Epsom salts are not a new secret by any stretch, but how reliable are they? Perhaps they are more of a myth than a secret, scientific research does not bold well, but anecdotal evidence seems to say a different story. If there is no harm to adding Epsom salts to your roses, what’s to stop you?
Why Would Epsom Salts Help Your Plants
Epsom salts are hydrated magnesium sulfate (MgSO4), which is made up of sulfur and magnesium. Magnesium is a wonder worker in the garden as it allows plants to take in nitrogen and phosphorus. Magnesium is also needed for chlorophyll production. That all important chemical that allows for photosynthesis to take place.
Soils that are depleted of magnesium tend to be described as sandy or acidic or even occasionally clay soils that have been intensively farmed. You can do a quick soil test, available via Amazon here, to determine if your soil falls into one of these categories.
There is little in the way of scientific evidence to show that adding to healthy soil increases productivity. However those controlled tests all involve watering with Epsom salts and not applying in a foliar manner. Making sure to apply to the leaves later in the day, avoiding the heat of the midday sun. As long as you avoid scorching of the leaves, Epsom salts has some great anecdotal evidence to suggest a greater yield.
Which Plants Benefit From Epsom Salts
In commercial settings magnesium is quickly depleted. In more domestic settings, even an allotment, it is always worth testing soil first.
- Trees like apple, plums, citrus, banana and even commercially grown conifers. Mainly in commercial settings where there has been significant depletion of the magnesium in the soil. At home you would add Epsom salts to the hole you dig prior to planting and then as a regular foliar feed.
- Beets, sugar beets, potatoes, sweet potatoes and carrots. At home you may use a patch of land that isn’t as nutrient rich for your potatoes, but this is more for commercial growers. Epsom salts in your garden can be added to the liquid feeding regime for tuber plants.
- Epsom salts have a close association with roses and producing an abundance of flowers. Dig in prior to planting and then incorporate into your foliar feeding system. Paying attention to avoid scorching of the leaves.
- Tomatoes are traditionally fed by Epsom salts or alternatives that are designed to do the same role. When we think about the vibrancy of color in our crop, we need adequate photosynthesis to occur to make the most of the sunlight hours provided. In the UK we are not guaranteed 8-10 hours of sun a day in the growing season, so optimizing those hours is key.
- We grow hops at home and regularly use Epsom salts to improve the soil. This is important when growing the same crop year on year in one location. Hops do require a lot of magnesium in the soil and will be able to make better use of the nutrients present in the soil when you apply the salts.
- Peppers also need a lot of magnesium to really thrive. You can mix in Epsom salts to the soil prior to planting out, as well as incorporating into your foliar feeding methods.
- As part of your lawn care regime. So many home gardeners swear by adding Epsom salts to their watering in the fist few weeks of Summer. Bare in mind to water late in the evening, once the heat of the sun has gone. Mix 2 tablespoons to one gallon of water and spray the lawn as a top up to any watering schedule in place. It will help to make your lawn more green and vibrant.
How To Use Epsom Salts In The Garden
You have several methods to deploy here. Lets look at each process in more detail.
- Soil incorporation of Epsom salts is quite common practice in commercial settings. If you want to replicate this at home you will be looking at around 1 cup or 200g required for approximately 100 foot square of soil. Scatter and work through. This is only a good idea if you do not have surface run off issues as the magnesium will leech into nearby river systems.
- Putting into a new planting position. Often when we apply Epsom salts to a freshly dug hole we do so without thought. It is not a habit that you need to worry about as it is shown to be a slow release and not a risk of over feeding as with more mass produced products. A tablespoon is adequate for a medium sized shrub, rose or similar flowering perennial. Simply dig the hole, scatter the Epsom salts and then sprinkle with a new layer of soil to stop direct contact with the roots.
- Soaking root balls prior to planting. My theory is that most plants benefit from a good soak when being planted out. So your apple tree, rose plants, plum trees and so on will benefit from 1 cup (200g) of Epsom salts in 1 gallon (4.5 litres) of water. Whether it has been scientifically proven or not, it will not harm your plants.
- In potted plants as top feed. Just where you would normally add your fertilizer, sprinkle around the base of the plant, making sure not to dust the leaves at all.
- In water form as a liquid feed. This is an easy win as you will need to feed through the growing season. Dissolve around 2 tablespoons of Epsom salts for every gallon (4.5 liters) and apply when growth first starts in Spring and then every few weeks during the real growing period. If watering in the day time, water towards the base of the plant to avoid scorching of leaves.
- As part of a foliar spray. This is a great way to deliver Epsom salts to plants that need strong foliage. 1 tablespoon of Epsom salts to every gallon of water used. Spray tomatoes and peppers when they are being transplanted and have started to flower. With roses spray in early Spring and once they start to produce buds. A word of warning around risk of scorching when applied in the morning, the salts will not evaporate in quite the same way as morning dew will.
- As a pest control measure. Epsom salts have been used for years to deter slugs and snails from eating your plants. Simply put they cannot cross a line of sulfur to get to your plants. So this is one of a many pronged strategy to defending your plants. Use the salts liberally to make a circle of protection around each plant. This will need to be reapplied after heavy rains or even after each week really. You may also need the usual beer traps and dried egg shells to double down on slug and snail protection.
- Epsom salts used as part of a weed killer. Not a way that we find useful as all weed killers have the possibility to harm the plants we want to keep alive. We also believe in composting all the weeds we can, so a spray with vinegar and liquid detergent is not suitable for our organic and more harmonious approach to gardening.
- As a muscle relaxing bath soak! Totally different Espom salts needed here, but really worth it after a long day in the garden. It is also a really nice way to soak all of the little burrs and splinters out of your hands as well. We do use scented Epsom salts for a relaxing bath, as it really helps to loosen those muscles that you didn’t think you even had.
Options To Use Instead Of Epsom Salts
- Homemade Compost is always to be preferred as it is the ultimate in zero waste. Add kitchen scraps, chicken bedding and poop as well as horse manure. Leave it all to warm through and do it’s thing before adding directly to the soil.
- Green Manure is so much easier for a gardener. You can sow seeds over winter for crops like Borage or clover. In the case of borage it has a very long tap root that will drill down and bring up all of the nitrogen and nutrients. Then it dies off in time for the next seasons crop and you simply dig it through the plot.
- Organic Fertilizer. You can choose from a wide range on the market and they are all intended or different roles. The main ones you will need in place of Epsom salts are for tomatoes or roses. Vitax make an organic rose fertilizer available via this link. Which can be mixed in with soil or used a soil topper. Maxicrop make an organic tomato feed from seaweed, available here. The more natural the better for your overall soil health.
- Organic Liquid Feed is easy to make yourself. Although this herbal tea stinks to high heavens. It is just the leaves and stalks of borage or fenugreek etc left in a water butt for several weeks. You dilute it before spraying or watering but it acts in much the same way as a foliar spray would.
We do not recommend adding Epsom salts to a bed that has not been tested first. Once you know there is a deficiency , you can add. However adding Epsom salts as a foliar spray really does seem to have some support from the gardening community. The general consensus seems to be, if added to the foliage it is not doing any harm, but it seems to really improve foliage production and vibrancy. So why not add some to your spray?
For digging in and watering try organic alternatives, certainly never add chemicals to a garden you intend to eat from.
Further Reading & Shopping Options
- Green Manure – What, Why and How!
- Growing Comfrey From Seed Or Root Cuttings
- Borage – How To Sow, Grow And Harvest
- How To Make A Bee Friendly Herb Garden
- The Best Mulch To Use In Your Garden