I found an possible alternate to the almost impossible to obtain list of micronutrients I said to use above for foliar spray when leaf chlorosis is extreme as in the photos. I found a product at Home Depot that contains Iron, Magnesium, Zinc, and Manganese for use as a foliar or soil drench. The product is Chelated Citrus Nutritional by Southern Ag. I dont know if this is available on the West Coast and it is very hard to find here. The rate is one tablespoon per gallon. Always use it as a foliar in case of extreme micronutrient deficiency as in the above photos. I sprayed my trees with this stuff early last week. They were suffering from a medium case of winter chlorosis and are now showing some added color. At least one more application is indicated. The metals in this product are all chelated by a sulfonated lignin and thereby may have a somewhat similar effect as sulfate salts which I have used for years, in my home brewed mix. Since all citrus growing states are now under threat of citrus greening disease (HLB) attack it should considered good practice to keep our trees very green so any outbreak of the disease can be detected and eraticated ASAP. That is how commercial Florida growers are staying in business. Frequent inspection and spraying of the psyllids that carry this disease also figure into their programs.

I think it probably is also fertilizer burn. I would look at the N source in your fertilizer. If is is mostly from urea, this is not a good choice for container citrus. I would switch to Osmocote Plus and Dyna Gro Foliage Pro. Also, I would actually check how much water has accumulated at the bottom of the pot. You say you are checking moisture at the "root level", but if that tree's container has turned into a bath tub, and your moisture meter isn't checking all the way down, you're also dealing with root rot. Get a stick and push it down to the bottom of your container and see how wet it is down there. You say you added pine bark to the soil - how did you do that? Did you pull the tree out and completely change all the potting medium? If you just added it to the top, that won't help drainage. Pretty sure we're looking at two things - too wet and too much biuret build up from your fertilizer. Patty S.

Yes, don't bother with the spikes. Any granular fertilizer should be applied right where the irrigation water is being applied, otherwise it won't be dissolved and get to the roots. Liquid fertilizer can be applied all around the drip-line (that's where the leaves end outwards, and the area inside that). Use a Citrus fert. I agree with the folks above on the insects and watering. I'd also strongly suggest using a systemic imidocloprid, Bayer's Fruit, Citrus and Vegetable Insect Control is a good one and readily available in any good Garden Center. The LA area has the confirmed sightings of the Asian Citrus Psyllid which can carry a disease called Citrus Greening that can kill the tree and is a big threat to the citrus growers down there. So far, the A.C. Pysllid in California hasn't been infected with Citrus Greening but it's very important to stop and control the Pysilids at this point so it doesn't spread further. I wouldn't worry about the pH really. It's tough to change the soil pH for any length of time anyway especially as our water is often on the higher pH side. 7.5 isn't really that high for citrus, they can tolerate that just fine. One thing you can do which will also benefit the soil is to add a good 4-5" layer of compost around the drip-line, keep it at least 6-8" from the trunk though. It will keep the soil cool in the summer, will add humus and some nutrients to the soil and will improve the structure of the soil over time. The compost will slowly decompose and thin out over each year, this is normal and good. So you will have to add more each spring. Your trees will love you for it! I really think your yellowing is lack of food. Get a good citrus fertilizer, not spikes, and feed them according to the label instructions. Check the watering situation, (more at each time, added slower, and let dry a little between waterings), add the compost, feed them regularly, treat for the insects and by this time next year your trees should look great!

Sometimes of the tunnels aren't very prominent or there are so many that the leaf looks like a mangled brownish-white mess from underneath. Usually, I have managed stop all miner attacks by removing the afflicted leaves and disposing them far away from the plant. If you've just got the place and haven't seen these plants growing for a while, I'd suggest some pruning. Further, remove the gravel (add it back on top later), dig up an area 8 inches to 1 foot deep deep around the tree from the stem to as wide as the circumference, add lots of vermicompost, bone meal and stera meal and then water thoroughly (even if the soil is moist). Do this once and then monitor how the soil dries out. If it's hot, water thoroughly once a week (or whatever you think is fine - I don't know your climate). As a rule, if it's moist a foot deep, it's fine for the plant. As a hobbyist, I do not use chemicals on my plants, though many will tell you otherwise. I use a mix of potting soil, cocopeat, vermicompost, bone meal and stera meal to grow my citrus in pots and I have had flourishing plants. What I advised you, I implemented at a relative's place a year ago and it has yielded good results. Citrus are hardy, they will survive in bad conditions but will flourish if you provide them with natural nutrients through organic matter. That said, your plants definitely seem to require some nutrients evident from the yellowing of the leaves. Might be water deficiency too, but that is something you can remedy quickly. However, I'm not an expert. There are far more knowledgeable people around here. All the best.