Why might Epsom salt be good for the garden?
Epsom salt contains about 13 percent sulfur and 10percent magnesium. Plants need both of those nutrients. Although most soils already contain sulfur from acid rain, manures and chemical fertilizers, sulfur tends to leach down into lower layers of soil much like nitrogen does, especially when the soil is sandy and there’s a lack of organic matter.
Farms use synthetic forms of sulfur on crops to improve flavor and sweetness. It may even keep some pests at bay.
Magnesium deficiency can negatively impact almost all stages of plant growth from seed germination, to development of fruit. Without enough magnesium, cell walls get weak and plants find it hard to absorb nutrients, especially the primary and secondary nutrients like nitrogen, phosphorus and sulfur.
Where do I find Epsom salt?
If you take a soak in a bath of Epsom salt, take some of the water and use it on your plants!
You might already have some in the house. Lots of folks use Epsom salt to relieve muscle soreness. A box of it is inexpensive, maybe a couple of bucks, especially if you purchase it at a large department store in the health and beauty area instead of a nursery or garden center.
Which plants may benefit from Epsom salt?
I use Epsom salt in the soil and on edibles like peppers, beans, strawberries and potatoes – vegetables and fruit I know may lack sulfur and magnesium. Once in a while I treat my tomatoes with it too.
Combine Epsom salt with…
Eggshells work well with Epsom salt. Also see the Soil Drench Recipe below for ideas.
Prepare a Planting Hole with Epsom salt Recipe
When I’m getting ready to transplant my tomato starts (or any of the edibles listed above) I like to add a tablespoon of Epsom salt to the planting hole.
After growing potatoes in burlap sacks for a few years I discovered that Epsom salt could prevent brown spots so I try to remember to sprinkle some in the bag at planting time. If you grow potatoes in the ground, disperse a tablespoon in the hole for every 4-5 seeds.
Epsom Salt Soil Drench Recipe
After planting my tomatoes I drench the soil around my plants with Epsom salt dissolved in water. I use 1 tablespoon per plant in one gallon of water. I water the plant first, then pour the Epsom salt water on the soil around the plant – not directly on the plant. After about a month of growth, I do it again.
Another variation would be to add 1 cup Epsom salt and 1 cup garden soil to a 5-gallon bucket full of water. Once dissolved, stir in 1 cup alfalfa pellets. Wait a day for the alfalfa to break up and use the water around plants.
I’m concentrating on edibles in this book but I’ll mention quickly that I have also used Epsom salt on my rose bushes and houseplants, especially my the fiddle leaf fig. When I bought it on clearance it looked spindly and diseased, but now it’s doing fine.
Epsom salt Foliar Spray Recipe
Leaves contain small openings called stomata. They open and close like pores to control the rate of water evaporation. They also absorb minerals dissolved in liquids. The rate of absorption varies by plant, leaf structure, environmental conditions and many other factors. Many times, most of a mineral solution sprayed onto the leaves stays in the leaves with only a small amount reaching deep into the plant. That’s ok, the plant will still experience some benefits.
I’ve found the best time to foliar feed with Epsom salt is when the plant is close to developing the edible parts. If you have a lot of plants to spray, prepare a gallon of water with 1 tablespoon salts and fill your spray bottle 5-6 times. If you only have one plant to treat, use a half teaspoon of Epsom salt for each cup of water.
When my tomatoes start developing blossoms, I spray the leaves and try my hardest to spray underneath the leaves too. The undersides of leaves absorb nutrients much faster. I do not add dish detergent to make the spray stick to the leaves because I don’t want to harm beneficial insects.
Epsom salt Quick Tips
- Do not overuse Epsom salt. Because Epsom salt are water soluble, they can leach out of soils quickly, especially sandy soils or those that lack organic matter.
- Nitrogen deficiency can cause a magnesium deficiency in the soil. If your plants are getting enough nitrogen, they may not need Epsom salt.