Answer: Yes, some rose growers swear by epsom salts. It's Magnesium sulphate, a combination of two of the secondary nutrients which soil scientists talk about. Both are essential to plant growth and both are used by plants in significant quantities. Both also have a bearing on the uptake of other plant nutrients. The good news is, rarely is there a deficiency in soils that would require the supplementing of these nutrients and, if you're using other complete fertilizers, you're already adding magnesium and sulfur. If you've had a soil test performed (cooperative extension service or independent soil lab) and it's been determined that sulfur and magnesium are deficient, you may want to add Epsom salts (if you're not already applying other, complete fertilzers). A recommended dosage would be 1/4 cup (or 1 tablespoon to 1/2 cup, depending on age and size of plant) per rose plant, applied in spring.
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