Grubs in Compost – Are They Good or Bad?

You might be alarmed to find grubs growing in your compost. Stay calm, because you probably have nothing to worry about. Most likely, the grubs are doing you a favor by consuming your organic matter and leaving you various nutrients in your compost.  

In the right amounts, grubs can be beneficial to your compost. Grubs include beetle larvae like the June beetle which can be harmful to your compost in excess populations so you need to screen them from your compost. Other larvae include the green fruit beetle which only eats rotting fruit so you do not have to worry about it.

Are grubs good for compost?

You have probably discovered C-shaped white grubs that are 1-2 inches long in your compost pile which brings you to the question of whether the grubs are good for your compost. The grubs might be a startling sight and they are most likely the larvae of a green June beetle or the bumble flower beetles. Do not be startled because they are good for your compost.

Grubs in Compost – Are They Good or Bad?

The grubs consume rotting organic material. They break down the cellulose in plant material inside their intestinal tracts. This improves the content of compost by making it usable.  

Be careful, however, if you notice brown larvae. It is associated with the brown June beetle larvae that eat plant roots, thus damaging plants. I, therefore recommend that you scrutinize your compost to distinguish white larvae from brown larvae.

Benefits of grubs in compost

  1. Grubs feed on organic matter meaning that they help break down the elements of your compost much faster than they would on their own.
  2. They produce waste known as castings which improve your compost’s nutrient content.
  3. Their burrowing helps aerate the compost which hastens the process of composting. Therefore, if you notice that your compost is not breaking down fast enough, adding some grub will be a great idea.
  4. Adding grubs helps break down manure, and reduces manure’s odor and the chance of disease in areas with animal manure.

How to get rid of white grubs in compost bin

Although grubs are a valuable asset, they have the potential to become a nuisance in large quantities or when they become adults. A population surge may cause physical damage, therefore; you need to control the white grubs in your compost before they become a nuisance.

Grubs in Compost – Are They Good or Bad?

You may choose natural methods to get rid of the grubs or use chemical grub control products. Below are the tips for the option you choose to get rid of grubs from your composting bins.

Natural methods of getting rid of grubs

If you want to get rid of grubs in your compost but hate using pesticides, you can use natural methods to get rid of them.

Here are some natural tips for getting rid of grubs.

  1. You can use earth-friendly nematodes that find and kill grubs. They come in a sponge that you soak in water and put in a spray bottle which you use to spray into your compost. The nematodes multiply over time and kill grubs.
  2. You can also use neem oil. Mix neem oil in water and spray the affected areas of your compost. This will keep grubs from feeding which will prompt their death.
  3. Use organic fertilizer like Plant Tone to kill the grubs.
  4. You can get rid of grubs by adding brown matter to your compost. Grubs live off green material that has juice like banana peels. A brown matter like hay and dried grass inhibit moisture content, therefore adding them to your compost will dry it out thus taking away the spaces where the grubs can survive.
  5. You can also add lime to your compost to change its chemical composition making it a hostile environment for the grubs.
  6. Place your compost in sealed compost containers. Sealed compost containers keep pests away from your compost.
  7. You can allow your chicken or birds to feed on them.

Using chemical grub control products

Carbaryl and trichlorfon are the two chemicals that are considered curative. They are compounds that kill grubs and are the only options in case of a high number of grubs.

Always wear rubber gloves when applying insecticides for your safety.

Common grubs found in compost heaps

The most common types of grubs found in compost heaps include white grubs, Pepper weevil grubs, and vine weevil grubs.

White Grubs

There are various types of white grubs and properly identifying them is critical because of their differences in damage. They are the immature forms of the well-known May/June beetles, Japanese beetle, and the masked chafer.

They are white with brown heads, six prominent legs, are 1/4″ to over 1 inch long, and their bodies are curved into a C-shape. The hind portion of their abdomen is slightly enlarged and appears darker due to soil particles.

They are distinguished from other similar-looking larvae by two parallel rows of spines on the underside of their last abdominal segment.

Pepper weevil grubs

They are present in the southern parts of the United States. They have white or light-grey bodies and brownish-orange heads. They are small measuring ⅕ inches when fully mature. Unlike white grubs, they are not C-shaped.

Vine weevil grubs

They grow from tinny eggs and hatch into 10mm long C-shaped creatures with cream-colored bodies and brown heads. They are pretty resistant to sprays and I advise you to physically remove them if they present a problem.

You can also drench the compost with a systemic insecticide if the grubs become a problem.

Spotting C-shaped, white, worm-like creatures known as grubs is a common phenomenon. While you might be grossed out by their sight, the grubs can be beneficial to your compost because they consume organic material which hastens the composting process and they pass out castings which increase the nutrients in your compost.

However, you might want to get rid of the grubs when they become problematic. You may choose natural ways such as using lime, neem oil, nematodes, or use chemicals like Carbaryl and trichlorfon to get rid of them.

Sources and References

  1. edu. Sealed compost containers
  2. Carbaryl and trichlorfon
  3. May/June beetles, Japanese beetle, and the masked chafer.
  4. Nematodes

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