What Happens when Vaseline is Applied on a Leaf?

Vaseline on leaf

If you have ever tried to cover your plants’ leaves with vaseline, you probably already know that it won’t do anything good for your plant. But what happens when vaseline is applied on a Leaf?

Vaseline will close the pores (stomata) that are present on leaves which are essential for gaseous exchange and evaporation of water. Closing these pores will lead to less transpiration, respiration, and photosynthesis causing the plant to die within a few weeks.

In the rest of this post, I will give you a more in-depth look at what happens when you cover your plants’ leaves with vaseline and at the end of this post I will give you one scenario when you can use vaseline on your plant.

Why vaseline will kill your plant

If you have ever covered all the leaves of a plant with vaseline, you will know that at first, the plant looks fine, but after a couple of days the leaves will start to color and within a (few) week(s), the plant will die.

The leaves of a plant contain small pores (stomata) from which the plant takes in carbon dioxide (CO₂) to perform photosynthesis and allow water vapor to leave the plant. The plant will also uptake oxygen (at night) through these pores in order to release energy to maintain its health.

When you cover up the leaves of a plant with vaseline, you will block these pores of the plant. which will then negatively affect the following processes:

  • Transpiration (water loss through leaves)
  • Respiration (oxygen uptake through leaves)
  • Photosynthesis (carbon dioxide uptake through leaves)

Transpiration is an important process in which water is evaporated through the leaves. This process will cool the plant, change the pressure inside the plant, and will uptake essential minerals from the soil and water up through the whole plant. When a leaf is covered with vaseline, the plant will not be able to make the above processes happen, which will lead to an unhealthy plant.

The next important process is called respiration. This process involves using sugars to release energy for the plant to use. During this process, the plant uses oxygen (most of the time at night). When the leaves are covered with vaseline, the plant will not be able to uptake enough oxygen to release the right amount of energy in order for the plant to stay healthy and alive.

Last but not least is the process of photosynthesis in which the plant uses carbon dioxide and water in order to make its food (sugars). The leaves that are covered with vaseline can’t uptake carbon dioxide, which will stop the process of photosynthesis. The plant is not unable to make its own food.

When all three of these processes stop working, the plant will not have long to live. How long the plant will survive depends on the type, the size, and the health of the plant.

To know exactly how long a particular plant will survive when you have all its leaves covered with vaseline (petroleum jelly) is a good question. Too little research has been done, to know this exactly. I estimate that a plant would survive for about 1-2 weeks, after which it dies.

Impact of vaseline on transpiration

Transpiration in plants is the process in which water moves through the plant and ultimately evaporates through the pores (stomata) on the leaves, stems, and flowers. Plants need water in order to survive.

However, of all the water that the plant absorbs through its roots, the plant only uses about 0,5% of it for growth and metabolism. The rest of the water is evaporated through the pores on the leaves, stems, and flowers.


Transpiration in plants is necessary because it cools the plant to the right temperature, it changes the pressure inside the plant cells, and it ensures that all the parts of the plant get the essential minerals it needs. By moving the water (with minerals) through the plant, all the parts will be provided with enough minerals.

The minerals will be taken by the plant and the water without minerals will evaporate again.

If you cover up all the leaves of a plant with vaseline, you will automatically clog most of the pores that are present on the plant. The plant will not be able to evaporate water through its leaves which will lead to:

  • Less cooling of the plant
  • Wrong pressure inside the plant cell
  • Less mineral transported through the plant

Which will then lead to an unhealthy plant that is soon going to die.

If you like this type of content, definitely check out: How do Plants and Animals Relate? (Fully Explained)!

Impact of vaseline on respiration

Respiration in plants is a process in which the sugars inside the plant (that are produced with the help of photosynthesis) are used by the plant for energy.

This process requires oxygen – YES…. plants also use oxygen when they need it to release energy for their own use. Plants do indeed use their own food.

Respiration occurs in the leaves, roots, and stems of the plant and 24 hours a day.

Although the plant is constantly ‘breathing’ in oxygen, more oxygen is taken in at night (see picture below) when photosynthesis has stopped (because there is no sun to start this process).

With all the leaves of a plant covered with vaseline, the rate of respiration will drastically decrease because the leaves can’t take in any oxygen. The plant will not be able to use enough of its own food for energy which will lead to a weak plant.

Impact of vaseline on photosynthesis

In order for a plant to make its own food – photosynthesis takes place. During this process, (with the help of sunlight and chlorophyll) the plant turns carbon dioxide (CO₂) and water (H₂O) into sugars (C₆H₁₂O₆) and oxygen (O₂).

Below there’s a picture of the formula of photosynthesis.

The plant uses the sugars for food – energy, growth and cellular respiration.

If you cover the leaves of a plant with vaseline, the plant won’t be able to take in enough carbon dioxide to perform photosynthesis. The plant will make less sugar (food) and produce less oxygen.

Because the plant makes less sugar, the plant will not have enough food for itself and become weak over time.

When is it good to use vaseline on your plants?

Like you know by now – covering a plant with vaseline is bad for the plant. However, there is one way you can use vaseline on a plant with a positive outcome.

If you are having trouble with ants or other crawling insects that climb up the plant via the stem – one way to stop them from crawling up the plant is to put a thick layer of vaseline around the base of the stem.

The insects don’t like the stickiness of the vaseline and will stop crawling up the plant. Thereby the plant will not be harmed by the vaseline.

But unfortunately, this is only a temporary fix, as the vaseline will dissolve in a few days and the ants will climb back up in the plant and disturb the peace.