Epsom Salt

[E-Jag]

A friend and I went to an absolutely outstanding show this past weekend put on by the Tampa Bay Orchid Society. I spent a little while talking with a couple who had a large display and some huge, dazzling blooms. They indicated that, in addition to weekly fertilizing, they add epsom salt to the water. Because of the crowd I wasn't able to pursue this. Does adding magnesium and sulfur make that big a difference? Assuming so, how much and how often?

E-Jag

[11Orchid126]

I add epsom salts to the fertilizer at least once a month, in addition to the magnesium that's in the fertilizer. In the winter during the dull light I only add a teaspoon to a gallon of water, and in the summer when the plants are outside and growing rapidly I add a tablespoon to a gallon of water. I don't know about sulfur.

[E-Jag]

11orchid126, thanks. I did a quick search on this and the impression I got was that magnesium sulfate is found in any decent fertilizer. Perhaps adding more is of some benefit to an orchid, or any plant. Appreciate your input, I believe I'll put mine on a monthly regimen and see what happens.

E-Jag

[Sharyn]

Exactly, what is it that the Epsom salts are suppose to do? I've read totally contrary opinions: Some feel that the addition of epsom salts several months prior to blooming increases the flower size; others totally disagree and say it doesn't have any effect.

I'll leave the scientific analysis up to those more competent in the subject, but I thought that most balanced fertilizers have sufficient nutrients for most orchids.

[E-Jag]

Hi, Sharyn - I believe you're right about most fertilizers containing magnesium and sulfur. In short, I haven't the remotest notion what, if anything, adding more is supposed to accomplish. Ergo, this thread. I suspect there may be some few aids to bigger, more colorful blooms but I don't know if this is one of them. There were some truly incredible orchids there, though.

Rick

[Sharyn]

Originally Posted by 11Orchid126

I add epsom salts to the fertilizer at least once a month

If I remember correctly, you've been growing orchids for many decades. I know there's a reason that you're using the epsom salts. Please help out the rest of us - WHY?

[Andrew]

Magnesium is the central ion in chlorophyll. As a lot of the plant's nitrogen is used in chlorophyll, a lack of magnesium can limit the ability of plants to utilise nitrogen (which is why chlorosis is a common response to both magnesium and nitrgen deficiency in plants). Most good fertilizers contain magnesium although some cheap ones don't so check the label. Additional fertilising with epsom salts should be beneficial none the less. As for sulphur most fertilizers contain plenty of it so it's not really giving the plant anything it doesn't already have.

[11Orchid126]

Yes, as Andrew says, magnesium helps a plant to utilize calcium. That's why a good fertilizer will have both. This is also true with us humans. You can take all the calcium you want, but without magnesium it may not be utilized.

[PhalPal]

I just read about this in 'Orchids' magazine, February 2008 issue, authors Renee and Marvin Gerber. The below is quoted from the article:

"We started using a fertilizer with significant calcium and magnesium added to the nitrogen, potassium and potash found in most formulas. There is a scientific basis for adding these elements. Orchids need more calcium to take up nitrogen, which is the main 'growth food' in fertilizer. However, they need additional magnesium to be able to use the calcium properly. The product we are currently using is Peter's Professional Cal-Mag. Similiar additives are found in the fertilizer developed by University of Michigan." (MSU)
They add this weekly to other fertilizers they use, i.e. super thrive, STEM (micro nutrient mix) and Dip and Grow.

My interpretation of adding epsom salts if that the usefulness to the plant is reliant on how much calcium and nitrogen is present. Magnesium is the catalyst of calcium and nitrogen absorption and needs these two ingredients as well to have any effect on the plant.

I bought a bottle of Grow-More Maxi-Cal and have yet to try it but will let all of you know if I see better results in the future.

[Bolero]

I do add Epsom Salts but only a couple of times a year, I find it greens up those aging leaves beautifully.

It does make a difference to the appearance of the plant and I recommend adding it. I only do it every 6 months but I know others that do it more often.

[articuno75]

I just started the once a week "weakly/weekly regiment of fertilizing here recently. I also started added Epsom salt to the fertilizer to see if there are any results. I have noticed the leaves being greener with only a couple of the treatments. I figured with the wormtea and adding this to the routine, I should have blooms the size of my head.

[jerrymeola]

Epsom salt unfortunately will not do anything directly to produce extra large flowers. Age and good care will do more.

Magnesium is necessary and critical in Florida where our high rains wash everything out of the soil. All good fertilizers have magnesium in Florida but northern climates may not since it is not as critical a shortage for the plant there.

I do not feel it is necessary for orchids although it certainly does not hurt them. I have used it occasionally but did not notice any significant difference. It is critical on most trees in Florida, although, a treatment every couple of years has been sufficient for me. You notice the deficiency quick when the vanes in the leaves stand out in a different shade of green from the leaf. Sprinkling Epsom salt on the ground can reverse this in a short time.

[Cynthia, Prescott, AZ]

There was a report that regular addition of magnesium to plants will make Miltonia leaves wrinkle in an accordion fashion.

[E-Jag]

Evidently, then, it may or may not have any noticeable effect but likely won't hurt. I may give it a go for awhile, see if I can imagine any difference which I will then erroneously report as cause and effect. Your replies are appreciated.

_________________
E-Jag

[FLaCo]

I know this is hard to do but use it on all but 1 plant ( a control specimen) and then you will be able to see if it makes a difference. Treat the control like every other orchid you have except refrain fro adding epsom salt to it.

I plan to do this on one of my Vanda seedlings but for SUPERThrive.