How much Epsom salts do I use for a gardenia, and how do I apply it?
Certified GKH Gardening Expert
Epsom salt is magnesium sulphate. For the gardenia, it will help prevent yellowing of the leaves. Use 1 tbsp. of Epsom salts per foot of height of gardenia. This article should help as well: https://www.gardeningknowhow.com/ornamental/flowers/gardenia/fertilizing-gardenias-in-your-garden.htm