Skip to Content

Using Sand to Prevent Gnats: Organic, Affordable & It Works

You may be surprised to hear that chemicals aren’t the only thing you can use to repel gnats. In fact, there are natural ways to deter these pests and one of them is using sand.

Sand can be used to prevent gnats by layering or mulching the top of potted plants. The sand will act as a barrier, preventing gnats and other insects from venturing into and nesting in the soil of potted plants. Additionally, using decorative sand removes the moist environment they love while beautifying the plant.

This article will show you how to use sand as an effective barrier against gnats. It’s also a great way to keep your potted plants looking nice!

Understanding Gnats

In order to provide an effective means of control, we need to understand what gnats need to survive and what conditions they thrive in.

By knowing these conditions, we can make a better assessment of how to apply sand to effectively control and prevent gnats in potted plants.

What do Gnats need to survive?

  • A gnat infestation thrives in warm conditions and where food and moisture are available.
  • Gnats will also proliferate greatly in temperatures between 75 and 80 degrees Fahrenheit.
  • Gnats love decaying organic matter.
  • Gnats deposit their eggs in the first 2 – 3 inches of soil.
  • They can be found most often indoors, but they can also be found outdoors during the summer months.
  • They have been known to live outdoors year-round.

How can Sand Prevent Gnats?

Using Sand as Mulch

Knowing what gnats love from the list above we can now deduce what we need to do when using sand to help prevent gnats.

When soil, mainly in potted plants is covered or mulched with sand, gnats will have a hard time finding their way to the soil beneath.

Sand can prevent gnats by blocking the top layer of soil that they use to nest and reproduce. Sand also does not hold moisture which gnats love.

As a result, gnats would stay away from plants that are “mulched” with sand. 

Be sure not to use sand that is not too fine because it will hold moisture when the plant is watered which will inevitably invite gnats to nest.

As a side note: The thickness of the laid sand much not be overdone.

Too much sand layered on top of soil would press down the soil beneath causing compaction and bad drainage aeration at the bottom layers of the soil.

On the other hand, applying sand too thin will still present spaces where some gnats may make their way into the soil to lay their eggs. Although it may not be much, there will still be gnats in the soil.

Additionally, plants should be kept in a place that will allow for adequate airflow to that when it is watered the sand does not stay moist or wet for too long.

How do Gnats Damage plants?

Dying houseplant

Potted plants are a favorite breeding ground for gnats. The problem is that the gnat larvae can easily get into your potted plants and damage them. 

Fungus gnats don’t damage plant leaves directly, what they actually do is thrive in the soil laying thousands of eggs that hatch into larvae that munch on root hairs and diminish the soil of essential nutrients.

Another side note is that adult fungus gnats do not harm your plants, but a severe infestation of larvae in the soil can cause the root damage and eventual damage to plants.

Best Sand to Use for Gnats

First and foremost let us look at the different types of sand. There are very different types of sand with different characteristics ranging from color to components.

So briefly we will look at some examples of the types that included: 

  1. Sharp Sand
  2. Coral sand, 
  3. Glass sand, 
  4. Immature sand, 
  5. Gypsum sand, 
  6. Ooid sand

Sand can also be characterized according to its size that including very coarse sand, coarse, medium, and fine-grained

The best sand for mulching in a garden is sharp sand. Why is sharp sand the best for this kind of activity? It is the best for this activity due to its versatility.

Versatility is the ability of the sand, being the center of discussion in this context, to adapt to many different functions or activities.

Sharp sand is a good gardening all-rounder.

Sharp Sand

Sharp sand has a very huge multitude of functions in the garden and is great for mulching. It can be used for things like laying paving and potato slabs, or it can also be mixed with the peat and compost when it is ready for planting.

Glass Sand

This type of sand mainly consists of silicon dioxide and it is the main element

Immature Sand

It is the sand that is composed of the same mineral that it is made up from its parent rocks

Gypsum Sand

The type of sand majorly consists of dehydrated calcium sulfate.

Ooid Sand

They are very rounded pellets that are spheroidal coated in nature grains. It comes from calcium carbonate minerals

The classification of the sand according to size goes just as its names suggest; for instance, fine soil is a type that has a very small size and the texture of it is fine.

How Much Sand to Use for Gnat Prevention

The amount of sand used can have both positive and negative effects on the soil and gnats. 

It is recommended that approximately 1/2 inches of sand, layered evenly over the soil should act as an effective barrier for gnats.

So generally, a 10 inches diameter plant pot would take about 5 to 8 pounds of sand to cover the entire surface of the soil, evenly. 

The measurements do not have to be perfect, but once you can make a part into the sand and see that it’s not too thick of a layer that will be great.

Remember, you want to prevent gnats from nesting and not suffocate the plant.

An additional note when using sand for gnats is to use a sand product that is pleasing to the eye.

Decorative sand is the best option in such a case and will come in a variety of colors. 

All you have to do is choose a sand color that matches your decor.

Mulching with Sand

When used as a mulch for plants, sand creates an attractive contrast between the green of the plants and the white background.

It also helps prevent weeds from growing and protects the soil from water loss and pests. It can also be used as an amendment to help improve soil drainage and aeration in the soil.

The Benefits Of Using Sand As A Mulch

There are so many advantages of using sand as mulch. We are going to cover a few of them that include: they make excellent bases, they have very wonderful accents, it is they are a great choice as compared to grass, they are cheap and they last longer

Using sand for gnats is a cost-effective way of effectively stopping these fruit flies in their tracks.

Mulching soil with sand prevents gnats by covering the top layer of the soil with the dry substrate.

Gnats are attracted to the moist, top layer of soil found in potted plants. It is within the first few centimeters that they lay their eggs and reproduce.

The Takeaway

  • Sand mulch forms a dry layered barrier over moist soil making it difficult for gnats to live and reproduce.
  • Mulching with sand prevents gnats from nesting.
  • Gnats will avoid plants that are mulched with sand.
  • Make sure you don’t apply too much sand.
  • 1/2 inch of sand mulch works best
  • Decorative Sand can be used to beautify the plant
  • Laying sand too thick compresses the soil
  • Laying sand too thin can provide an opening for gnats to move into the soil
  • Sand will not prevent gnats but other insects from nesting in soil