Grubs are pests and are an issue many gardeners face when trying to keep their lawns in tip-top condition.
Beetles lay eggs in the late-summer, early-fall, and when those eggs hatch… surprise, you now have grubs!
Grubs are larvae that live in the soil of your grass and survive by eating organic material, such as the roots of your precious lawn, all throughout winter and spring. When these grubs turn into beetles the cycle continues and will continue to do so unless you do something about it.
I’ve been there and let me tell you, grubs are a pain! If you want to know how I, and many other gardeners, combat our grub infestation, then read on!
Disclosure: This post may contain affiliate links. If you shop through the links on YardThyme, we may earn an affiliate's commission from qualifying purchases at no additional cost to you. For more information, read full disclosure here.
- How and Why Are Grubs So Bad?
- How to Tell if You Have Grubs?
- How to Get Rid of Grubs in Lawn
- Fixing the Damage
How and Why Are Grubs So Bad?
At best, a large grub infestation can be the demise of garden beds and vegetable crops, this is definitely not ideal, however is better and easier to deal with than when you have a massive population of grubs in your lawn, then it becomes bad news!
When you have around 10 or more grubs per square foot of lawn, you will definitely notice some significant damage to your grass’s health as they mindlessly munch through the roots below surface level.
Grubs’ main diet consists of grassroots and other organic matter that thrives in the soil and as long as you have grass, you’ll pretty much always experience grubs at some time in your gardening life!
When the grubs work through the roots of your grass they are taking the nutrients away from your lawn which leads to dry and brown grass with a weak root system. Your grass will be easy to pull up and can become crunchy and when it is in this condition, it is really hard to revive.
Moreover, having a grub infestation will be one of the direct causes of animals and birds coming into your garden and digging up your lawn!
The last thing you want on top of a grub issue is an animal pest issue too!
How to Tell if You Have Grubs?
Grubs live below your grass and can be hard to see at first glance, and many times gardeners have difficulty diagnosing a grub problem until they start to question why their grass is struggling so much despite all of the hard work they put in!
There are many ways in which you can find out whether or not you have a grub problem, read on to discover how:
Through Aeration of Garden Beds and Soils
Many gardeners only see the grubs that live in the soil through rotation as this will expose the grubs and will also let you see where they occur in more excess amounts.
Other ways in which gardeners find out about their own sneaky grubs is through investigating the suspicious brown patches on their turf.
The patches are most commonly discovered in late-spring and early-summer when the grubs are at their most active. When in winter, the grubs burrow deeper and are less of a risk as well as harder to find.
If you see the dry patches popping up on your lawn, gently pull on it, and if it easily comes up, it means that you have grubs as the root system of your grass has been compromised through the grubs eating their way through it.
Spongy or Bouncy Grass
If you walk along your grass and notice that a few spots feel bouncy or spongy when stepped on, this is an early tell-tale sign that you have grubs, when it is discovered at this level it is definitely easier to tackle.
Raccoons and Other Animals
The most annoying way to find out that you have grubs is when the raccoons and skunks start to pay you a visit more frequently. This is the worst way in which you can find out as they will relentlessly tear up your lawn in order to find the grubs.
There are many ways in which you can prevent raccoons (and other pests) from digging up your lawn and lucky for you I have an article for that.
How to Get Rid of Grubs in Lawn
Okay so you’ve done your own investigation and you now know you have a grub infestation, now what?
There are many ways in which you can tackle your grub problem and get to the root (haha get it?) of the problem.
When treating grubs, you can either treat them when they’re still young or when they’re adults to prevent them from laying eggs and continuing the cycle.
There are various chemical natural methods that are tried and true in providing you with an effective route to a grub-free (or close to) lawn, all of which I’ve prepared for you!
Apply a Grub Control Pesticide
Insecticides that contain bifenthrin, imidacloprid, or carbaryl are the most effective in killing grubs when your lawn is already established and has a somewhat healthy root system.
Insecticides, such as GrubEx, that contain these active ingredients will kill when they first encounter the grub worms.
In the case of grub insecticides, there are two types: granular and liquid.
For granular insecticides, rake the product evenly across your lawn and water soon after so that it has a chance to seep through and kill the grubs.
In terms of liquid insecticides, create a solution with water in accordance with the label instructions. Spray this solution directly to the affected area, enough so that it can penetrate deep into the soil.
Many great grub killers do the job to a high standard, it is important that you choose the right one as this will ensure you don’t have a repeat infestation as you get right to the issue!
There are many on the market, but these are my personal favorites:
GrubEx is great as it contains all the necessary ingredients for effectively killing the grubs.
It works fast and basically does a really great all-around job in removing the majority of the larvae!
Just like the GrubEx, this insecticide has all the active ingredients for efficient grub killing. Alongside this, it couples as a great pesticide for other insects that are a problem in your garden.
When using a pesticide for grubs, the timing has to be perfect. If your aim is to kill the grubs, then you can use a simple grub killer pesticide and apply it as soon as you see the aftermath effects of them impacting your grass.
If you are after a preventative method then you’ll need to apply grub prevention, such as the BioAdvanced Complete Insect Killer, which is longer-lasting and not only kill grubs but also the beetles that create them, a double whammy!
Apply Beneficial Nematodes
Nematodes are a very popular and natural way that effectively kills grubs in a short time frame. They can be used as a long-term method as well as a short-term spot treatment.
Nematodes are roundworms that kill grubs and those similar through penetrating them and releasing a pathogen that kills them from the inside out.
To use this method, simply mix the nematodes in distilled water and spray them on the affected area. You need to ensure that you keep the water moist when using them.
For long-term preventative methods, reapply the nematodes two weeks later.
Use a Milky Spore Bacteria
Milky spore bacterium introduces disease into your garden that is harmless to your grass but is a great grub killer!
This bacterium is applied as a cloud of fine dust over your turf and is a really effective and long-term method that not only treats the grubs but also the beetles!
The only issue with this method is that it is only effective on Japanese grubs and beetles and sometimes it is really hard to identify which breed you have, so using the milky spore bacterium may not be as effective for your garden.
If you are unsure what type of grub you have you can still use this method as an effort to prevent the Japanese beetles from laying eggs, just to be sure you don’t have too much of an infestation.
Preventative Method: Lawn Care
Lawn care is really important to implement when fighting many insect infestations in your garden.
You’ll notice over time that many insects that give you headaches in your garden are due to improper lawn care!
Creatures such as grubs and earthworms are an indication of poor aeration as loose and dark soils with little rotation are their ideal living environment. By aerating the soil, you introduce fresh light and air into your grass as well as allowing for better rotation of organic waste which disturbs their living environments.
The best aerators are the ones that penetrate deep into the soil to give a deep level of light and air absorption, find my list of the best aerators here!
As grubs feed on organic matter, you need to also focus on dethatching your grass!
Thatch is dead grass and debris that is a layer below your grass that is the perfect source of food for grubs and is one of the main things keeping them thriving in your garden.
To get rid of thatch in your garden you will need a dethatching tool. This will effectively remove the thatch and will also promote a healthy and vibrant-looking lawn!
For other tips on the best lawn care tools, read my article here! It will provide you with the best tools that you can use to create a healthy and beautiful lawn.
Use Fake Lawn
If you’re at the end of your patience with grubs you might want to consider re-turfing your garden with a fake lawn.
This is not the more ideal method; however, it will give you peace of mind as you will never have to face a grub – or another insect issue – in your lawn again.
Synthetic grass requires little to no upkeep and you can enjoy the hassle-free green grass all year long!
Fixing the Damage
Grubs, through eating the roots, create a weak and even dead lawn.
When you notice this, you need to take action in repairing that damage.
- Rake over the dead grass, or pull it up, to expose the soil.
- Reseed that area to grow new grass.
- In areas that aren’t so dead but more or less patchy, just reseed the area and water it.
What is the best time to treat grubs?
The best time for treating grub worms is in late summer or early fall while they are newly hatched and are small and live closer to the surface.
In the spring, the grubs are much larger and deeper, they also don’t feed as heavily as when they are small larvae, therefore, insecticides will prove to be ineffective.
Will grass grow back after grub damage?
The grubs eat the roots of your grass which then hinders the absorption of nutrients.
In the worst-case scenario, your grass will be so badly eaten up that it can actually be peeled up easily, in this situation it is best to reseed the area – once you’ve solved the grub issue – and wait for new healthy grass to sprout.
However, if caught early the roots may still be salvageable and will require some root building fertilizer and proper watering.
Do grubs come back every year?
Pretty much all lawns, in all gardens, have some form of grub every year, unfortunately. The major problem causers are the freshly hatched ones that occur in fall and become less prominent as it approaches spring.
However, as long as the cycle continues, grubs will come back every year, hence it is important to keep on top of your preventative methods such as proper lawn care which will preserve your lawn health in the long run!
Are lawn grubs active in winter?
No. The beetles that lay the eggs that hatch into grubs lay dormant during the winter and many insects don’t actually survive the full winter season due to the uninhabitable temperatures.
If the beetles are dormant in the winter, they then have no chance of laying the eggs, therefore new grubs can’t survive winter.
Unfortunately, grubs still have the ability to survive the winter, they just don’t make significant damage to the grass.
Do grubs die in the winter?
Usually, winter will kill the majority of insects due to the freezing conditions, however, not grubs, they’re too hardcore!
As I said above, grubs can survive the winter seasons. In the winter, the grubs burrow deeper into the soil and live below the frost line, and are therefore protected from the cold.
That being said, in winter they cause the least damage due to being so deep in the soil, hence finding it harder to access the roots that reach higher up.
Can you put down grub killer and grass seed at the same time?
Luckily, there is no active ingredient in grub killer that will impact the growth and health of newly seeded grass.
Grubs cause most of the trauma to your grass in spring, however in fall as well, therefore I would skip on the reseeding during spring and focus on preventing an infestation, and then once your grass is free, or in limited supply, of grubs, I would apply and nurture the grass seeds.
How long does it take for grubs to die after treatment?
Many grub killers indicate that they work in 24 hours, however, for the pesticide to actually take effect and have a noticeable difference it usually spans between 10-14 days.
However, that being said, it also depends on the maturity of the insect, when applied as the grubs are newly hatched and weak, the grub killer will be more effective and work faster, however, more developed grubs are harder to kill.
Grubs are a pest that everyone faces, they can cause irreparable damage to your grass and are overall a major inconvenience!
Killing grubs and preventing them is no easy feat, however, with my tips and tricks hopefully it becomes easier for you to manage and protect the health of your garden.
Let me know what you think, are there any other ways in which grubs can be managed?