Hi.
I use a citrus fertilizer that doesn't contain any magnesium. So I decided I should use Epsom Salts. And also chelated iron just for prevention, because I know how unattractive citrus leaves with iron chlorosis can look. Now we don't have a product called "Epsom Salts", but we have a product that's called "magnesium sulfate". I bought a 25g package today, and it says on it "magnesium sulfate", it says it contains 17% MgO and 13.5% S, which is odd because magnesium sulfate formula would be MgSO4, and it seems like it contains magnesium oxide and sulfur. So question number one:
1) Is this actually Epsom salts?
2) What does magnesium improve in citrus trees?
3) How many times do I have to apply it? It says that I should use 25g for 10l of water and should be applied every 15-20 days.
About chelated iron:
4) How many times it should be applied? On the package it says every three weeks.
About both:
5) Is it a good idea to use both of these as sprays for leaves with smaller concentration?
6) Can I add both of these in the fertilizer solution I use every time I water? Or would they react with something that is in the fertilizer (considering the producer, for example, didn't put any magnesium in it)?

Magnesium Sulfate and Epsom Salts are the same thing. Dissolve one tablespoon of Magnesium Sulfate in one gallon (3.8l) HOT water and pour the COOLED solution over the surface of the potting soil 3 or 4 times a year. Do not use iron formulation as a foliar spray, as iron can cause toxic reaction to citrus leaves. Apply through the root system. . Personally, I would use iron only as a corrective and not as a preventative. - Millet (895-)

MgSO4 is most commonly sold in the hepta-hydrate form. (MgSO4*7H2O). Your magnesium sulfate does not contain MgO so the 17% MgO reported is an equivalency number. It means that your magnesium sulfate contains the same amount of magnesium as a substance that is 17% MgO.

Molecular mass: Mg+S+(14*H)+(11*O) = 24.3+32+(14*1)+(11*16) = 246.3

Percent MgO (equivalent): (Mg + O)/Molecular mass = (24.3+16)/246.3 = 16.4%

Percent S: S/Molecular mass = 32/246.3 = 13.0%

level TBS. - Millet (893-)

What does Mg do? Mg is the center of each chlorophyll molecule--without it the tree cannot make chlorophyll.

I also use Epsom Salt for my citrus trees , and leaves are looking more green since I have started to do this . I also have a special fertilizer for citrus from Peters but even so I add one nail (8mm/12cm to every pot I have and it works fine for me.Once he sttarted to rust he release iron in the soil

Skeeter:

Seems like I remember there are two forms, one Fe and the other with Mg at the center and the difference is they absorb at two wave lengths.
You know like different grow lights.

Not sure how Mg holds and then makes the energy transfer. Iron can make a lot of interesting energy state changes since it causes minerals to be green, blue, brown, and yellow;
but mostly we know about red blood and bluish (vienuous ] blood.

Iron can be tricky. I have burned leaves adding the sulfate to foliars. And some chelates hold too tightly to be good foliars. I'll get back later
with an old favorite multi mix. It is needed when high calcium makes citrus micro starved.

Larry

The Mg form of the molecule is chlorophyll, the identical molecule except for the central Mg replaced by a central Fe (iron) is haemaglobin, which carries oxygen in the bloodstream. Both are very large molecules with only one slight difference.

Tantanman wrote:....." I have burned leaves adding the (iron) sulfate to foliars"..........

Iron should never be used as a foliar spray on citrus trees, as it will/can burn the foliage. When applying iron additives to citrus, it should only be applied through the root system. - Millet (877-)

This is also true for Jaks(peter's) with iron chelate in it ?

I do not know about the chelated Iron you mentioned, but I would apply it to the soil, if the tree need it it will take it up.

Here is a bit more on the chemistry of iron: Iron exist in 3 states based on the number of electrons--the elemental state as the metal; Fe+2 and Fe+3. The Fe+3 form is very insoluble--we know it as rust or iron oxide and that form is essentially unavailable to plants (as is elemental iron of course). The Fe+2 form is very soluble in water, but is generally only found in reduced environments (where there is no oxygen). That form is commonly found in muck soils and wetlands--it is often found in irrigation water around here as FeS and as soon as it is exposed to air turns to rust stains on buildings.

Chelated iron is an iron molecule attached to an organic molecule that prevents it from ionizing but keeps it soluble and available to plants.

Putting iron nails in the potting sol of a container does not work. It will not supply the tree with iron. - Millet (876-)

Tomorrow il go and remove any nails from the CHC , I was hoping that this might do the trick

Well if nails in the soil doesn't work what if I put them in the water container where the water sits for 24 hours to evaporate Cl from the tap water ? Does the rusting process any good by providing iron in water for my citrus trees