Epsom Salt used on tomatoes is a water soluble chemical compound consisting of magnesium, sulfur, and oxygen. Where deficiency exists, it improves fruit production and general health of tomato plants. MgSO4 is applied on tomatoes as granules in the soil or as a liquid solution directly on the leaves. The liquid solution can also be administered in the soil around the plant.
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Where to get Epsom Salt For Tomatoes
Epsom salt is available for agricultural use as well as for spa and body care purposes. Agricultural grade Epsom Salt is used in the garden and on tomatoes. Below is a typical Epsom Salt for tomatoes available online. Espomate can also be inexpensively procured from a gardening shop.
What is Epsom Salt?
Epsom Salt is a naturally occurring mineral salt. It has the chemical molecular formula MgSO4 or MgO4S. This is to say one mole of Epsom Salt has one atom of magnesium, one atom of salt and four atoms of oxygen. Total six atoms. The compound is also known as Epsomite, Magnesium sulphate, Magnesium sulfate anhydrous or Sulfuric acid magnesium salt among over a dozen other names.
Epsom Salt is named after a historic town called Epsom. The town is located in Surrey, England some 22km south of London. A spa spring at Epsom famed for beneficial bitter saline waters is said to have been discovered by Henry Wicker, a farmer, in 1618.
Modern Epsom Salt is mostly available in granular form. Although discussed here in the context of tomatoes, Epsom Salt has a variety of other applications. It has a role in the medical field as a cardiovascular drug, a calcium channel blocker or an anesthetic, to mention but a few of its various medical applications.
Epsom Salt easily dissolves in water. It is made up of three main elements i.e. magnesium, sulfur, and oxygen. Once dissolved, it is easily absorbed by plants such as tomatoes, fruit trees and leafy greens. Tomato plants absorb Epsom Salt through the roots or the leaves.
What Epsom Salt Can Do For Tomatoes
Epsom Salt for tomatoes is most beneficial to the tomato plant where some form of magnesium and/or sulfur deficiency exists. Magnesium deficiencies are known to mostly occur in light, sandy or acidic soils. Heavy rainfall and irrigation which results in leaching is also a known cause of magnesium deficiencies. Epsom Salt is not to be used as a substitute for other fertilizers that may be required by the tomato plant.
Amends the soil for benefit of tomato plant
Epsom Salt is used as a soil amendment for tomato plants. Epsomite is naturally occurring in soils. Most soils already contain the necessary magnesium and sulfur. Nonetheless, some growers prefer to add Epsom Salt to their soils at planting or during the life of the plant. The compound is added to tomato plants to enhance plant health and fruit production.
In general terms, Epsom salt for tomatoes can not really be overdone. This makes adding this mineral salt generally of no harm to the plant itself, in most cases. However, the overuse of Epsom salt increases risk of contamination of ground water sources through leaching.
Enhances tomato plant food production system
Tomato plants, like most plants, depend on chlorophyll found in the plant leaves to absorb light. Chlorophyll is the green pigment or color found in plant leaves. Through photosynthesis, the light absorbed by the tomato plant leaves is used to create glucose using carbon dioxide and water. The tomato plant needs this carbohydrate to sustain a healthy life and produce fruit.
There is a critical scientific relationship between magnesium and chlorophyll. Magnesium is an important part of the chlorophyll molecule. It is needed to support conversion of light, water and carbon dioxide into food for the plant through photosynthesis.
Adding Epsom salt to tomato plants that have a deficiency ensures that the tomato plant leaves are healthy enough to support effective photosynthesis.
Eliminates yellow leaves in tomatoes
When a tomato plant is deficient in magnesium, the leaves partially turn yellow particularly on the underside. Typically, the veins of the leaves start turning yellow. A yellowing of veins under tomato leaves is a reliable sign of magnesium deficiency.
Feeding the tomato plant with Epsom Salt can remedy the yellowing of the leaves provided the yellowing is caused by magnesium deficiency. Other causes can be incorrect watering or diseases such as early blight. In such cases Epsom Salt would not remedy the situation.
Improves tomato plant yields
Tilling and the loss of topsoil results in depleted levels of magnesium in agricultural soils. Studies have shown that adding magnesium to plants suffering from a deficiency significantly increases yields. This is one of the reasons behind the use of Epsom Salt on tomatoes. Once the deficiency is corrected using Epsom Salt, the tomato plant can be expected to yield better.
How to apply Epsom Salt on Tomatoes
Epsom Salt can easily be applied on tomatoes. One of the best ways is to apply the mineral salt at the beginning of the plant life. It may, however, be applied at any point during the life of the plant.
Granules mixed with soil
In this method, Epsom Salt is put in the hole where the tomato plant will be transplanted. The mineral salt is mixed with the soil in the hole before planting and watering the tomato tree. Alternatively, after planting the tomato plant. Epsom Salt is sprinkled around the base of the plant before watering. Watering will dissolve the salt into the soil.
Epsomate soil drench
In this method, Epsom Salt is dissolved in water in a container to create a solution. After planting, the tomato plant is then watered with the drench. The plant can be watered, a few more times, with the drench at regular intervals at about twice per month.
Solution quantities that have been suggested are 1 tablespoon of Epsom Salt per each foot of plant height. That is to say, a 2 feet tomato plant will be fed with some 2 tablespoons of the solution. The Epsom Salt is dissolved in 1 gallon of water.
Epsomate foliar application
Epsomate solution can also be applied directly to foliar. Using a garden spray bottle, tomato plant leaves are soaked with the solution. Magnesium and sulfur are directly absorbed by the plant this way. This is a quicker method of getting Epsom Salt in the tomato plant system.
How to use Epsom Salt in the Garden (Video)
In this video, the use of Epsom Salt in the garden is discussed. How much quantities of the compound to use is also considered.
Cons of Using Epsom Salt for Tomatoes
Epsom Salt is not always beneficial for tomatoes. For example, when applied through the soil, Epsom Salt can outcompete calcium for absorption. If the tomato plant fails to absorb enough calcium, this may lead to the dreaded blossom-end rot which has been associated with black spots on tomatoes (pictured).
The science is that magnesium atoms are much smaller than calcium atoms. Plant uptake is thus more efficient for magnesium than it is for calcium. Yet, the tomato plant requires calcium to build cell walls as well as to fruit.
To avoid Epsom Salt competing with calcium, the mineral salt is applied through a foliar spray.
Apart from the competition, inconsistent watering of tomatoes is one of the main reasons for blossom-end rot. When the soil is too dry, the tomato plant fails to uptake needed nutrients. This makes it vulnerable to the disease.
Myths & Claims about Epsom Salt for Tomatoes
There are some myths and claims associated with the use of Epsom Salt on tomatoes. These claims have not been validated by science.
Helps with seed germination
It has been claimed that the use of Epsom Salt helps seeds germinate. No viable scientific evidence has been presented to support this claim. By their very nature, seeds have all the nutrients needed to facilitate germination.
This is demonstrated by their ability to easily germinate and grow on moist paper and other such mediums. Certain factors such as watering and soil warmth affect the germination rate of tomatoes. However, these factors are not improved nor relieved by the use of mineral salts such as Epsom Salt.
Helps plants grow bushier
Epsom Salt has been said to cause tomato plants to grow “bushier” or lush. This may hold true as far as the existence of a deficiency. Epsomite corrects magnesium deficiencies in plants which positively impacts chlorophyll production.
Chlorophyll makes tomato plant leaves lush. A tomato plant with magnesium deficiency can be remedied of the deficiency and return to flourishing growth by using Epsom Salt. A plant with no magnesium deficiency is not expected to gain any benefit from the use of Epsom Salt.
Improves phosphorus and nitrogen uptake
It has also been claimed that Epsom Salt improves the ability of tomato plants to uptake phosphorus and nitrogen. Again, the real issue points to magnesium deficiency. A deficiency in magnesium or sulfur compromises the uptake of a variety of nutrients including phosphorus and nitrogen. Additional Epsom Salt, where there is no deficiency, has not been scientifically shown to improve uptake of phosphorus and nitrogen.
Conclusion
Epsom Salt for tomatoes is applied in solution form or as granules in the soil or at the base of the tomato plant. Epsom Salt is available inexpensively online and in most gardening shops. Although popular in the home gardening community, Epsom Salt is scientifically useful on tomato plants suffering from magnesium or sulfur deficiency. There is a strong suggestion that applying Epsom Salt on tomatoes with no deficiency has no overall benefit to the tomato plant. Instead, there is a concerning risk of the chemical compound contaminating water bodies through leaching.
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