1/4 teaspoon in half a gallon of water. Repeat in a month. Still use extra Magnesium; Epsom Salt is also known as Bitter Salt, and is usually available in pharmacies, for foot soaking.
It may also be beneficial to pull the pebble mulch back a couple of inches from the trunk.
Use granular fertilizer with at least 10% Potassium.
I was able to acquire 2lb of Magnesium Sulfate, and I already have some Potassium Sulfate. I hope the Sulphate in both products will be enough to substitue the elemental Sulphur since I cannot find it here. I'm unable to see any thrips on the leaves, but I've had multiple symptoms of micro deficiencies in several seedlings. (Pale leaves, stunted growth, leaf deformation...) The colder temperatures seem to trigger extreme deficiencies. For some reason, I was wrongly under the impression that these plants would just stop doing anything during Nov to Feb, so won't need any food.
My collection
:
Magnesium Sulfate
Potassium Sulfate
Diammonium phosphate
12-5-20+2CaO+2MgO 2M Slow release
https://icl-sf.com/uk-en/products/turf_amenity/proturf-12-5-20-2cao-2mgo/20-20-20 + TE Foliar
https://www.atlanticaagricola.com/en/fertilizantes-foliaresy-liquidos/plantifol-20-20-2016-11-10+2MgO+TE 8M Slow release
https://icl-sf.com/ie-en/products/ornamental_horticulture/8748-osmocote-pro-8-9m/Copper
Brexil Multi
https://s3-us-west-1.amazonaws.com/www.agrian.com/pdfs/Brexil_Multi_Label1k.pdfSequestrene 138
Summers here are hot, and city water is above 3gr/L. I don't have access to mulch, so I just cover the sand with compost to try to keep as much moisture during the heat, since my access to stored rain water is limited. I put around half a cup of 8M 16-11-10 osmocote pro in the summer and the same amount of 2M 12-5-20 10 weeks ago so it should be all gone.
Here is how it looks after I pulled away the layers of compost, you may see some of 8M osmocote left:
Here an other seedling with what seems to be the same issue just developing, it's driving me crazy.
An other that I think might end up doing the same, those seedlings don't get any water but rain/collected rain, so unless it's fertilizer salt, I would rule out the irrigation water salt.
I will be adding 1/2 teaspoon/gallon of Brexil Multi, I was wondering about the dosage of Mg and K Sulfates please. the seedlings are about 10" tall.
Thank you.