I agree, it's probably more of a windborne issue. I used miracle grow potting soil in all my containers and I have no weeds. I'm on an 8 story balcony, so while I am definitely pulling fluffy white weed spores out of the pots I'm probably not getting the same kind of weed seeds I'd have if I were near the ground. Try mulching your containers to keep the weeds down.

doubt that it will work. you are right that the pressure will not be enough to deliver the correct concentration. Rarely do these bottles give the correct concentration normally-most of it is delivered right away resulting in both over fertilizing at first and under fertilizing in the rest of the garden.

Thanks for the reply! Unfortunately I don't live on the US and the contact form is only for customers... Today I noticed something new in one of the plants. The browning is appearing at random places in two leaves, not only starting at the edges or tips and merging like before in a "U" shape. Some brown spots are even sorrounded by healty tissue. The last things I tried where repotting the plants with a more draining soil and misting with copper (I tried other fungicides before but not based in copper). Perhaps it's some kind of fungus? There is any way to check if this is the case?

I think it is just called Howard Miracle. I have it at two locations no St. Julian rootstock. It has been very shy to bear in the first 5 years or so. I haven't really gotten a crop yet. The tree at the Home Orchard Society Arboretum in Oregon City produces fruit and they are truly outstanding. They are very large, and kind of look like nectarines on the tree. They have a unique flavor for a plum. Some say hints of pineapple.