Do you recall my little Algerian Mandarin that I've been trying to spur to grow with fish emulsion? That hasn't worked. It has more leaves that get dark spots on them. Then the leaf yellows and eventually falls off. There are also some deadwood areas on the tree. (My other citrus get some deadwood in the summer as well.) Feeling the soil, I think it is too dry.
First, for context, this picture shows the mature Valencia Orange on the left, near the tiny, newer Algerian Mandarin that's struggling on the right.
Along with these pictures, I brought a leaf to the nursery. After speaking with a few employees, the proposed issues are underwatering and micronutrient deficiency.
Regarding the watering, unfortunately I don't have a separate irrigation valve to devote to the longer, deep watering better suited to trees. We may figure out a way to make that happen, but for now that's not the case. This tree is pretty far from the nearest hose bib and across a driveway. Getting a hose there brings the hose past a pot of succulents and results in arms of the succulent being knocked off. And our hose storage is an old plastic pot where the hose gets wound up by hand. While the tree does get supplemental watering by hand in the summer, since it is such a hassle to get the hose to it the watering is done with a watering can and isn't a significant amount. Watering by hand has been a job my kids do on the weekends. They do it very quickly, so I know not much water is getting to the trees, although it is enough to help some little pots we have. We have the trees on drip irrigation that runs on the same valve as the nearby landscape plants. A few weeks ago, we added some emitters to each tree (going from 3 to 4 or 5), but this valve runs briefly due to the other plants on it.
To change the watering for now, I've taken over the citrus watering myself. We bought a hand crank hose reel so it is easier to put the hose away. Also, I used a shovel to widen the wells and give them better berms, hoping to be able to fill the wells with a meaningful amount of water.
Regarding the micronutrients, I fertilized three ways today.
1) I used about half a bag of chicken manure in the well and to build the berm for each tree.
2) I dosed each tree with an organic citrus tree fertilizer.
3) I added Citrus Grower's Blend to the well area of each tree. The point of this product is micronutrients.
I'll water deeply weekly for a bit, then reassess. Next time I'm targeting nutrients, I'll consider if I should add iron and/or humic acid
