Stimulates rose bloom and cane growth - a magnesium source that helps plants produce chlorophyll Epsom Salt is a highly soluble form of magnesium sulfate, two elements that play vital roles in the uptake of phosphorus and nitrogen in plants, and the production of several plant enzymes. Epsom Salt for plants is a source of magnesium sulfate that is essential for healthy growth and development. It is required to produce chlorophyll which helps plant life obtain energy from light. It also gives plants their healthy green colour. Leaf yellowing is often a symptom of deficiency How to Water Plants with Epsom Salts Before applying Epsom Salt, it is a good idea to have your soil tested to determine whether it is deficient of magnesium. You should also be aware that many plants, like beans and leafy vegetables, will happily grow and produce in soils with low levels of magnesium. Plants like rose, tomatoes and peppers, on the other hand, require lots of magnesium, and therefore, are more commonly watered with Epsom Salt. When diluted with water, Epsom Salts is easily taken up by plants, especially when applied as a foliar spray. With roses, you can apply a foliar spray each foot of the shrub's height. Apply in spring as leaves appear and then again after flowering. For tomatoes and peppers, apply during transplanting and again following the first bloom and fruit set. Magnesium (Mg): 9.8% Sulfur (S): 12.9% Application Frequency Apply every 2 - 3 weeks (14 - 21 days)