Epsom salts are a naturally occurring mineral. They were first discovered in Epsom, England, where they got their name. You can find cartons of Epsom salt in drug stores and groceries, either in with the laxatives or the sore muscle section.
What do Epsom Salts do for Plants?
Epsom salts contain hydrated magnesium sulfate, two elements crucial to plant growth.
Sulfur (13%) is crucial to the inner workings of plants, but it is almost never lacking in the soil, thanks in part to synthetic fertilizers and acid rain.
Magnesium (10%) can become scarce in soil, usually because of erosion or depletion of the top soil or a pH imbalance. Some plants, like lettuce and spinach, don’t mind going without magnesium. Others may exhibit symptoms like leaf curing, stunted growth, that could be attributed to more than one cause. Magnesium deficiency has even been blamed as a cause for biter tomatoes.
In general, magnesium plays a role in strengthening the plant cell walls, allowing the plant to take in the nutrients it needs. It also aids in seed germination, photosynthesis and in the formation of fruits and seeds.
Do Epsom Salts Really Help Plants Grow Better?
Researchers have never been terribly impressed with the effects of Epsom salts on plants. Gardeners are a different story and the use of Epsom salts is a gardening tip passed down for generations. While many gardeners simply toss in a handful of Epsom salts at planting time, it really is wiser to test your soil first. Epsom salts are not going to cure an extreme magnesium deficiency. However, experienced gardeners have been swearing by Epsom salts for years, and folk wisdom is often ahead of scientific study. The three plants that benefit most from an application of magnesium in the form of Epsom Salts are: Tomatoes, Peppers and Roses
Epsom Salts for Tomatoes and Peppers
Tomatoes and peppers may show signs of magnesium deficiency late in the season, when their leaves begin to yellow between the leaf veins and fruit production decreases. Whether you will get more and/or larger fruits will depend on many things in addition to using Epsom salts, but using them does seem to have some benefit.
Either mix in 1 T. of Epsom salts into the soil at the bottom of the planting hole when setting out transplants or mix the 1 T. in a gallon of water and water the seedling.
Follow-up with a foliar spray of 1T. per gallon of water when the plants start to flower and again when the young fruits start to form. Try it on a few plants and see if you can tell the difference as the season goes along.
Don’t worry about being exact as to when you apply the Epsom salts. This is a home gardening remedy and there are as many formulas as there are home gardens. Some gardeners only add Epsom salts at planting time. Others like to water or foliar feed with Epsom salts every other week. In this case I’d recommend a more dilute solution, mixing only 1 t. of salts per gallon of water. And some gardeners simply use the Epsom salts when they remember. It’s all good.