Apply Nematodes in Ontario: When to Apply and How It Works

Nematodes are a type of worm that is often used when dealing with lawn pests. When should you apply nematodes in Ontario? Nematodes can be applied when the soil has thawed and when the average daytime temperature reaches 50 degrees Fahrenheit. It’s important to note that timing will vary depending on what part of Ontario you live in, as well as when your last frost date was.

Nematodes are a beneficial insect to have in your garden

Nematodes are a type of worm that can be applied when you have an issue with lawn pests such as grub worms and wireworms. They work by attacking pests when they are still young, when they’re not yet fully developed. Nematodes will attack the pests when they are in their larval stage and kill them before it’s too late. They provide a natural way to manage pest populations without having to resort to chemical pesticides which can be harmful for kids when playing outside or pets.

When should you apply nematodes in ontario

Nematodes should be applied when you first notice the pests in your lawn. This is when they’re most vulnerable and when we know nematodes work best at breaking down their population.

Nematode application will help to manage pest populations when used with other proven methods such as using mulch, compost or weed control products that keep weeds from attracting insect populations.

Nematodes can be applied before the spring season starts, but it is best to wait until after the last frost has occurred 

Wait until after the last frost when applying nematodes before the spring season when you know warmer weather will be upon us.

What does applying nematodes entail and how do they work 

Nematodes work by making their way through the ground and when they find a pest, such as white grubs or cutworms, it will feed on them from the inside.

When nematodes are present in high enough numbers their population is managed, which helps to keep pests under control while limiting environmental impacts like soil compaction and water pollution.

How long will it take for the benefits of nematode application to show up 

It can take as long as two months for the pests to be completely eliminated, but when there is a high concentration of nematodes present it can happen in as early as one week.

Who should use nematodes on their lawns or gardens and who shouldn’t

You shouldn’t use nematodes in your garden if you have a well or septic system which drains to the property. You also won’t want nematodes if you’re not willing to water your lawn when they are applied because it will help them work more quickly and do their job better.

Applying nematodes with watering can

Nematodes are applied with a watering can and when used in conjunction with water, will have the desired effect of killing all pests. You want to make sure that you use nematodes when your lawn or garden has high concentrations of pests which is when they work best and fastest.

Chinch Bugs

If you have chinch bugs, you want to use nematodes when the optimum number of them has been reached. Chinch bugs will not be killed when there is only a small population and this can result in an increase if left unchecked which is why it’s important to keep that population under control.


Grubs are another type of pest that nematodes can be used to kill when a high population has been reached. These pests will create damage when they feed on turf, roots and leaves before burrowing into the soil for safety after which point it becomes difficult or impossible to eradicate them.