Epsom Salt for Cucumbers [Detailed How-To Guide]

In this article, we would look at all aspects of using Epsom salt for cucumbers. These include the amount of Epsom salts to be used, how to get the right Epsom salt solution for watering, the frequency of usage, and how to apply Epsom salts to the cucumber plants.

As in all farming cases, the wish of every cucumber grower is a bountiful harvest at the right time. But, things might not go as planned and ensuring that the plants produce healthy cucumbers might become a struggle. The first sign of a disaster waiting to happen are the leaves turning yellow from lush green.

This is a clear case of nutrient deficiency.

To salvage the situation, or even to prevent it from happening in the first place, several strategies can be employed. One of the easiest and safest is to use Epsom salt for the cucumbers you’ve planted.

Using Epsom salt for cucumbers as plant therapy is rooted in the idea that nutrients deficiency in plants (and the soil) can be reversed via the right methods. The two main components of the compound, magnesium and sulfur, have proven over several generations to be a panacea for nutrient-deficient soils and plants including cucumber.

Signs That Your Cucumbers Need Epsom Salts

Plants would show visual cues when they are deprived of certain nutrients that are essential for growth and development. Cucumbers are no different. This makes it important for farmers to keep a close eye on the plants so they can nip the problem in the bud before it gets out of hand.

For very meticulous farmers, waiting for these signs is not an option. They regularly test the soil to see if all the vital nutrients are present in the right proportions. Testing can be carried out easily by sending samples of the soil to testing centers in the locality.

However, this proactive measure is not everybody’s cup of tea. For many people, especially small home gardeners, carefully observing the plants for signs of less than optimal growth is the default strategy.

For cucumbers, some of the signs to watch out for include;

Discoloration of younger leaves – The most common color when this happens is when the leaves turn yellow from a healthy green. This is most likely due to deficiency sulfur or magnesium.

This discoloration usually occurs between the veins of the leaves at the base of the affected plant. Note that in most cases, the veins would still remain green.

Smaller plants and fruits – Another red flag is if the plants are relatively smaller than expected. If the problem is not dealt with immediately, the harvest would be disappointing with most of the cucumbers less that the size of an average cucumber with the fruits taking quite a long to mature.

Instead of the plants producing normal cucumbers, they’d be using up the little nutrients available to conserve energy instead. This is basically a survival mechanism in a hostile environment by the cucumber.

Benefits Of Epsom Salt For Cucumbers

Replenishes soil nutrients – Loss of nutrient is a common occurrence especially when the soil is sandy. Over time, these nutrients leak out of the soil or are washed away either by rainwater or after prolong watering of the plants.

Adding Epsom salt is akin to using fertilizers as it repairs the damage done by the depletion of the nutrients. The sulfur and magnesium in the compound help in the synthesis of other nutrients such as nitrogen, enzymes, and proteins in the plant.

For photosynthesis – Magnesium is one of the most vital elements in the photosynthetic process. Adding Epsom salt to the soil or watering the plant with it helps to produce greener plants packed with chlorophyll. The chlorophyll helps in capturing energy from the sun that is used in photosynthesis.

Aids nutrient adsorption – Several studies have indicated that the magnesium-sulfate combo does increase the uptake of important nutrients by plants. Some of these nutrients include phosphorus,  sulfur, and nitrogen.

Controls pests and bugs – Using a mixture of Epsom salt and water (about 40 ml to a gallon of water) can act as a deterrent to garden pests such as beetles, snails, and grubs.

The dry salt crystals can also be used for the same purpose by sprinkling it lightly around the young plants. The salt would quickly dry up the outer covering of pests like slugs and ultimately killing them.

How to Use Epsom Salt for Cucumbers

There are several ways to use Epsom salt for Cucumber to aid their growth. To be clear, the method you use would depend on several factors. What works best for somebody you know wouldn’t necessarily work for you too. You simply have to decide on a method that you find convenient. All things being equal, the results should be the same.

Some of the methods include:

Watering cucumber with Epsom salt solution

Instead of just watering the cucumber plants with plain water, you could use an Epsom salt solution to deliver the desired nutrients.

The recommended ratio of salt to water is 1 tablespoon to a gallon of water respectively. Ensure the solution is stirred very well to dissolve the crystals before use. Then use the resulting solution to drench the plants for a day.

If you have to repeat this, allow a lapse of about 4 weeks. You’d only do this if the symptoms of the deficiency persist. But you should take samples of the soil for testing if the problem is still present three weeks after the second application. It’s very possible that magnesium-deficiency is not the root cause of the problem.

Foliar Spray

Some cucumber growers chose to directly target the leaves by spraying them with the Epsom salt solution. The plan is to deliver the nutrients to plants via absorption by the leaves.

Unlike the previous method, this is not a substitute for normal watering for the day. So you still have to water the plants the normal way.

For this method, the solution is made by dissolving 2 tablespoons of Epsom salts in a gallon of water. The solution is then poured into a handy spray bottle that would be used to spray the leaves.

If necessary, repeat this after a month.

Side Dressing

Though this method is not as common as the first two, it works brilliantly and can be an option for maturing cucumber plants. The obvious upside to this is that you won’t have to go through the process of making a solution first.

At mid-season, simply spread the dry crystals around the base of each plant. This method can only be used once. More than once would likely hurt the plant

Before planting the seedlings

Epsom salt can be incorporated into the cucumber garden before planting the seedlings.

You could:

  • Mix about 2 tablespoons of the crystals with the soil before planting your cucumber seedlings
  • Add a tablespoon of the salt into the hole before planting the cucumber seedlings
  • Mix 2 tablespoons of Epsom salts to your regular fertilizer

These methods must only be used if you are sure the soil doesn’t have the full complement of organic material and nutrients required for the development of healthy plants.

On the other hand, if the soil is very healthy and you had enriched it with compost, using any of these methods are totally unnecessary. The rule of thumb is to wait for the plants to grow and observe for any signs of ill health or deficiency of nutrients before employing them.

General tips on treating cucumbers with Epsom salt

In an ideal world, cucumber growers won’t have to use Epsom salt to rejuvenate their plants. The soils should contain all the nutrients needed.

But the best practice before using the salt is to test the soil to confirm there is a magnesium/sulfur deficiency or not. And when it becomes inevitable, the rule of thumb is to limit the frequency of use to not more than once per month.

And most importantly, it is bad to use Epsom salt as a fertilizer substitute. It is not. Frequent applications as is done with fertilizers might harm both the soli and the cucumber plant.


For gardeners, one pain that must be avoided at all costs is nutrient-deficiency in the soil. So it is the smart farmer that adequately prepares to deal with the problem when it occurs.

Cucumber plants, like other plants, would benefit from a nutrient supplement if the plants are not growing the way they should. For instance, yellow leaves (instead of lush green leaves) is a clear clue the plant is lacking magnesium that could be resolved easily with Epsom salt.

The best practice before opting to use Epsom salt is to test the soil to determine the nutrients lacking. Tests that show magnesium and sulfur deficiency are prime candidates for the use of Epsom salts.

The bottom line for cucumber growers is making sure the plants are healthy and the harvest optimal. And Epsom salts provide some of the easiest and cheapest means of achieving that objective.