I am no Citrus expert by any means, I have only a couple of potted citrus myself...but I've had them for 3-4 years. Can I ask you what type of fertilizer you used? I know that when I first bought mine, I added some fertilizer(citrus), and something similar(but not exactly) like that happened. When I read the fertilizer...I found out it wasn't recommended for Potted Citrus...only for inground. Basically some of the leaves on mine got fertilizer burn. Not saying that is what happened to yours, just saying it "might" be a possible reason for the brown spots. Now I used a slow release...there are several out there for Citrus...Osmocote or Dynamite...both of these will not burn and will release the fertilizer slowly and is recommended for Potted Plants. "If" that is the cause...the next time you need to water it, flush it out with extra water till it comes out the bottom... but Don't do it unless it needs watering. Hopefully it will flush out the excess fertilizer... Maybe someone that is more experienced will be able to diagnose it? Good luck!

Looks like spider mites; you won't see them without a good magnifying glass. A good wash outside or in the shower will go a long way to getting rid of them. My advice... lose the fertilizer spikes and replace with a good soluble citrus fertilizer applied 3-4 times per year according to the label. Your tree looks to be a little underfed; and unhealthy trees are more susceptible to spider mites. I would also get a good foliar fert. and give your tree an application of that about every 15 days; I like Bayer Bayfolan Forte; lots of container growers here use Foliage Pro... there are others. Your tree looks a bit leggy; I am guessing it gets less light than it would like.

Sean, as long as your Vigoro has micronutrients, that's fine, but I would also hit it with a foliar application of Grow More Citrus Growers Blend. It is something you want in your "citrus arsenal" here in S. California. With all the heavy, cold rains we've experienced in the last 2 years, you're going to run into the same issue I have with citrus in the ground (my soil is mainly DG here in N. San Diego county near the coast): a leaching of micronutrients, especially magnesium. So, start with the Vigoro, but do make a foliar app with some micronutrients. You'll see the difference, promise :-) And Tim's right, no pruning for now. Wait until you obviously need to do some MINOR shaping. Remember, with citrus, pruning equals no fruit. Citrus produce fruit at the tips of their branches, so you're cutting off your next fruit crop when your prune! And Tim's advice about removing suckers is right on. Just break them off if they're soft. If they've hardened off, trim close to the rootstock. Our water isn't too alkaline here in San Diego county - about 7 to 7.6. Fine for citrus. But, for your little guy, acidifying the water with some vinegar and pouring it over the fertilizer may help prevent the micronutrients from getting locked out due to the alkalinity. You guy needs a bit of a rescue. Tim's advice is good. Once recovered, you probably won't need to acidify your water. You can also achieve this with your foliar application - acidifying the water you use to dissolve your Growers Blend in. When you pick up your moisture meter, pick up a decent pH meter (don't buy the cheapest one). It's worth having these in your gardening tools. I've had both my moisture meter and my pH meter for many years. Great tools to have! Patty S.

It's not "semantics", it is simply a wrong use of terminology, John. There is no chemical reaction going on, or excretion of some chemical or poison, causing graft failure. So for me, using the word "poison" isn't really descriptive of what is happening. Sorry, I have a science background, and I think I provided a pretty clear explanation, John. Steve, the Meyer lemon (or other incompatible cultivars) does not excrete something that kills the rootstock. It is just an inability to make that cellular connection well enough to support the transport of nutrients up through the rootstock and to the scion cultivar. More an "apples and oranges" analogy, since John is fond of analogies. Or, square hole in a round peg. There is basic incompatibilities between several cultivars and trifoliate rootstocks, Meyer being just one. If I have a chance to snap a photo of my container Chironja orangelo, I'll post it to show a scion/rootstock graft issue. I didn't want folks new to citrus to think that a citrus scion had the ability to poison the rootstock, definitely not what's happening at the graft. Patty S.