How long does neem oil last?” is something everyone interested in using a neem oil insecticide should know about. While this oil has great potential as a natural plant pesticide, it has a minimal shelf life.

An Article About How Long Does Neem Oil Last Plant America The gardener must know how long these oils' various forms last. This brief article will teach you about all these shelf lives and much more.

How Long Does Neem Oil Last on Average?

💥 Quick Answer

Neem oil lasts one to two years on average in a sealed bottle. Only the best quality and adequately stored oil will last three years maximum. Once its bottle is opened, the oil barely lasts five to six months and around 12 hours when mixed with water.

– The Shelf Life of a Sealed Bottle

A sealed bottle of neem oil stored under perfect conditions can last about one to three years. Most oil preparations last up to one year despite being sealed in an airtight and dark bottle. Only the most high-quality products will make it to three years before they need to be thrown away.

Even the most premium-quality oil does not have a very long shelf life because this oil is inherently unstable in nature. From the moment it is extracted from neem seeds by cold pressing, its disintegration begins. That is why it must be used immediately after being cold- pressed.

– The Shelf Life of an Unsealed Bottle

Neem oil expires pretty fast once the seal of its bottle is opened. Most manufacturers clearly state that their oil should be used within six months of being opened. This is because once the lid is open and the oil is exposed to the outside environment, the process of oil disintegration accelerates rapidly.

The Shelf Life of an Unsealed Bottle Plant America

Exposure to light and moisture in the air rapidly accelerates the breakdown of molecules within this oil. To make one bottle last longer, put its lid back on right after pouring the amount you need. Another helpful piece of advice is to always purchase a tiny bottle that can be used within six months so that extra oil does not have to be thrown away.

– Life of Oil and Water When Mixed

Neem oil works on plants as a pesticide only when it is diluted with water first. This mixing with water drastically decreases the lifespan of oil, and it lasts barely six to 12 hours. This is why there is no point in making a neem oil solution for plants ahead of time.

After mixing with water, this oil can stay for a maximum of 24 hours, after which it expires. Again, keep the mixture in a tightly closed container placed in a dark and dry room. Once the oil and water mixture expires, using it is futile and can harm the plants.

– Life of Neem Oil on Plants

When you spray neem oil on the plants, it will last from around two to three days maximum. This is when the spray is made by diluting this oil with a large quantity of water.

It has been estimated that the effectiveness of this spray decreases by 50 percent every 24 to 60 hours on both outdoor and indoor plants. Because it lasts for about two to three days, a foliar spray should be used at most twice a week.

What Makes Neem Oil Last a Long Time?

🔥 Quick Answer

The right temperature, absence of light, and premium-quality cold pressing make neem oil last a long time. The temperature range at which this oil remains stable is between 77 to 80 degrees Fahrenheit. It is a mistake to store it in the refrigerator for longevity.

– The Right Temperatures

You must store neem oil within a temperature range of 77 to 80 degrees Fahrenheit at home. It doesn’t matter whether it is summer or winter outside; this is the ideal temperature range for this oil. At temperatures above 80 degrees, this oil begins to break down and expire faster than average.

Wooden Thermometer On a White Background Plant America

Below 70 degrees, the oil solidifies and turns into a mass. It is a mistake to heat this solidified mass to turn it back to liquid form for use on plants. Heating this oil will expire faster and might even turn it rancid immediately. Just put the solidified oil bottle at room temperature until it returns to its original liquid form.

– No Exposure to Light

Let’s not forget that light is also a form of energy and helps accelerate the breakdown of organic neem oil.

Always store this oil in a dark bottle that does not allow any light to pass through it.

This bottle can be made of plastic or glass; it doesn't matter as long as it is thick enough not to let light pass.

Even when the bottle is dark and opaque, it must be placed in a dark cupboard or pantry. Do not place these bottles near the windows or in a brightly lit kitchen, or else the oil will not last long.

– Good Quality Oil

Even if you store and keep neem oil adequately enough, it will only last for a while if it is low- quality. Many unverified vendors are selling this oil online at cheap prices. These oils are often pressed from low-quality seeds and only appropriately stored after being sold.

Moreover, the expiration date they gave them can also not be trusted. They often expire well before their time, harming your plants more than helping them.

Spending more money on pure neem oil from a verified and certified vendor that will last much longer than other oils is better.

– Not Placed in a Refrigerator

Storing this oil in a refrigerator will not make it last longer and must be avoided at all costs. This oil should not be kept below 40 degrees Fahrenheit at all as it begins to break down at very cold temperatures. Placing it in the fridge will turn it into a solid mass, which is also not recommended.

Inside Of an Industrial Refrigerator Plant America

How Do You Tell That Neem Oil Has Expired?

🔥 Quick Answer

You can tell that neem oil has expired by the appearance of white discolorations, a foul odor, and a thickening of its texture. The oil that has turned rancid might turn brown or black colored. The expiry date on the oil bottle also specifies when it expires.

– The Expiry Date on the Label

Look at the label on the back of every newly purchased bottle of neem oil. The manufacturer will clearly have given a date of about one to two years from the date of manufacturing when this oil will expire.

Sometimes, only the manufacturing date is given, and you can estimate the expiry date after one year. Do not bother purchasing from manufacturers who do not specify either date.

– It Will Have Discolorations

Apply neem oil on plants for pest control only if it is transparent without any white discolorations or opacities. The natural color of this oil varies, depending on the variety of the neem tree from which it was extracted. Mostly, it is bright yellow, pale yellow, or brownish-yellow in color.

Some particular varieties of this oil also come in golden yellow or reddish brown in color. These all are normal color variations of this oil, and you need not worry unless there is white discoloration within the oil. The entirely brown or black oil is also not regular and, more often than not, has expired.

– It Will Have a Bad Odor

A regular neem oil spray or soil drench should not have a rancid odor. This oil has a naturally pungent smell that resembles the scent of garlic and sulfur. Once it has expired, a single whiff of this oil will be enough to tell you that it is unfit for plant use.

– Its Texture Will Change

Typically, this oil has a relatively thick and velvety texture, which makes it easy to use in spray bottles when mixed with water. After it expires, solid lumps that are white or reddish in color within the liquid oil might develop. This change in texture is an unmissable sign that the time has come to get rid of the oil.

What Happens if Expired Neem Oil Is Used on Plants?

If expired neem oil is used on plants, it might end up causing burns to the leaves and the stems. This is because expired oil contains harmful toxins and oxidants. After expiry, this oil loses the ability to kill insects and instead kills valuable bugs.

– It Burns Plant Leaves

Applying neem oil on plants after its expiry will burn their leaves and stems. Even if expired oil is well diluted with water, it is still rancid and toxic for plants. Oil breakdown products contain harmful antioxidants that cause damage to plant leaves on a cellular level. In severe cases, you will have to deal with large black spots all over the leaves.

– Expired Oil Is Not a Good Pesticide

Spraying neem oil on plants infested with pests will not help at all. Pure neem oil is a great organic pesticide that can potentially kill aphids, mealybugs, scales, and other common houseplant bugs. Once the bottle of this oil opens, it slowly loses its effectiveness until it loses its practical effect after six months.

Expired Oil Is Not a Good Pesticide Plant America

– It Might Kill Beneficial Bugs

Neem oil has the ability to kill harmful plant pests while not affecting beneficial insects. These beneficial bugs include essential pollinators like bees and butterflies that help plants produce fruit and flowers.

Expired oil contains toxic chemicals that kill these pollinators as well as the earthworms in the soil. Earthworms are super beneficial and help improve the drainage potential of the garden’s soil.


To conclude, neem oil is safe for plant use when it is used within a limited time frame. Here is a brief recap of how long this oil lasts:

  • It lasts for one to two years in a bottle with a 100 percent sealed cap.
  • Once the bottle opens, the oil will last only five to six months under good storage conditions.
  • After being sprayed on the plants, this oil lasts two to three days and carries out its pesticide action.

After going through this guide, you are better equipped to utilize the power of this oil while it lasts.

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