Epsom salt/MgSo4 for yellow phal leaves with unexpected "side effect"

[chrissi]

Hello, I am new to the orchid board and have a question for any growers out there that have experience with using epsom salts on phalaenopsis. About a month ago I purchased a beautiful phal which had one of its lower leaves turning yellow and looking a little shriveled (the rest of it was stunning, and I thought it might just be an old leaf, so I bought it anyway)! Anyhoo, I did some reading about yellow leaves and MgSo4/Epsom salts and decided to try it once all of the buds had bloomed and the orchid seemed to have stopped growing. After three treatments (1/2 teaspoon epsom salts in about 1 gallon of water), not only was the yellowness of the leaf completely gone and less wrinkled, each of the two flower spikes grew another 1.5 and 2 inches with new buds on them! Has anyone had this experience before? Does anyone have advice on how to use MgSo4 routinely, ie. once a month, once a year, every watering, every other watering, mixed with usual fertilizer (if watering weakly weekly), in stead of usual fertilizer, etc.? Two of the treatments I gave my orchid I had dissolved 1/4 strength of the usual fertilizer which has an extremely low Mg content, prior to adding the epsom salts and there was no precipitation issues. Thanks.

[Vanda lover]

I use epsom salts occasionally, perhaps a couple of times a summer, but I also wonder whether anyone uses it more often. I know it is great in the garden for producing more bloom on tomatoes and Rhododendrons like it. I have also used it to get African violets to bloom.

[shushu45]

I would like to know more too.

[tucker85]

Congratulations on diagnosing and treating your problem. It's always satisfying when something we do actually works. I've always heard that phals appreciate extra magnesium (Epsom salt). I used Epsom salt on all my orchids for several years but I now use a calcium/magnesium supplement. Many of my phals do the same thing as yours and put out new growth and more buds after the initial blooming. I use magnesium twice a month. I sometimes add it to my fertilizer but I like to give it separately, on a different day, if I have enough time. When I used Epsom salt I used one teaspoon per gallon twice a month but I have friends that use up to a tablespoon (3 teaspoons) per gallon. In my mind I'm just trying to prevent deficiencies so I don't need large doses. Since you had results with the dose you gave, maybe you should stick with that dose and give it a couple times a month. It's still possible to occasionally have a lower leaf turn yellow though. Good luck.

[Vanda lover]

one tablespoon per gallon is the amount I use also

[HighSeas]

I supplement with Mg also. I think it does make a world of difference in the condition of my plants. I've noticed that my phals bloom spikes last longer and go on and on and on. I have about 6 or seven that have been in bloom for between 7 and 9 months...covered in many beautiful blooms and branching now. They get a second wind and really put on a show. As a result, I rarely if ever cut a spike when it's down to only three or four active blooms.

I have to say that I do worry about what kind of stress this may be putting on my plant, to be in bloom for so long. One in particular has two spikes which are each 4 and 5 feet long respectively. And still going strong going on 10 months.

The only other thing I've changed is using RO water so in all honestly, I'm not sure which "change" made the difference. I used Epsom salts at 1 tsp per gallon and then changed to MgPro.

[Vanda lover]

My phal spikes tend to be on the short side. It must be time to give them so epsom salts again.

[RHF]

Magnesium is the essential mineral component of chlorophyll - like iron in our hemoglobin. Calcium is also a critical plant nutrient, regulates a bunch of stuff. I use Epson salt once every three months (1 tbs per gallon) and top dress pots with oyster shell (chicken grit) every time I repot.

[ALToronto]

It's not a good idea to unbalance the Cal-Mag ratio. If you're supplementing with magnesium, you should also increase calcium, so that the Ca:Mg ratio is 2:1 or more.

A single large dose of Epsom Salts is ok to mitigate a deficiency, but longterm supplementation needs to include calcium.

[shushu45]

Originally Posted by ALToronto

It's not a good idea to unbalance the Cal-Mag ratio. If you're supplementing with magnesium, you should also increase calcium, so that the Ca:Mg ratio is 2:1 or more.

A single large dose of Epsom Salts is ok to mitigate a deficiency, but longterm supplementation needs to include calcium.

What would be a good source of Ca??