Bob F wrote:
I've just been told that the curled under leaves on my italian prune
trees are caused by magnesiom deficiency and I should apply a few
pounds of epson salts under each tree.

Is the diagnosis likely to be accurate? Location is Seattle.


I don't know about leaves curling, I thought magnesium deficiency cause leaf
yellowing especially in older leaves. Can you provide a photo?

What kind of store wound I go to for a good price on 50 or 100 lb
bags of epson salt?

A few pounds per tree seems quite excessive to me, this is a trace element
not a major nutrient. If you over-do it you won't have a problem with
curling leaves 'cause you wont have any leaves at all. Another problem is
that epson salts is very soluble and unless it binds to humus or clay
colloids it will leach out quickly.

Here is another method that may be work if it is Mg deficiency. Treat some
(or all) trees with a foliar spray of epson salts, possibly repeated in a
week, if it is Mg deficiency they will recover quite quickly, that is within
weeks. For the longer term treat with dolomite which will slow release Mg
over time.

Another possibility is that the soil is very acid which tends to lock up
some minerals like Mg so liming or adding dolomite will raise the pH and
release Mg. A dye-indicator to test pH is cheap and sufficiently accurate
for gardening and can be used in many situations.

David