“I have been using Epsom Salts on my plants and I have not noticed any difference, is there really any benefit to applying it?” – Kathy T.
There is some controversy over Epsom Salts as there is very little scientific evidence to suggest their application as a supplement is of any significant benefit, but speak to someone who uses them on a regular basis and they will swear they are worth their weight in gold. I have been using Epsom salts as apart of my feeding program for 20 years now and the results in my opinion have been spectacular!
Epsom salt is natural mineral, which has been used for hundreds of years in the agricultural and horticultural industry. Epsom salt is basically hydrated magnesium sulfate. Magnesium is critical for seed germination and the production of chlorophyll, which in turn helps strengthen cell walls and improves a plants ability to absorb nitrogen, phosphorus, and sulfur. Sulfur on the other hand is critical in the production of vitamins, amino acids and enzymes and is the compound which gives vegetables such as broccoli and onions their flavor. In North America, it is very rare to find a sulphur deficiency in plants so the application of epsom salts is more for the magnesium than anything else. Depending on what you grow, magnesium requirements will vary, but plants such as tomatoes, peppers and roses do appreciate more magnesium to produce the best yields. Sadly, most plants do not show any sign of magnesium deficiency until it is really severe, and some of the most common symptoms include the yellowing of the leaves between veins (chlorosis), leaf curling, stunted growth and even fruits that are not sweet or lack flavor. Please keep in mind some of these symptoms may also be synonymous with other deficiencies which is why it is so important to ensure your feeding program is well rounded to include all the essential nutrients as well as the equally essential micro-nutrients. Epsom salt should not be considered as a whole fertilizer and rather thought of as a supplement, applying it alone will not provide your plants with all the nutrition they require.
So what what should Epsom Salts be considered for for, it is so much more that a foot soak, here are some of our favorite uses from Epsom Salts. Please remember it should be classified as a supplement, not a fertilizer replacement.
Seed Germination – Add some Epsom salt to your seedling mix before planting to give your seed a great boost. Strong cell walls from the magnesium mean stronger, happier seedlings.
Transplant Shock – We have all seen how a plant can wilt when repotted or moved from one location to another. An application of Epsom salts will help the injured roots recover faster. It is recommended you apply this as a root soak and do not mix the epsom salts into the soil, the roots are already in shock, you don’t want to possibly burn them and add any more undue stress. if you want to take this a step further, soak the plant you are about to transplant in an Epsom salt bath (1/2 cup Epsom salts in 1 Gallon of water) a few hours before planting, this is a great trick if you are transplanting really fussy plants, but I would strongly recommend you test it on one plant first.
Increased Nutrient Intake – As mentioned earlier, the magnesium helps the plants roots to absorb other vital nutrients. most commercially available fertilizers already contain magnesium to assist, but if you use organic material to fertilize, epsom salts is a great solution to increasing a plants capacity to take up all that natural goodness.
Greener Leaves – If your plants are suffering from a magnesium deficiency, a foliar spray and root soak is a great way to green your plants up relatively quickly. As many nutrient deficiencies do result in yellowing leaves, there is a good chance you may see no difference. I personally think the application of the Epsom salts is a great way to gauge if the underlying issue is more severe which may require a soil test if you do not see any improvement.
Curling leaves – Again this is a symptom for numerous deficiencies and the application of Epsom salts will likely not repair the existing damage, but rather prevent any new leaves from suffering the same fate. A Boron deficiency with is a trace element can also produce curled and deformed leaves so be sure you are applying those micro nutrients!
Roses – Some growers swear that by applying Epsom salts on a regular basis their plants produce more canes and produce darker foliage. What little research has been done would indicate the foliar spraying is more beneficial than soil application.
Sweet Lemons – Okay, now that I have your attention, when a plant produces fruit, its the equivalency of a woman giving birth…… its a really taxing process!Applying Epsom salts will boost chlorophyll levels in plant cells which will result in more energy being available to your plants. This in turn means there will be access to more sugar and who doesn’t like sweeter fruit! My father experimented on one of his lemon trees for many year applying what to me can only be considered a terrifying amount of Epsom Salts with cow manure, and the lemon tree produced more fruit than any other tree on the property. So was it sweet you ask, no that fruit was still sour, but compared to the other trees there was definitely less puckering going on!
Tasty Tomatoes – Modern Tomatoes have been bred to produce massive fruits and yields when compared to the size of the plants. This also goes hand in hand with the likelihood that the plants will suffer from a magnesium and calcium deficiency. Commercial tomato fertilizer will contain this much needed calcium but the calcium with compete with the magnesium to be absorbed. Foliar feeding is the best way to overcome this problem and an epsom salt foliar spray should be applied weekly or biweekly at the rate of 2 tablespoons per gallon of water. I personally prefer biweekly but that is based on my own growing conditions.
Lawn & Grass – Who doesn’t like greener grass! Epsom salt can help grass with a healthier and greener look, and assist grass roots to grow stronger to withstand effects from the environment. For every 1250 square feet of grass apply 3 pounds with a spreader, or dilute in water and apply with a sprayer.
If your soil has a large magnesium deficiency you should not reply on Epsom salts alone to rectify the situation.
Confusing Magnesium with Manganese. I cannot tell you how many articles I have seen online that confuses these two nutrients, and what makes it even worse is the deficiency of both can cause the yellowing of leaves between the veins of the leaf, a process called chlorosis. Magnesium is mobile, and will often show up as a deficiency in a plant by causing chlorosis to the older leaves. Manganese is not so mobile, and any chlorosis due to a manganese deficiency will show on the new leaves. One of the biggest misconceptions is Epsom salts will help with Palm Frizzle Top (New leaves look disheveled and yellow) or the yellowing of new cycad leaves, but this is a manganese deficiency not magnesium. The best way to prevent this is to never give it a chance to begin with by faithfully following a good feeding program. Epsom salts will help with the absorption of the manganese to some extent, but it is not the cure.
With every passing year it would seem more attention is being made to epsom salts and understanding how it works, what aids it and what blocks it completely. hopefully in years to come, we will have a better understanding of just how it works.