous mixes are so important for citrus)

Should I be watering as frequently in the winter as well?

IT all depends on sunlight, how many roots are in the pot, pot size and of course the mix you use...But what I can tell you is that if you use a porous mix, you will water much more frequently even in winter than the finer particle mixes..)

Sounds good. My mixture was definitely too heavy last winter then. I rarely watered. Same for the spring. I hadn't yet taken them out of the greenhouse, but we got an unusual amount of rain and the greenhouse flooded. Literally had a two feet of standing water, and it took almost three weeks for the trees to dry out.

Hey friends.

How long should it take before I see the beginnings of new leaves? How long can the tree survive without a single leaf? I'm worried that it's dead now. I've never had one lose all leaves. yikes.

Give it some time. I got this almost dead tree and it took a month or more to get these tiny leaves. Also, don't kill it with excessive water and/or nutrition.

R, that depends on how much light, fertilizer and the temps you privide for it..For some in very good climate areas condusive to Citrus growing, it could take just a few days to a few weeks..For someone like me, it could take months, some time years to get back up and running perfectly, even a little bit.

Growing citrus with such a short window of perfect weather and light is a true challenge when you are dealing with problem trees...Except of course if you have a nice greenhouse in full sun..)

Thank you so much! Should I do any cutting? The stems where there were leaves have started hardening and turning brown. Should I cut back into the green?

I would..Clean it up, shape it the way you want since it is all bare anyways, and let the new growth come in from there..Make sure you are giving your tree the right conditions to encourage good growth, ok?

It is critical that you make sure you do not over water it at this time...

Thanks to both of you. Here are the conditions:

Container growing in Oklahoma, averaging lows of 65, highs of 85-88 during the day. Full sun, windy, but dry heat. When the temp drops to below 60 at night, I normally start the transition to the greenhouse. This probably won't be until November.

So assuming that this particular tree stays in these current conditions until November, do I water the same or less than I would if the tree had leaves? The mix for this tree has been changed to what mikerno suggested if that helps give me advice!

R..Can you show me a now recent pic of the tree and the mix? Take some mix into 'your hand 'R', and take a close up of it if you could..How exactly did you make the mix, in other words how did you mix it up?

Watering is all dependent on how long it takes to dry out...It all depends of the temp, and sunlight even without leaves.

You have an advantage over me 'R', with longer sunny warm days and temps above 55 at night. That's great. If provided the perfect conditions in the right mix, it will bounce back faster than you think..In a very porous mix with winter moving in much later than I, I would fertilize into November!

Sure! I am on a three day business trip, but will absolutely take another picture. I watered and added foliage pro to the water last night before I left. When I changed the soil, I basically put it in a big cat litter bin and shook it up until it was mixed. Should I not have mixed it?

yes, mixing is good) In fact, it is always best to mix it damp so the peat is evenly distributed..If dry, the peat tends to not stick to the bark and run past it filling the bottom of the pot leaving the grower with a fast drying top layer and very wet bottom layer..Get it? Watch for that. Also, did you add lime?

Mike

-_- I knew there was something I was forgetting. I did not. I can still do that though right? I have not repotted the other citrus plant as they are doing just fine. This one was just my concern as it is the only one that is having major noticeable problems.