Is Vegetable Oil Good for Gardening Soil?


Most gardeners know that healthy soil is essential to thriving, growing plants. Because of this, most of us are willing to do whatever it takes to get healthy, nutrient-rich soil. There is an old wives’ tale about vegetable oil being good for gardening soil, but is it true?

Vegetable oil is good for gardening soil. Research has shown that vegetable oil can help increase nutrients in the soil, retain the moisture of soil, and even help dispel weeds in the soil. Applying in the right amounts and with the proper methods is essential. 

Like all things, the quantity of vegetable oil you use is going to be an essential factor. Using too much vegetable oil will damage plants and could possibly kill them. Below, I’ll discuss why one might attempt adding vegetable oil to their gardening soil and how to do so safely.

Can I Use Vegetable Oil on Gardening Soil?

We want our soil to be soft, nutrient-rich, and porous, and we want it to be full of healthy tiny microorganisms that can help our plants. However, vegetable oil might raise some red flags.

You can use vegetable oil on gardening soil. When applied properly and in the correct quantity, vegetable oil can add nutrients, support moisture retention, rid plants of pests, and even work as weed control. Don’t apply directly to a plant. 

Vegetable oil benefits the soil, but that doesn’t necessarily mean it benefits plants. 

There are many instances that you may consider bumping up your soil’s nutrients, water retention, or ridding it of microorganisms, pests, or weeds. For a good amount of these instances, plants don’t have to be involved.

For example, if you found an invasion of a harmful species in your gardening pot, you may choose to remove the plant and repot it somewhere else. 

But, to save money and recycle, you may attempt to keep the soil. You can sanitize it using heat or freezing methods, but adding a little vegetable oil doesn’t hurt either. Or, if you have a dirt path in your garden or yard without any plants, and you want to rid it of weeds, you may use it.

The problem comes in when you choose to add vegetable oil to your soil while there are still plants growing in it. It’s possible to do this safely, as you need to apply small amounts and use Q-Tip methods or misting. However, you’d avoid it and use it as a last-ditch effort. 

What Vegetable Oil Does to Gardening Soil

Vegetable oil straight out of the frying pan isn’t suitable for your trashcan and isn’t good for your garden. Hot oils can fry your plants and damage soil, killing anything living in it, good or bad.

However, adding a teaspoon or relative amount to a garden has proven to have a few benefits.  If you want to use your used frying oil, be sure to let it come to room temperature and filter out the food particles before adding it to your soil.

One child’s science experiment at the USC state fair proved that vegetable oil added to the soil can make plants grow faster and retain nutrients better. He concluded that this was because of the additional nutrients provided by the vegetable oil and its ability to act as a protective bubble for moisture.

Additionally, neem oil has long been necessary for a gardener’s tool kit to help with pests, insects, and molds. Vegetable oil works in much the same manner, making plants and soil slick and tricky for pests to stick onto.

Lastly, some research has shown that vegetable oil can be a helpful aid in pest control.

Importance of Moisture in Garden Plants

Plants need water, sunlight, and good soil to grow. Moisture is one of the most critical factors in a healthy garden and healthy soil. Plants without water wither and die, and plants waterlogged or drowned in water also die. 

Finding the balance between soil and water for your garden might be hard work, but it’s essential. 

If you find yourself having problems with moisture retention or think water is dripping through your plant pots too quickly, you might jump to the solution of vegetable oil. Vegetable oil has been proven to have moisture retention properties, but there are quite a few other tactics that you can try first. 

You can check out the composition of your soil and make sure it isn’t hydrophobic, change your watering routine or create an irrigation system in your backyard.

Nutrients and Your Soil

Healthy soil means having plenty of nutrients available to your plants. A lowly acidic pH to just neutral, between 6.0 and 7.0. If your soil pH is any higher or any lower than this, your plants will not be able to absorb the available nutrients in your soil. 

When your plants can’t absorb nutrients, they can’t grow effectively. 

Vegetable oil has been proven to lower soil pH. So, if your soil is becoming more alkaline, you may consider using vegetable oil. However, this isn’t the only way to make your soil more acidic or nutrient-rich. 

Adding compost, mulch, or microorganisms usually does a great job of making your soil pH balance out without killing anything already living in your soil.

Weed and Pest Control 

Oil has been long used as a natural solution for both pest control and weeds. 

One of the most common oils to use is neem oil for pest and control. Not only does it make it difficult for mold to grow and pests to stick to, but the scent also repels insects. Vegetable oil can also make it difficult for insects to stick to plants, but the scent doesn’t have the same repelling effects. 

Other options for weed control are:

Vegetable oil is an easy thing to grab from the pantry for weeds, but vinegar is also a common weed repellant that’ll likely work more effectively. 

However, you’ll want to be very cautious of the repellant getting onto your plants. 

Bottom Line: You Can Add Vegetable to Soil

You can add vegetable oil to your soil, but should you? That is a question you’ll have to answer yourself. There are dozens of alternative strategies to support your soil’s moisture retention, decrease its pH, and rid it of pests and weeds. 

However, if you’re looking for a quick fix without a trip to the store, vegetable oil may help. 

Should I Put Vegetable Oil on Plants?

If you want to use vegetable oil for your soil or help you with weed control, you should know the proper way to apply it. Vegetable oil may work for soils, but foreign substances aren’t always suitable for plants. As always, research the plant, vegetable, or fruit in question. 

You shouldn’t put vegetable oil directly onto plants, but it can be used for cleaning or pest control. Instead, use a misting method or a Q-Tip to apply small quantities. If you get a large amount of oil on your plant, you risk damaging or killing it.

Additionally, going in too heavy-handed with any solution can damage a plant or bruise your produce. Using gardening gloves is always the best practice for interventions in the garden. 

Mixing some oil in your soil or applying it to weeds is an entirely different ball game than using it for your plants. Oil is usually helpful for getting pests off of plants and can even help clean your plants, but this should be done gently. 

Also, it’s always a good idea to find the most organic or pure version of a substance if you put it on your vegetables or plants. 

This might go without saying, but you also need to make sure the vegetable oil is at room temperature. Hot vegetable oil should be disposed of properly. 

How To Apply Vegetable Oil to Plants

If you plan to use vegetable oil or any oil, it’s best not to dump the oil into the plant. 

You’d only use a small amount, either on its own or diluted with soap and water. Additionally, you’d use gentle methods to apply it to the plant. You can dip a Q-Tip into a cup, apply gently to the leaves, or use a mister bottle.

Vegetable oil may work in a pinch, but other oils are safer and more efficient. You can try neem oil, which is a popular choice for gardeners. Additionally, soapy water also works well for getting rid of pests. 

Final Thoughts

Vegetable oil can be helpful for soil retention, lowering pH, or getting rid of unwanted things in your garden. However, it isn’t the only thing that can help with these common gardening issues. If you’re on a budget and do not want to make a trip to the gardening store, vegetable oil will work, but make sure to apply it gently.

Alexander Picot

Alexander Picot is the principal creator of TheGrowingLeaf.com, a website dedicated to gardening tips. Inspired by his mother’s love of gardening, Alex has a passion for taking care of plants and turning backyards into feel-good places and loves to share his experience with the rest of the world.

Recent Posts