I have a potted dwarf Meyers Lemon tree that is just not doing well. It is about 3 years old, and has had periods of good growth but seems to fall into periods of "sickness" too. The symptoms are that new growth starts and does OK for a while, then the growth halts and leaves yellow with brown areas on the some edges (see pics). After a while the leaves fall off, and then the cycle resumes. There are new leaf growths starting as this is happening, FWIW. What I've tried is: re potting (was in Miracle grow potting mix, switch to 70% Perlite 30% compost). Been using a iron/trace mineral supplement and some Epsom salts, as the yellowing looked like it might be Mg deficiency. Plus Miracle grow soluable fertilizer bi-monthly. These things seem to help for a while, but not for long. I am at a loss for what else it could be, fungus? some critters eating the roots? Thoughts, suggestions? BTW, I have three other citrus trees all growing in the same area and conditions as this one, which are doing pretty well and not showing the same symptoms. TIA
The problem looks to have been caused by a toxic level of soluble salts in the root system. When was the last time you flushed out the container with clean clear water? A containerized citrus tree should have its growth medium flushed out three times a year. When flushing the container, use clean clear water in the amount of 4 times the volume of the container. The symptoms shown by your tree are NOT a magnesium deficiency. When one does not know what a tree's problem is, and in an effort to possibly correct the situation, one starts to add this or that, normally the problem becomes worse. I also do not care much for the growth medium that you have the tree growing in. The first thing you need to do is flush out the container. The best to this tree. - Millet (1,406-)
Thanks Millet. To answer your question, I have never flushed the pots with fresh water, on this lemon nor the other citrus trees I've been growing indoors; this is the first I've heard of it. However I would have thought that repotting the tree a couple of months ago with new soil would have had the same effect, no? I will give flushing a try, though. Our water is from a well and is somewhat hard normally, and with the drought lately has become noticeably harder. White deposits building up very fast on pots and all. In fact I recently switched to Brita filtered water for all my plant watering (and drinking). So the salt accumulation certainly is a very real possibility. But it does seem odd that it is effecting this lemon but not the other three potted citrus. I did not think I was blindly guessing about the Mg deficiency. I searched the web and found several sites with pics of citrus leaves with that problem; and I thought the leaf yellowing here looked very much like those pics. However since the Epsom salts do not clear up the problem, you are no doubt right that it isn't what's going on here. One other possibility, that I thought was cured but maybe not: all my citrus were in a greenhouse 1+ years ago that had a serious infestation of pill bugs. These little critters can live in pots eating the roots (and leaves) of the plants. I did notice a few (3 to be exact) pill bugs in the dirt of this struggling Meyers Lemon when I transplanted it a couple of months ago. I removed most of the old soil, checked for more pill bugs and followed up with an insecticide that has been effective for killing them in the past. However it is certainly possible that some remain in this pot, munching on the tree roots. Could this cause these symptoms too? I'll give the flush a try. Do you think I need to use filtered water for that flush, or will regular tap (hard) water serve? And you mentioned that you don't like this soil mix I am using much. What would you recommend instead (I though the perlite/compost mix was recommended here)? And again, if I change the soil again is there any point in flushing or will the new soil be serving the same purpose?
I would repot, flushing is fine but only if you are not repotting with new medium, otherwise you may not solve your plant's ailment. Pot up this time of year. Also, as the temperature increases , promoting/stimulating growth will improve the plant's vigor.
If your water is as hard as you say, quickly leaving a white residue, in the container, then that water is not usable to use in container culture, and can EASILY be causing your tree's problems. The #1 growth medium used world wide by tree nurseries is 3 parts pine bark chips, 1 part coarse sand (concrete sand) and 2 parts peat moss. I use 4 parts Coconut Husk Chips (CHC) and 1 part peat moss. What you want to achieve is a fast draining soil that also hold sufficient water for the root system, and still give good support for the tree as it grows. - Millet (1,405-)
