As strange as it may sound, it is possible to grow plants without soil. This method is known as hydroponics. Plants don't technically need soil to grow. They use the soil and to anchor themselves against the weather and to access nutrients and water hidden in the ground. Therefore, if we supply them with a safe place to grow and enough water with the correct nutrients (called a hydroponic nutrient solution), they have no need for soil. Magnesium is one of the nutrients required for plants to grow. Epsom salt is one of the least expensive ways to add magnesium to your hydroponic solution.
Fill your large tub or bucket with 5 gallons of distilled water. Distilled water works better because it lacks chlorine and other deposits that can be found in tap water.
In the smaller bucket, mix 1 cup of distilled water, 1 tsp. of Epsom salt, 1 tsp. of calcium nitrate and 2 tsps. of hydrophonic fertilizer. Epsom salt is available at most pharmacies and grocery stores; nitrate and specialized fertilizer are available at garden centers, hardware stores and nurseries.
Pour the mixture from the smaller bowl into the larger tub and stir with a stirring stick for two to three minutes to ensure the solution is well mixed.