It might seem like a novel idea- treating your lemon tree with the same salts you may use to treat yourself while soaking in the tub after a long day. However, you might not know that Epsom salt is actually a form of magnesium, which is a mineral attributed to helping relax achy and tired muscles when you soak in an Epsom salt bath. While magnesium is both essential and beneficial to humans, it is also essential in the growth process of plants, especially fruiting varieties such as lemon trees.
Magnesium in a mineral present in soil and used by plants during photosynthesis. It is possible for a plant to consume and deplete the surrounding soil of magnesium, resulting in a deficiency that can stunt growth and fruit production.
Because Epsom salt is a form of magnesium, it is an effective and convenient soil amendment for treating magnesium deficiency in lemon trees. It is important that your lemon tree has enough magnesium in order to thrive and produce fruit for years to come.
Read on to find out more about why lemon trees need magnesium and what to do if you suspect your tree has a deficiency.
Why do lemon trees need magnesium?
Magnesium plays a critical role in photosynthesis, the process where a plant turns sunlight, carbon dioxide, and water into its food or fuel to grow. Magnesium is essential for the enzymes in plants to function properly, produce chlorophyll, and synthesize protein, all of which are key parts of the process of plant growth.
When a lemon tree lacks magnesium, it can’t efficiently and completely maintain the cycle of photosynthesis. The leaves will begin to yellow and the tree will produce less, if any, fruit. Because the tree is unable to photosynthesize at a healthy rate, a lack of magnesium can also make the tree more susceptible to other diseases.
What causes magnesium deficiency in lemon trees?
If a lemon tree is not getting enough magnesium, either the magnesium supply of the soil has been depleted, or there is a higher ratio of other minerals present that are interfering with the plant’s magnesium uptake.
Plants use up magnesium in the process of photosynthesis. Fruit-bearing plants such as lemon trees use even more magnesium, as producing fruit is a high energy consuming process. In nature, soil is replenished with magnesium through the slow weathering and breaking down of reserves of compound minerals. If you are keeping a potted lemon tree, this natural process of magnesium replenishment is not occurring. If the soil is not being replenished with a source of magnesium, there is the danger of the lemon tree consuming and depleting the surrounding soil of its magnesium supply.
It is also possible that there might be adequate levels of magnesium in the soil, but also a higher ratio of competing minerals. I.e., if the soil is too rich in potassium, the plant may intake the potassium instead of the magnesium, which would lead to a magnesium deficiency in the plant.
What are the signs of magnesium deficiency in a lemon tree?
The most obvious and visible sign of magnesium deficiency in a lemon tree is the yellowing of the leaves between the veins, or in a v-shaped pattern. The yellowing will occur first in the older leaves of the tree.
Fruit growth may be stunted if at all present. Blossoms may die off before they reach maturity.
Additionally, leaves may curl upward along the edges, indicating a deficiency.
How to test your lemon tree for magnesium deficiency
It is important that you are confident your tree has a magnesium deficiency before applying any amendments, as too much magnesium can also be harmful to your tree.
While yellowing leaves are a tell-tale sign of magnesium deficiency, leaves can also yellow for other reasons, such as under or overwatering. Certain pests can also cause leaf yellowing and curling. Because of this, testing the nutrient levels of your lemon tree’s soil is the only way to be certain the tree is suffering from a lack of magnesium.
Conduct a soil test with a kit found online or at your local nursery. Here’s a link to a highly recommended kit that not only tests for magnesium, but also 14 other essential macro and micro nutrients! With this particular kit, you will send your soil sample away to a lab and receive a personalized report with an analysis of the nutrient levels as well as recommended amendments. This is really helpful, as it is possible your lemon tree’s soil has an imbalance of other nutrients that could be affecting it’s growth, in addition to or instead of magnesium.
How to treat magnesium deficiency with Epsom salt
If treating an indoor or potted lemon tree, completely dissolve the Epsom salt in water before applying to your lemon tree’s soil. Dissolve about 1 tablespoon of Epsom salt to a half gallon of water. Apply to the soil around your tree. Repeat the process once more in a few weeks.
If treating a planted, outdoor lemon tree, sprinkle the soil surrounding the lemon tree with Epsom salt. Depending on the size of your lemon tree, use anywhere from 1 to 4 cups, and sprinkle within a 2-4 foot radius of the trunk. Either let the rain dissolve and water the salt into the soil, or water it in yourself. Repeat the process once more in a few weeks.
Never spray a tree with Epsom saltwater, as this can cause leaf and trunk burn.
Is Epsom salt the best way to treat magnesium deficiency in lemon trees?
Because Epsom salt is a form of magnesium, it is a direct and effective way of treating magnesium deficiency in lemon trees. It can also be an incredibly convenient method if you happen to have Epsom salt around the house for other purposes. If you don’t have any around the house and are looking to purchase some Epsom salt, check this product out on Amazon. It is a 100% pure epsom salt (magnesium sulfate) and does not include other ingredients such as fragrances or colorants, and is completely safe to use while soaking, as well!
Another option is to use a fertilizer mix that includes magnesium in its formula. This can be an excellent option as your plant will likely get a boost in other nutrients from the mix. However, be careful to choose a formula that is not too rich in potassium, as excess potassium can make it more difficult for the tree to uptake magnesium. Look for a formula primarily composed of nitrogen, phosphate, calcium, magnesium, and potash such as this Dyna-Gro formula. Follow the instructions on the fertilizer you choose for the proper dilution ratio and application.
Dolomitic lime is another soil amendment, composed of calcium magnesium carbonate that can be used to treat magnesium deficiency. Run a soil test and check the PH level before using dolomite lime, as the calcium in dolomite will raise the soil’s PH level. If it is aligned with your soil’s needs, however, dolomite lime can work wonders on your lemon tree. It can be purchased at your local nursery or online. Sprinkle a handful around the base of the lemon tree and water it in.