After a hard day of weeding, a good long soak in an Epsom-salt bath soothes aching muscles. But did you know that Epsom salts give roses a boost as well?

Epsom salts are comprised of magnesium sulfate. Both magnesium and sulfur occur in garden soil; they are important secondary nutrients for plants. Magnesium is necessary for plants to generate chlorophyll, which plays an important part in photosynthesis. It also helps plants absorb phosphorus; this is essential for plant growth and vigorous blooms.

Every spring, Martha gives her roses a generous scoop -- one-half to three-quarters cup -- of Epsom salts. She sprinkles the salts in a ring around the perimeter of her rose bushes. Mix the Epsom salts into the soil with a cultivator.

A good way to measure the amount your plants will need is to give them one teaspoon of Epsom salts for each foot of the plant's height. In general, coarse, sandy soils are prone to be lacking in magnesium. Yellowing leaves are a sign that your plant is suffering from magnesium deficiency. If you detect this yellowing, you can try giving your plants an Epsom-salt bath with a sprayer. Make sure you do this on a cool day, at an hour when the sun isn't too strong.