Epsom salts, Magnesium sulfate, has been used by many as a supplement in an attempt to correct magnesium deficiencies. However, there is little real evidence that in the quantity commonly used there is any real benefit,
Far better is to have a good reliable soil test done and if there is a magnesium deficiency use dolomitic lime, in the appropriate amount, to correct that. Plants need both Calcium and Magnesium, in balance, to properly use both.

Here is a link that might be useful: About Epsom Salts

Lime has the inherent problem of raising the pH of the soil, so it may need to be counterbalanced. I use it in my 5:1:1 mix - about a half cup per ten?fifteen gallons.

FWIW, I have used epsom salts for peppers that start to show wavy/curly leaves. (C.chinense is bad for this.) After application new leaves no longer show the problem. So it does seem to be effective.

Dennis

Which Lime to use is determined by what the soil needs. If the soil needs Calcium then Calcitic Lime (70 to 90 percent CaCo3) is used, but if Magnesium is needed then Dolomitic Lime is used (45 percent Mg and 50 percent CaCo2).
Research shows that in the commonly used mixes, 1 cup of Epsom Salts to 1 gallon water, there is not enough Mg to make enough difference in plant growth.

Ken..........no...........you remembered correctly, especially concerning treatment of pines. It is done by foliar application, and there is university study and data supporting this modality. I used to grow several specialty crops with high requirements for magnesium in particular and would supplement the irrigation water with mag sulfate...........IE plain old epsom salts. In needle yellowing, of course it's just a guess that it's mag deficiency on your part so it bears looking deeper. You are making assumptions I think based on your soil type, and they may not be accurate. Even a soil test might not show mag deficiency and yet your pines might be suffering from it.

First off I'm not understanding your statement this pine is supposed to be yellow in winter. Is that what you meant? Mag sulfate is used to green up pines, not make them yellow.

Here is the thing......you need to determine if your soil is deficient. If tests show it is, and alkalinity is not an issue then you can proceed with liming. If your soils are already neutral or alkaline, you should not. You proceed with epsom salts. Be aware that high potassium levels in your soil or ammonium based nitrogen are antagonists to magnesium in the soil and will inhibit the plants ability to access it. So will poor drainage, over cropping, and prolonged cold into a growing season.

You will find a lot of discussion on using epsom salts in hobby magazines discouraging its use. That's because people use it indiscriminately and often when there's no reason to, assuming it's magic or something. That needed deflating and is proper. It does have legitimate and documented places in the correction of magnesium deficiency, however and is equally effective and sometimes preferable to dolomitic lime, which is most widely used in field crops and grain production as a matter of course.

The analysis of Epsom Salt indicates that it is roughly 9 percent Magnesium and 12 percent Sulfur, so if you dilute that, 1 cup of Salts to 1 gallon of water, as often recommended just how much of each are you spreading around your garden? Not very much, in reality, and not enough to do much, if any, good.

Providing a link to the a Christmas tree grower's org website, discussing the mode of application of magnesium, symptoms of deficiency, discussion of soil types IOW about everything you might want to know about plant nutrition and soils relating to pines and other conifers. It will give you rates for magnesium supplement applicationsfor foiar or combination foliar soil /application with various magnesium supplements.

Here is a link that might be useful: pines and soils

According to Dr. Chalker-Scott foliar feeding is a myth.

Here is a link that might be useful: Foliar Feeding Myths

I was fair and went to the link to read what was actually said. She did not say it was a myth. Did you read past the title which is " The Myth of Foliar Feeding" ? What she is saying is the myth is that some believe that âÂÂFertilizers sprayed on the leaves of trees and shrubs are more effective than soil applicationsâ and I did not imply that, although in some instances foliar spraying is the only way to introduce nutrients to a plant if root uptake is compromised.

Ok let's just put it this way......you can go on the internet and find material to support an agenda especially if you don't understand it or chose to only pick out a sentence of it out of context. I learned about foliar feeding when studying agriculture in university and I have used it on occasion quite successfully for over a quarter of a century, so I know it is not a myth. I rarely challenge what other people post on these forums unless I feel that they are giving out misinformation that might put someone else at a disadvantage. It isn't fair to do that and my ego isn't so big I'd feel a need to constantly correct someone. So if I offer information about something like this, it's university backed and I have the agricultural experience and training to understand it well. And if somebody can come forth with data in which I'm in error, I appreciate the correction. You might consider that an option.

From the article, "The existing research does not justify foliar fertilization of landscape plants as a general method of mineral nutrition. It can be useful for diagnosing deficiencies; for instance, spraying leaves with iron
chelate can help determine if interveinal chlorosis is from iron deficiency. It would obviously have
benefit for those landowners with landscape fruit trees that perpetually have flower or fruit disorders
associated with micronutrient deficiencies. Applying fertilizers to leaves (or the soil) without regard to
actual mineral needs wastes time and money, can injure plant roots and soil organisms, and contributes to
the increasing problem of environmental pollution."

Reguritating information isn't very helpful.

"Ok let's just put it this way......you can go on the internet and find material to support an agenda especially if you don't understand it or chose to only pick out a sentence of it out of context."

Kimmsr in a nutshell? and reread Chalker-Scotts website. You are pretty much following the paradigm that she is trying to move away from.