How Often Can I Apply Neem Oil?

Clarified hydrophobic neem oil, a processed form of organic neem oil pesticide, is used in neem foliar sprays.

The majority of the active components in Azadirachtin have been eliminated, resulting in quantities of.5% to 3%.

Neem foliar sprays choke insects on contact and kill some external fungal illnesses and infections as a topical remedy.

However, for it to function, it must be applied every other day for at least 14 days.

To avoid contact with helpful insects like ladybugs and honeybees, apply at night or morning.

After you’ve gotten rid of any existing infestations, you can use the foliar spray once every two weeks as a preventative measure. When using Neem Oil Sprays, be sure to read the Do’s and Don’ts.

How Often To Use Neem Soil Soaks

Pour this neem oil for plants on the soil and allow the roots to absorb it, converting it to a systemic pesticide.

The Azadirachtin will last for up to 22 days inside the plant. Only piercing or chewing bugs will be affected.

Repeat the soil soaks every 21 days to maintain the effectiveness of the Azadirachtin.

Most infestations are killed by azadirachtin without hurting pollinators or useful creatures like earthworms or predator species. It will, however, aid in the treatment of a variety of bacterial and fungal illnesses, including some types of root rot.

When NOT To Use Neem Oil

While neem is non-toxic and is commonly used in toothpaste, it is generally acknowledged that you should not apply it to a food plant on the day it is harvested.

You can use a foliar spray the day before harvest or soil soaks. If you don’t apply it on the day of harvest, you’ll consume less.

Another important requirement is to test a small portion of a plant one day prior to utilizing neem oil goods.

Even natural materials can cause allergies and sensitivities in plants, just as they can in humans.

You can check for evidence of chemical burns or allergic responses by testing a small section of the plant first.

You may only need to test once if you use neem on a regular basis. However, if you haven’t applied neem oil on the plant for a long time, you should always retest it.

You should stop using neem products on that plant right once if you see an adverse reaction during testing or regular use.

Is it possible to overuse neem oil?

Neem oil is an insecticide and fungal that I like to apply on my plants. However, you must be cautious about how and when you apply it to your plants.

If you apply neem oil to plants many times a week, you can overdo it. If you haven’t diluted the neem oil before usage, you may use too much. If you apply too much neem oil to your leaves, it will burn them, turn them yellow, and even kill beneficial insects.

I’ve written about how to tell whether you’re using too much neem oil and how to figure out how much you should be using.

Is neem oil safe to use more than once a week?

As I previously stated, DIY neem oil pesticides can be more effective than commercially available ones. You will receive a high amount of the active ingredient azadirachtin in your solution if you carefully select good quality neem oil probably more than in the store-bought version. Pests are killed by azadirachtin.

Look for 100% pure, cold-pressed neem oil, which is often referred to as “crude” or “raw” neem oil. Because heat destroys Azadirachtin, cold-pressed oils will have a lower concentration of this valuable active ingredient.

You will also avoid any contamination with chemicals or solvents that may come into touch with plants during the standard, uncertified purifying process by purchasing organic neem oil.

Preparing Your Neem Oil Spray

To prepare a neem oil spray, you’ll only need three ingredients: the oil, water, and an emulsifier. Don’t be alarmed by the last word; the bargain is straightforward. Because oil and water do not combine, a light liquid soap (an emulsifier) must be added to the solution.

Basic Neem Oil Insecticide Spray Instructions

gentle liquid soap, insecticidal soap, or another mild detergent, 1/3 tsp (1-2ml) According to some sources, 1 tsp of soap is sufficient.

In a closed bottle, combine the water and soap and shake vigorously to properly dissolve the soap. Shake in the neem oil once more.

The most typical concentration for ordinary and frequent garden use is 0.5-1 percent, though you can try 2 percent sprays if you think you need a stronger solution.

How To Use The Neem Oil Spray?

Before using the neem oil spray on a large area, test it on a small area first. This cannot be emphasized enough.

Spray your solution on the problematic plant leaves, but only on a small area at first so you can monitor any negative effects for a day. After 24 hours, if the plant appears to be responding well to the spray, you can spray the entire afflicted area.

You can apply the neem oil spray as needed or on a regular basis once a week is a good starting point. When you apply the spray on a regular basis, it becomes a preventative treatment, which is especially important if you know you’ll be dealing with a pest infestation soon.

Make sure the leaves are well coated, as with other oil-based sprays, so the active chemicals may make full contact with insects and fungus pests.

Do not spray plants that have been stressed by poor growing conditions, such as drought or overwatering; it is critical to improve the plant’s conditions before spraying to avoid further harm.

Keep neem oil and neem oil spray out of reach of children and dogs to avoid consumption.

How often should plants be sprayed with neem oil?

Some plants may be killed by neem oil, especially if they are young and the oil is applied too heavily. Before applying it all over, test a tiny part of the plant and wait 24 hours. To avoid leaf burning, use neem in the evening to outdoor plants and out of direct sunlight to interior plants. All surfaces of the leaves, including the undersides, should be sprayed. As needed, reapply every seven to fourteen days.

Is it possible for too much neem oil to harm plants?

Researchers have discovered that neem oil includes dozens of different chemical components, but azadirachtin is by far the most important.

This naturally occurring substance does not kill pests right once, but once consumed, it interferes with their ability to feed, molt, and reproduce, causing them to die within a week.

Neem oil coats insects with a thin layer of oil as well. Adult, hard-bodied bugs like leaf-footed bugs, squash bugs, and stink bugs will be irritated but not killed if sprayed with neem oil. Aphids and spider mites, for example, are more vulnerable to anything that coats them in an oily substance, especially if they’re in their nymph stage. The azadirachtin will kill them if the oil doesn’t.

Thankfully, the oil won’t harm helpful pollinators, and once it’s diluted, sprayed on plants, and exposed to sunshine and the environment, it will begin to degrade swiftly.

There are several things you can do to make your neem oil more effective, but in general, you shouldn’t use it more than once every 4-7 days.

In other words, if you use neem oil every 1, 2, or 3 days, you’re overdoing it and risk causing long-term damage to your plants.

This is because neem oil coats the leaves, branches, and flowers of your plants in a thin layer of oil.

As I mentioned above, this oily layer will begin to break down after a few hours, but if you keep reapplying neem oil without properly timing or spacing your treatments so that the oil breaks down completely in between, you risk damaging your plant in two ways.

Foliage Burns

This is the most evident way that neem oil might harm your plants. Simply explained, neem oil is an oil, and it will heat up if exposed to direct sunshine before entirely drying, just like the oil in your frying pan does when exposed to higher temperatures.

When neem oil heats up, it will likely burn any foliage it comes into contact with, generating streaks, splotches, or even spots, as well as eventual leaf death. If you coat too much of your plant with neem oil, you risk killing it completely by damaging too much of its foliage.

Applying neem oil sprays in the early evening is the easiest method to avoid these issues. When the sun is sinking but the light is still bright enough to see clearly, I do so. This ensures that the neem oil has at least 10 hours to dry before the sun rises the next day.

I once forgot to apply neem oil in the evening and, against my better judgment, opted to do so first thing the next morning. I figured that by starting early, I’d avoid getting burned and that it would dry before the sun could do any damage.

Thankfully, I had only used a small amount of neem oil on a few plants, so they recovered quickly. But the incident taught me a valuable lesson: if you skip a neem oil treatment in the early evening, don’t try to make it up the next morning. Simply wait until the right time the next day to spray your plants.

Aside from the risk of foliage burns, regular neem oil applications might have unforeseen consequences on three key biological processes that all plants go through:


Photosynthesis is commonly understood as the process by which plants convert carbon dioxide, sunshine, and water into oxygen and carbohydrates, but how this happens is less well understood.

Simply put, stomata (or stoma if referring to a single pore) are epidermal pores found in plants. By absorbing carbon dioxide from the atmosphere, these small apertures serve an important role in photosynthesis. Cells that serve as gatekeepers surround each stoma. If the plant has enough carbon dioxide, the cells close the stoma to reduce or stop the flow momentarily; if the plant has insufficient carbon dioxide, the cells open the stoma to allow more CO2 in.

As a result, stomata are essential for photosynthesis. They control how much and how often carbon dioxide comes into the plant, so regulating one of photosynthesis’ major components, but not playing a role in the actual chemical processes taking place inside the plant.


Stomata open in order to draw in carbon dioxide, but they also leak water in the process. There’s a lot of it. An acre of maize can transpire up to 4,000 gallons of water per year, whereas a single huge oak tree can transpire up to 40,000 gallons, according to the US Geological Survey.

Heat, humidity, wind speeds, and soil moisture, to mention a few, all influence plant transpiration, but it’s a crucial aspect of the plant’s life cycle, and the stomata regulate when and how much each plant transpires at any particular time.

Oxygen Release

When plants engage in photosynthesis, they collect carbon dioxide from the atmosphere and combine it with water to produce carbohydrates and oxygen using energy received from sunlight. The excess oxygen is subsequently expelled as an unwanted consequence of the photosynthetic activity.

These exchanges, not surprisingly, also take place through the plant’s stomatal openings, especially during daylight hours. As a result, the open stomata serve a dual purpose: they allow CO2 in while also enabling oxygen to escape.

Anything that interrupts these stomatal pathways, as studies have demonstrated, has a negative influence on plants, slowing their biological processes and stunting their growth.

And here is why I’m afraid of neem oil: if you spray too much and too often, you risk coating and re-coating your plant’s leaves in oil, which can block the stomata, making it difficult for the plant to take in carbon dioxide and expel both water and oxygen.

How long does neem oil take to take effect?

The functions of neem oil are dual. The first is to suffocate or smother the insects on your plants. Only little insects, such as spider mites, work well in this area. Because of the compounds in Neem Oil, the second function is to destroy any insect. This will destroy both the tiny and larger insects that may be present on your plants.

Azadirachtin affects the insect’s regular biological activities, causing it to become dormant and die off over time. It’s a non-toxic way to keep pests away from your plants. You are not damaging your plant in any way when you use Neem Oil. On the other hand, you’re making your plant unappealing to insects and pests.

Keep in mind that Neem Oil takes time to work. It takes a few days, usually 3 to 4 days, and several treatments before you start to get the effects you want.

What are the neem oil negative effects?

Children should avoid taking neem seeds and seed oil by mouth. Neem oil can cause serious negative effects in newborns and small children within hours of taking it. Vomiting, diarrhea, sleepiness, seizures, loss of consciousness, coma, and death are among the major side effects.

What is the shelf life of neem oil spray?

You’ve probably heard of the benefits of neem oil as a natural, organic insecticide, whether you’re new to gardening or have been growing plants for years.

However, you may not be aware of how long neem oil lasts, both in terms of its total shelf life and its potency after being blended with water.

Neem oil has a shelf life of 1-3 years if kept in a cool, dry environment. When mixed with water and an emulsifier to make an insecticidal spray, neem oil maintains peak activity for only a few hours but can last up to 3-4 days before its chemical constituents break down completely.

But, for reasons I’ll explain below, just because your diluted neem oil mixture has crossed the 4-day threshold doesn’t imply it’s utterly worthless.

So, let’s look at the various aspects that determine how long neem oil lasts and what you can do to ensure that your neem oil sprays function as intended on your plants.

But first, if you want to produce your own neem oil spray, here’s a list of the items you’ll needand the ones I recommendto get started:

Natural Liquid Soap

When it comes to liquid soap, I have a few choices, but my overall preference is Dr. Bronner’s, especially the larger gallon one because it’s much less per ounce than the smaller bottles:

Garden Sprayer

I’ve yet to find a perfect garden sprayer, so I’ve experimented with a variety of sprayers throughout the years, both cheap and nice:

You may prepare your own neem oil insecticidal spray by purchasing neem oil concentration, natural liquid soap, and a good garden sprayer.

Let’s take a closer look at how long neem oil lasts and go over some storage and usage tips.

Does neem oil cause skin irritation?

Neem oil is both safe and effective. Someone with sensitive skin or a skin disease like eczema may experience an unpleasant reaction.

Start with a little, diluted amount of neem oil on a small region of your skin away from your face if this is your first time using it. If you notice redness or itching, dilute the oil further or stop using it altogether.

An allergic reaction may manifest itself as hives, a severe rash, or difficulty breathing. If your symptoms persist, stop using neem oil immediately and see a doctor.

Neem oil is a strong oil that should not be used by youngsters. Consult your doctor before using neem oil on a child.

Because no studies have been done to determine whether neem oil is safe to use during pregnancy or nursing, it’s advised to avoid it.

Do you clean your plants with neem oil?

I use neem oil in my garden on a regular basis because it is a potent yet harmless natural insecticide. It will coat garden pests in a thin film of oil and disturb their biological and hormonal processes, resulting in reproductive problems and death.

However, neem oil is an oily product that will attach to the leaves, flowers, and fruit of your favorite garden plants once sprayed, giving them a brief gloss.

I wasn’t sure if this was okay when I first started gardening. Is it safe for me to eat vegetables that have been sprayed with neem oil? Was it necessary for me to first rinse the plants with water?

Plants that have been sprayed with neem oil do not need to be rinsed, but fruit collected within a week of the treatment should be washed thoroughly with soapy water. Neem oil will dry in a few hours, but its insecticidal properties will fully degrade within 2-5 days of application.

When using neem oil to spray your plants, exercise caution. Neem oil can damage or even kill otherwise healthy plants if sprayed at the wrong time or before the arrival of harsh weather conditions, leaving behind charred, decomposing plant material.

However, if used correctly, neem oil is a wonderful natural pesticide that will rid your garden of the worst pests while allowing you to continue growing healthy, organic vegetables.