Fertilizer Supplements:
Is Epsom Salt Good for Orchids?

Orchid fertilization is not a complicated subject, and the more you immerse yourself in the different possibilities, the more fascinating it gets. Well, at least for me…

I once thought that fertilizing with a balanced fertilizer, 20-20-20 year-round was sufficient. Then I read about not using an orchid fertilizer with urea nitrogen in it. Then the question came up about using Epsom Salt for fertilization.

In all, is Epsom Salt good for orchids?

Epsom salt is extremely beneficial for your orchid’s maintenance and nutrition. Not only does it help with the production of chlorophyll, it aids in cell construction, proper hydration, and flushes out the orchid from salt residue. Epsom Salt will make the blooms larger and the leaves more vivid, causing no harm to your orchid.
Epsom Salt as Fertilizer for Orchids
""ORQUÍDEA PHALAENOPSIS" by Artur Luiz dos Santos is licensed under CC BY 2.0 
With the use of Epsom salt, there have been many questions about its use and exactly what it does.

This article will explain how and why Epsom Salt will make your orchid more beautiful and healthier than ever. Along with Epsom Salt, I’ve included iron and calcium in the article, since many products on the market also include those.
In this Video, I explain Epsom Salt and Orchids.

Epsom Salt? I thought adding salt was bad for the orchid.

Don’t ever, I repeat EVER add salt to your orchid. Epsom Salt is not salt. Salt from the kitchen table will destroy your orchid and burn the roots. Table salt is Sodium Chloride (NaCl) and Epsom Salt is epsomite, which broken down is magnesium (Mg), sulfur (S) and oxygen (O).

How Does Magnesium Influence Your Orchid’s Growth?

Magnesium is extremely vital for the production of chlorophyll, as is iron. If you water too heavily, magnesium will be washed out of the potting medium, so there hardly is any build-up from “overdosing” in magnesium. On the other hand, if you don’t flush your orchid, the magnesium will build up.

Magnesium is absorbed through your orchid’s roots and is transported through the entire orchid, unlike some of the other nutrients and minerals we’ll talk about below. Since magnesium flows freely through your orchid, if there is a deficiency, the orchid will try to save the newer leaves in detriment to the older leaves. The older leaves will start to turn purple or have splotches of green throughout the leaves.

A good source of Magnesium is Epsom Salt, since it is made from Magnesium Sulfate. To use Epsom Salt, you need to mix one tablespoon in a gallon of water and let it dissolve (The Epsom Salt company suggests two tablespoons, but every forum I’ve ever asked, the answers said they use only one.)

Mix it well.

Soak your orchid roots in the mixture for anywhere from 10 minutes to three hours. I was skeptical at the three hours tutorial I read, but these orchids were extremely dehydrated. This is a test you need to do and see what time is most beneficial for your orchid.

Use this solution four times a year or for every third or fourth watering. This solution will flush out your orchid, ridding it of excess fertilizer.

How Does Epsom Salt Nurture the Orchid?

Epsom salt is not exactly a salt. That is what stumped me for the longest time. It’s just a mineral composite of Magnesium and Sulfate.

According to their homepage, “Magnesium plays a number of roles in the body including regulating the activity of over 325 enzymes, reducing inflammation, helping muscle and nerve function, and helping to prevent artery hardening. Sulfates help improve the absorption of nutrients, flush toxins, and help ease migraine headaches.”
Of course, this is for humans, not orchids.

Yet numerous orchid growers have used Epsom Salt in between watering and the overall consensus was that the leaves were bigger, brighter, more luscious, and the blossoms were noticeably superior.
Moth Orchid for Beginners
"Orchid"[Mindoro, Philippines] Phalaenopsis stuartiana 'Mindoro #180501' Rchb.f., Gard. Chron., n.s., 16: 748 (1881)" by sunoochi is licensed under CC BY 2.0

What Does Iron Do For Orchids?

Iron does not aid the plant specifically, but it helps produce chlorophyll. A deficiency in iron will negatively influence in how much chlorophyll will be created, and induce what we call chlorosis. Without chlorophyll, your orchid cannot take the light it is receiving and transform that into energy.

Chlorosis is not only caused by lack of iron. If you are overwatering and have been for some time, root rot will set in, and this also causes chlorosis. Before you add more iron to your watering schedule, make sure that the roots are in good condition and capable of absorbing the iron.

What Does Calcium Do For Your Plant?

Calcium is a macro-mineral and extremely important for your orchid. Your city’s water supply usually adds a small percentage of calcium to the water already.

Calcium enters the orchid through the roots, and travels up toward the stem to where it is distributed through the xylem. This vascular system is not always fluctuating, and once the calcium stays where it needs to be, it doesn’t move throughout the plant (like our blood would move through the veins and arteries.)

Calcium has several benefits to your orchid. First, it will maintain healthy cell structure by neutralizing unwanted acidic components.

This means that once the calcium is in place, it isn’t supplied to places that don’t have it. That is why newer leaves can suffer from lack of calcium, while older leaves be fine. It’s common that you’ll first notice the calcium deficiency in orchids in newer leaves.

A sign your plant is not getting enough Calcium is when the tips of newer leaves start to turn yellow. The roots will be sprouting by the millions, but they don’t grow very long, as the lack of calcium will stunt growth.

If your pseudobulbs or leaves look smaller than the previous ones, then a good rule of thumb is that either they aren’t getting enough water or they are lacking calcium.
Orchid Scent
""紅夢香文心蘭 Oncidium Twinkle Red 'Fantasy' [香港大埔蘭花展 Taipo Orchid Show, Hong Kong]" by 阿橋花譜 KHQ Flower Guide is licensed under CC BY-SA 2.0 
You can take the yellow away from the tip of the leaves, but this will be a slow long process. As you soak your orchid in water, or as you water it, use calcium supplements. It’s best to prevent the lack of Calcium than to try to fix it later on, so maintain a regular calcium supplement as you water.
But don’t go overboard. If you use too much calcium, and do an extreme overdose in calcium fertilization, the roots will not be able to absorb any other minerals or nutrients. Phosphorus, potassium, magnesium, boron, copper, iron, and zinc will quickly become depleted from the orchid, even if they are very present in the potting medium or in the water. The roots simply won’t be able to absorb them.

Does Adding Extra Minerals and Nutrients Eliminate Fertilization?

You should not eliminate fertilization if you happen to start using another method to increase the levels of Magnesium, Iron and Calcium in your orchid. Fertilizers are made for specific purposes and just watering alone will not provide the right balance that you need.

How Much Calcium and Magnesium Does Tap Water Have?

If your orchid looks weak, pale, and just not growing well, you shouldn’t just start adding chemicals. First try to figure out what is lacking. You need to check with your city to verify how much calcium and magnesium that are already in your tap water. Too much can be just as beneficial as not enough, and in some scenarios, even worse.
This guide provided the basic minerals that could be lacking with the normal fertilization and a basic look at Epsom Salt. If you have any questions, you can download a 14-page fertilization guide here for free. or check out this article about 5 unique Fertilizer methods.

Please leave ideas, thoughts, questions, or a general thumbs up in the comment section below.
Happy Cultivating!
Signature Amanda Matthews
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10 comments on “Fertilizer Supplements: Is Epsom Salt Good for Orchids?”

    1. Hi Donna,

      Thank you for your comment. I appreciate it. 🙂

      I usually use both the fertilizer and the Epsom salt but not with every watering. I'll do an "interval watering" with Epsom Salt, one week with it, and one week without. Then the fertilizer I'll use 3 out of every 4 weeks.


  1. Amanda,
    To me you are a icon! Your advise SO helpfull and you give intelegent answers!
    Thank you so much!

  2. Just bought my first orchid and lots of great info here, so thanks for sharing! One clarification: epsom salt absolutely is a salt. There are quite a few different salts that are not sodium chloride. Salts are just ionic compounds comprised of cations (positively charged) and anions (negatively charged) forming ionic bonds that result in an electrically neutral compound because the charge of the cations and anions bonding cancel each other.

    1. Hi Mark,
      Thank you for commenting and explaining that further. 🙂 Sometimes I know what I want to say in my head but when I write it down it comes out funny. I meant to say it isn't table salt. So I'm glad you commented and explained that for other readers. I appreciate it.


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