I hope your peppers survive the essential oils and the Epsom Salts bath. Epsom Salts is Magnesium Sulfate, two minerals plants do need but in very minute amounts. In a home situation, if you are using a well balanced fertilizer, your plants don't need extra Magnesium or extra Sulfates. If they do show signs of deficiencies of trace minerals, it is usually a pH problem, not a nutrient problem.