Magnesium (Mg) deficiency is common in our soils, due to over-fertilisation. When soil is low in magnesium, the foods we grow are low in magnesium, and therefore we get very little magnesium from our diet.
Epsom salt (magnesium sulphate) helps plants to absorb minerals like phosphorous, potassium and nitrogen, which in turn grows bushier plants, with more flowers and fruit. Magnesium is vital for seed germination and for the production of chlorophyll, which plants and trees use to transform sunlight into food. Yellowing leaves is a sure sign of magnesium deficiency. As is leaf curling, stunted growth, and fruit that is not very sweet.
Unlike some fertilisers, which build up in your soil over time, Epsom salt is not persistent, so you can’t overuse it. It’s also easily diluted in water, is easy to apply, and is taken up quickly by your plants.
Plants like tomatoes and peppers require lots of magnesium to grow stronger and provide bigger, juicier, sweeter fruits. Roses treated with Epsom salt respond with greener leaves, bushier plants, and more roses, that are bigger and deeper coloured. Citrus trees also benefit greatly if you want to increase your crop of lemons, oranges and limes.
How to Use Epsom Salt in your Garden
Houseplants – mix ½ cup of Epsom salt in a 10-litre watering can. Feed plants monthly.
Gardenias – sprinkle Epsom salt around the plant base and water in.
Tomatoes and peppers – apply 1 tablespoon per 30cm of plant height every 2 weeks. Water in.
Roses – as with tomatoes. You can also soak unplanted bushes in ½ cup Epsom salt per 5 litres of water to help roots recover.
Fruit trees – apply 2 tablespoons per 3 square metres, 3 times a year.
Another effective way to improve your plants’ take up of magnesium is to make a spray with 1 tablespoon of Epsom salt to 4 litres of water and spray your plants throughout the season.
Garden nasties! At the other end of the scale, Epsom salt can be used as a natural, non-toxic pest control: sprinkle along slug pathways to deter them.
Weed control: mix ½ cup Epsom salt with a litre of vinegar and some liquid dish soap. Use in a spray bottle to kill weeds.
Bonus tip! If you get a splinter while you’re gardening, Epsom salt will help you too! Soak the affected area in a cup of warm water with 2 tablespoons of Epsom salt to help draw out the splinter.