Epsom salt is not only good for soaking aching muscles after a long day in the garden. It's also a tried and true remedy for chlorosis caused by magnesium deficiency. Chlorosis is yellowing of the leaves due to a lack of chlorophyll which is the molecule responsible for making plants green. The result can be loss of leaves, stunted growth and lack of flowers and fruit.
This tomatillo leaf has interveinal chlorosis which is yellowing of the areas between the veins, the veins remain green.
My eggplants are showing signs of chlorosis. You can see the areas between the veins are starting to turn light green.
As it progresses, those areas turn from light green to yellow.
Because there are so many causes of yellowing leaves, I tried to rule out some of them to help to figure out what was the cause. My soil pH tested in the normal range. The plants were not being over watered. The roots couldn't be crowded and my drainage is fine. That left some type of deficiency as the culprit, but what?
From what I have read, if an iron deficiency is to blame, the new leaves and terminal buds will be the first leaves to turn yellow, then it will spread to include the older leaves. If the older leaves are the first to show signs of chlorosis then it is more likely a deficiency of magnesium, nitrogen, or zinc.
In my plants, yellowing is apparent on the older leaves while the new leaves are unaffected.
Enter Epsom Salts to the rescue!
Epsom salt is magnesium sulfate which is a naturally occurring mineral sold in drug stores. It can be applied directly into the soil by mixing 1 tsp to 1 tbsp into the bottom of the hole when transplanting. It can also be applied by mixing one tbsp into a gallon of water, then pour the solution onto the soil around the plants.
The salts can also be used in a foliar spray where the solution is sprayed directly onto the leaves. This allows the minerals to be absorbed quickly and is the method I used. I have a 2 gallon sprayer that I recently bought.
How did I manage before I had one? It wasn't easy. I had a hand sprayer, a little hand sprayer that was exhausting to use. It took forearms of steel to spray the garden. It was the best twenty dollars I've spent in years. For my quick tutorial on how to use a pump sprayer, click here.
Mix 1 tablespoon of Epsom salt in one gallon of water in a sprayer.
My sprayer came with different nozzles. I use the one intended to be used to water plants so it puts out more water than the other nozzles.
I spray the leaves from the top of the plant to the bottom and I spray the soil as well. It is best to avoid spraying in the evenings as moist leaves promote mildew. I try to avoid spraying in the heat of the day too so that the leaves don't get burned. So I usually spray in the early morning hours. This is a quick task that takes only 5 minutes.
I sprayed the eggplants and peppers once a week for the past 4 weeks and the results have been amazing. The leaves that were already turning yellow did not improve, but no other leaves have started turning yellow!! Since the problem seems to be corrected, I decided to stop applying the Epsom salts because I don't want it to build up in the soil. If I see leaves starting to show chlorosis again I will start using it again.
Like Superman, the Epsom salts saved the day!