You’ve likely heard of using Epsom salts in things like baths, but what about citrus trees? I’ve seen it come up here and there online, but there wasn’t really a clear answer on if they’re good for citrus trees. So, I dug a little deeper. Here’s what I found.
Citrus trees can benefit from Epsom salt fertilizer, as it contains valuable nutrients like magnesium that help the tree produce larger fruits. Magnesium also gives your citrus trees healthier leaves that withstand disease. Applying Epsom salt is easy and can be done before and after planting citrus trees.
Curious about what else Epsom salt has to offer your citrus trees, and whether this natural fertilizer is right for your plants? Let’s take a closer look at the benefits of Epsom salt.
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Do Citrus Trees Like Epsom Salt?
Epsom salt is good for citrus trees, but only if your tree actually needs the nutrients. The main nutrient in Epsom salt is magnesium, which is not one of the three main nutrients plants need (those are nitrogen, phosphorus, and potassium), but magnesium is still an important supplemental nutrient for citrus trees.
Epsom salt is a chemical compound known as hydrated magnesium sulfate, which contains two essential plant nutrients: sulfur and magnesium. This soil enhancer is found at most pharmacies and grocery stores.
Magnesium is valuable to citrus trees because it helps them perform many essential functions, and it makes it easier for them to absorb other nutrients like phosphorus and nitrogen.
While Epsom salt does not directly provide these other nutrients, adding magnesium is a good way to reduce the likelihood that your citrus trees will be deficient in them.
So, what happens to a citrus tree without enough magnesium? While a soil test is necessary to help evaluate whether your soil is truly lacking the magnesium it needs, too little magnesium can cause your citrus tree to develop yellow patches on its leaves and produce poor-quality fruits.
When Should You Fertilize Citrus Trees with Epsom Salt?
Citrus trees should only be fertilized with Epsom salt if they are deficient in magnesium. The easiest way to figure out whether your trees need more magnesium is to conduct a soil test, but yellow patches on leaves, tough rinds, and poor production of fruit are obvious signs of magnesium deficiency.
Without conducting a soil test, there are a few ways you can “estimate” that your plants might need more magnesium.
For example, soils that are light and sandy, as well as those that have a higher acidity, are more likely to be lacking in magnesium and other nutrients.
The reason? When sandy soil receives lots of rainfall or is watered frequently, it leaches nutrients out of the soil as it drains. The magnesium may trickle out of the soil, as well.
If you notice that your plants have begun to develop yellow patches in the center of old leaves or even on the base of those leaves, especially those that grow closer to the fruit, a magnesium deficiency could be to blame. Other signs of magnesium deficiency include:
- Leaves that fall prematurely from the tree
- Large yellow patches in a v-shaped point at the leaf tip
- Poor fruit production
- Thick, tough fruit rinds
- Discoloration of leaves
On the other hand, the benefits of magnesium include:
- Improved leaf and chlorophyll production
- Easier to peel fruits with thinner rinds
- Larger fruits
It’s important to note that some types of citrus trees have more abundant seeds. These need more magnesium than the types with no or fewer seeds. For example, limes commonly have no seeds along with some oranges such as sumo oranges.
How Do You Use Epsom Salt on Citrus Trees?
When applying Epsom salt on your citrus tree’s soil, simply sprinkle Epsom salt around the drip-line of your tree (anything under the canopy). However, avoid applying Epsom salt directly to the trunk of your tree, as it can damage or chemically burn the plant. Also, it’s best to dilute it with a deep watering.
If you have a larger area that needs to be fertilized, you can use equipment like a drop spreader or handheld spreader. This will make sure you’re evenly dispersing the salt.
While watering the soil after applying Epsom salt is important, it will also naturally wash into the soil as it rains. If you don’t get a lot of rainfall, consider providing extra water to dilute the concentration.
If you’re applying Epsom salt to indoor trees or those in containers, you can also make an Epsom salt watering solution that you apply once a month.
How Much Epsom Salt Do You Use for Citrus Trees?
For indoor and individual citrus trees, combine two tablespoons of Epsom salt with a gallon of water and apply once every growing season (most commonly early spring, but depends on the variety of citrus). If you have many outdoor citrus trees, use two tablespoons of Epsom salt every nine square feet.
The exact amount of Epsom salt you should use will vary depending on how deficient in magnesium your soil happens to be, along with the age, size, and type of tree you are trying to fertilize.
For both indoor and outdoor plants, you should stop watering and fertilizing with Epsom salt as soon as your plant bounces back from the magnesium deficiency.
At this point, switch to a more balanced fertilizer that is formulated especially for citrus. A good NPK to look for is one with a 2:1:1 ratio, such as a 6-3-3 fertilizer.
Does Epsom Salt Help Citrus Trees With Yellow Leaves?
Magnesium deficiency usually appears as a general yellowing of the foliage during the growing season. However, if the yellow leaves on your citrus trees are caused by magnesium or sulfur deficiency, adding Epsom salt can certainly help.
Many nutrient deficiencies, and even pest and disease infestations, can cause yellow leaves. Because of this, it’s tough to say that adding Epsom salt will completely resolve your tree’s yellow leaf issue.
A good way of telling whether that might be the case is to closely examine the pattern of yellowing on your citrus tree.
You will likely notice this on the tips and margins of older leaves, but the yellowing will spread inward, creating a unique arrowhead shape.
The green leaf tissue will slowly but surely become bordered by yellow margins as the deficiency worsens.
What Happens If You Apply Too Much Epsom Salt?
Since Epsom salt is water-soluble and can be leached from the soil when it rains, too much of it can end up as a pollutant in the water table. Be cautious of the surrounding area and the needs of nearby plants when you apply Epsom salt.
Testing the soil before applying Epsom salt is essential.
If magnesium and sulfur aren’t actually needed, Epsom salt can cause an imbalance of nutrients. Too much can cause salt injury, reducing overall plant growth.
Overuse of Epsom salt has also been linked to reduced root colonization of helpful soil microbes, like nitrogen-fixing bacteria.
Additionally, it can release aluminum from the soil, making it available to plants. This can be dangerous when you are growing edible plants like citrus fruits.
Avoid applying the solution directly to your citrus tree’s leaves. This can cause them to burn and scorch from excess nutrients.
However, if you do apply too much Epsom salt, it is easily reversed. In most cases, you can water your citrus tree and it should cause the salt to leach away from the soil.
Fortunately, it takes a lot of Epsom salt to damage leaves and the tree. Testing your soil and making sure it actually needs magnesium is the best way to prevent this kind of toxicity from occurring.
There are other situations in which magnesium may be present in the soil, but not readily available to your trees. For example, too much calcium or potassium can cause a tree to poorly uptake the magnesium in the soil.
Remember that Epsom salt is water-soluble and mobile in soil. This means it can leach quickly and will only be effective for a short period. Because of this, consider mixing it in with a slow-release citrus fertilizer as needed.