When To Use Nematodes: Beneficial Nematodes & Your Garden

If you’re facing a pest infestation or you know that one is looming, you might want to use nematodes to help you fight the pests off. Today, we will be talking about nematodes! There are two different types of nematodes – the harmful pest kind that will infest your garden and destroy your plants, and the beneficial kind that will help you control the population of pests in your garden. If you want to know more about these microscopic creatures, read on! First of all, before we can even talk about when to use nematodes, we must first talk about what they are.

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Nema Globe Nematodes Check Price
Pye's ScanMask Beneficial Nematodes Check Price

You or your children may have actually already heard about nematodes before – they were actually featured in an episode of the Nickolodeon cartoon Spongebob Squarepants. There are thousands upon thousands of species of nematodes living with us on the planet. Most of these species are generally harmless, allowing us to coexist with them rather peacefully. In contrast, there are indeed species of nematodes which can cause problems.

Some nematodes are considered to be pests, which can cause disease in pets or wild animals as well as humans. They are also known to cause problems with gardens because they also eat live plants. There are a few parasitic nematodes species, but then there are those that we consider to be beneficial to us humans as well.

What Are Nematodes?

Nematodes are basically roundworms. Yep, roundworms! They’re not exactly true worms, rather they are insects that are multicellular and have bodies that are unsegmented and smooth. The nematodes that you might find snacking on plants are actually so small that you won’t be able to see them with your naked eye – you’re going to need a microscope! If you glance at them through a microscope you will see that the adults of these insects look slender and long, while some others might appear rather pear in shape.

Although you might instinctively think these are the very same roundworms that you might find infecting your body, the fact is they are a different type. The microscopic worms that feed on plants are often found feeding on the plant’s outer surfaces, while some other species might burrow inside the plant’s tissue. Nematodes that dwell in soil are most common, but there are a few species that can damage your precious plants’ roots, foliage, stems, and flowers.

Regardless of where they feed, these microscopic worms can seriously do some damage to crops and plants. They have sharp, pointed mouths that can puncture the walls of a cell. However, the real damage will happen when the nematode then injects their saliva into the cell before sucking out the cell’s contents.

Signs of a Nematode Infestation

If your previously healthy plants and crops begin growing in a distorted way, it may be nematodes. Dead areas on plants as well as swelling are also signs that you may have nematodes. It’s quite difficult to detect microscopic worms, because most of the symptoms are usually vague.

Nematodes spread mostly through moist soil, so as much as possible allow your soil to be well-drained. They may also spread by getting carried in infested soil – so animals, boots, plants, tools and anything that comes into contact with them may also spread them around.

These pest nematodes may also carry some bacterial illnesses and viruses that they can then inject into the plants (in their saliva).

Are There Beneficial Nematodes?

You may have heard of this term being slung around in the past – “beneficial nematodes”. If so, then you may be wondering what they are, and what they do! In fact, it’s these nematodes that we are going to be talking about at length today. Beneficial nematodes offer, as the name might show, numerous benefits. If you are an avid gardening lover, you may have already heard of these before. But if you don’t yet know what beneficial nematodes are, let us tell you all about them! We’ll be talking about what beneficial nematodes are, as well as when to use them in your garden.

What Are Beneficial Nematodes?

Unlike the tiny microscopic nematodes that are considered pests and feed on plants, beneficial nematodes can actually range in size from as small as 1/25th of an inch to as large as several inches in length. These “good” nematodes have translucent bodies that are similarly slender and unsegmented.

Beneficial nematodes have varying roles in the garden. Some of them may be soil-dwelling. These soil dwellers help to break down any organic matter, which is why they are so often used in compost piles. Yep – if you have a compost pile, you might find nematodes to be rather…well, beneficial! In compost piles, these microscopic worms are actually rather easily noticeable. The quarter inch long organic material lovers are easy to spot!

The type of nematodes used in the garden as pest control, however, are still typically tiny and undetectable with the human eye. Although we don’t consider them to be parasitic (at least not to us humans), technically they are still parasites to their prey insects.

Before we get on to talking about when to use these nematodes, let’s talk about the other benefits they may offer.

Other Benefits

The right type of nematode can help to combat a lot of species of pests such as weevils, cutworms, clearwing borers, sod webworms, white grubs, and even chinch bugs. The nematodes attack these insects and kill them. There are two different ways in which they do it – first, they could inject deadly bacteria into these pests. Another way in which nematodes help you to control the population of pests in your garden is by entering the host (pest insect) and parasitizing them, before eventually feeding on them. Pretty brutal, if you ask us.

This is basically why beneficial nematodes are so often used in gardening applications. They break down organic material and keep pests away! Sign us up!

More Relevant Information

If you are thinking about using nematodes in your garden, there are a couple things to know before you go ahead. First, you need to select the correct species of nematodes that are effective against the particular pest you want to fight. This is because certain nematodes are more effective at killing specific pests than others! Therefore, you may want to do your research and read the information about the nematode product very well before you purchase. This way, you don’t mistakenly get the wrong type and end up wasting your money.

Furthermore, it’s important to note that nematodes need humid conditions and moist, warm soil for them to be able to do their jobs correctly. This might be a clue as to when to use nematodes, in fact! Regardless, before you apply the nematodes, make sure you have watered the soil very well. Follow the application instructions for best results!

One more thing – if you’re worried about beneficial nematodes causing harm to you, your family, or your pets, there is no cause for concern. Beneficial nematodes do not harm aquatic animals, mammals, reptiles, birds, or amphibians. They are only interested in pests and compost bins!

When to Use Nematodes

Now we have come to the part where we can talk about when to use the nematodes! We’re sure that this is the part you have all been waiting for! Without further ado…let’s get right to it!

How Much Do I Need?

First of all, different quantities of nematodes will treat different areas, so we want to mention that first. For example, 5 million nematodes are enough for 1600 square feet of space. 10 million will treat 3600 square feet, 50 million will treat 1 acre, 250 million will treat 5 acres, and 500 miliion will treat 10 acres.

How Do I Apply These?

The best way to apply nematodes is to make 2 different applications, with one week to 10 days in between each. This will allow you to stagger the nematodes’ life cycles, ensuring complete coverage. In the case of severe pest infestations, you will need to apply the nematodes every week-10 days until the infestation dies down.

To apply these beneficial little creatures, make sure you have moist soil, then follow the instructions given by the product or package. They are usually applied with a watering can, a sprayer, a backpack/pump sprayer, or even through misting and irrigation systems. Nematodes are basically mixed into water, then the mixture is gently agitated before application. After applying the microscopic worms, you should then lightly water the area.

Note that you should also water the soil every 3 or 4 days afterwards (if there is no rain).

When To Apply

Nematodes need to be applied in the morning or in the evening when the soil is at a temperature of about 42 degrees Fahrenheit to about 95 degrees Fahrenheit. These beneficial nematodes will be effective even up to 95 degrees F, but above that they will not parasitize any prey anymore. Note that a hard freeze won’t kill nematodes or harm them, but if the temperatures are constantly freezing, they will die off.

The best time for when to use nematodes is usually early morning or just before dusk, when the temperatures are relatively cooler and the sun isn’t as bright as it would be at high noon. The reason for this is because UV rays can be harmful to the beneficial nematodes.

Of course, you only really need to apply nematodes if you are facing a pest infestation, or if you know that a certain pest is about to start swarming season. Remember – if you want to kill a specific type of pest, you also need a specific type of nematode!

How Long Can I Keep Nematodes For?

Now that we have answered the question of when you should use nematodes, we now want to talk about how long you can keep them for. Nematodes are shipped to you in trays inside insulating containers. Once they arrive to you, remove the trays from the container immediately and put in the refrigerator.

The simple answer is: use them as soon as you possibly can. Beneficial nematodes are living creatures, so only buy enough to cover 2 applications (the first one, then the 2nd one 7-10 days later) at a time. If you find yourself needing to store them, you can put them in a refrigerator. However, do not keep them for longer than two weeks.

How Long Does It Take For Nematodes To Work?

An obvious question that people may be wondering about is how long it takes nematodes to start working. The answer to this question is… it depends. It can take as little as a week, or it can take three, or it can even take as long as a couple of months. It all depends on how extensive your infestation is, and the conditions of the treated area (i.e. are you regularly watering the soil?).

Examples of Beneficial Nematodes

We can’t exactly give you the specific nematodes for your particular situation, simply because different species work for different pests. However, what we can do is give you a couple of examples of nematode products so that you know what to expect!

Nema Globe Nematodes – No Refrigeration Required Formula

The first product we think is worth mentioning is this new no refrigeration required formula from Nema Globe Nematodes. It conveniently comes with a spray, just to make your life that much easier! This product comes in a 10 million count, meaning it is enough to cover one application for a 3600 square foot area.

Nema Globe’s Nematodes are great for controlling fleas, grubs, and any pests that are soil larval. This makes it ideal for use against white grubs, including the Japanese beetle, the May-June beetle, and Chafer grubs you might find in the soil. What makes this product so great is the fact that it is incredibly easy to use – just mix everything in the sprayer and apply. Unlike other nematode products, this one does not need to be put in the refrigerator, so you don’t need to worry about keeping them. Nevertheless, we still recommend using them as soon as possible! In fact, the company itself states to release these worms immediately.

This product appears to be rather affordable, and is a great way of treating your garden to get rid of any grubs that might be destroying your plants. Note that these microscopic worms die in water if they are in there too long, so make sure that you use them and apply them quickly once you’ve made the water mixture!

Pros and Cons of Nema Globe

✔️Conveniently does not require refrigeration
✔️Comes with a sprayer
✔️Easy to use and apply
❌Some feedback states their sprayers were defective
❌Not sold in Alaska or Hawaii

ScanMask 10 Million Beneficial Nematodes by Dr Pye’s

Another product that we want to mention is this one – Dr. Pye’s ScanMask Beneficial Nematodes. It comes in a 10 million count as well. This particular product does not harm earthworms, praying mantids, lacewings, ladybugs, and any other beneficial insects and creatures that you might actually want in your garden. They also won’t harm humans or animals, and certainly not your plants, too! However, they will seek out and parasitize up to 230 different types of soil-dwelling as well as wood-boring insects.

This product contains Steinemema Feltiae nematodes in particular. They are perfect if you want to get rid of wire worms, Japanese beetles, cut worms, weevils, fungus gnat larvae, white grubs, flea larvae, termites that are subterranean, and even more!

You can use a sprayer with this product in order to make application easier, but you can also simply mix the product directly into the soil and water it afterwards.

The ScanMask product is rather affordable, making it easy to purchase for just about anybody. However, if you know that your area is rather warm, 85 degrees F and up, immediately refrigerate them as soon as you get them.

Pros and Cons of ScanMask 10 Million Beneficial Nematodes by Dr. Pye’s

✔️Easy to apply, completely natural and safe
✔️Effective against up to 230 different types of bugs
✔️Plenty of positive feedback about the product
❌Does not come with a sprayer
❌Requires refrigeration in warmer temperatures above 84 degrees Fahrenheit


The microscopic worms are sometimes a misunderstood creature – mostly because some of them are actually rather harmful. Thankfully, beneficial nematodes exist, and they can help with so many different things! From pest control to composting, these microscopic wonders can work all sorts of magic to help keep your garden and your yard pest-free, and your compost bin working quickly and properly.

We hope that we have shed a bunch of light on nematodes and what they are. Most of all, we hope that we have also answered the question of when to use nematodes! Hopefully, once you try these tiny little things for the first time, you can see just how beneficial they really can be!