Bentonite Application Methods

There are 3 main techniques to apply sodium bentonite as a pond sealer. The selection of the technique will depend on the tools available for the bentonite application and the conditions of the pond area.




The blanket method is one of the most common methods for bentonite application. Due to its high effectiveness rate, it is the preferred technique for bentonite application.

To use this method, the pond must be drained. At most, the soil should be lightly humid for this technique to be properly applied.


  1. We start the application by cleaning up the area of any debris, including logs, tree roots, rocks, and any other undesirable material.
  2. Afterward, we proceed to remove a layer of 4 to 6 inches of soil. We will leave them around the area of the pond, as we will use them later.
  3. Only then do we proceed to distribute the bentonite evenly throughout the bottom surface of the pond. The resulting layer is similar to laying a white blanket onto the pond area, thus the name of the method.
  4. For the next step, the 4-6 inches of soil that were previously removed should be carefully laid on top of the bentonite blanket.
  5. Lastly, compact the newly created layers once, spray some water if possible and compact a second time.


The pond will now be ready to be filled. The flow of water to refill the pond should be kept slow and steady to avoid disturbing the newly created layers. While bentonite starts swelling immediately, it achieves full effect 3 to 5 days after the application.

Spreading a big super sack of bentonite using a skid steer



The mixed blanket method creates a very even bottom surface. It is usually used when a blanket is not possible due to climate conditions or lack of the correct tools. When correctly done, it can have a great effectivity. However it does require a bit more work and attention than the blanket method.

To use this method, the pond must be drained. The soil must be dry for this technique to be used.


  1. The application starts with a thorough cleaning of the pond area. Any debris and unwanted material should be removed, leaving the surface as smooth as possible.
  2. For this method, the next step is to distribute the bentonite evenly across the pond area. Using our super sacks, the bentonite distribution is easily done by holding the sacks up with a tractor or forklift and opening the discharge valve at the bottom of the sack.
  3. After distributing the bentonite over the area, disk or till the bentonite in, about 4 to 6 inches into the ground. The goal is to try to create a homogeneous mix of bentonite and soil at the bottom of the pond. We are hoping to achieve a blanket of a bentonite – soil mixture, therefore the name of the method.
  4. Lastly, we need to compact the newly created layers once, spray some water if possible and compact a second time.


This method helps to make the surface smooth and consistent by dragging the soil all along the waterbed.The pond must be filled slowly and steady, attempting to keep the integrity of the soil-bentonite layer that was recently created.

Tilling the soil for mixed blanket Bentonite application



The sprinkle method is the least commonly used method for bentonite application. That’s because due to particle dispersion, it usually requires a higher bentonite per square foot ratio than the other bentonite application methods.


However, the sprinkle method is the one that should be used when the pond cannot be drained. If for any reason it isn’t possible to drain the pond, you can still use bentonite to reduce water seepage and seal water leaks.


It requires the use of granular bentonite, which is still sodium bentonite but pulverized at a different grain size.This helps ensure the bentonite grains reach the bottom of the pond and “filter” themselves into any gaps, holes or crevices at the bottom surface.


Depending on the size of the pond, there are a couple different ways to apply the sprinkle method. When possible a slow and steady approach is taken, slowly depositing the bentonite particles on the surface of the water. When the pond is too big to ensure every corner is sprinkled with bentonite, the application is done with a pneumatic trailer, attempting to get the bentonite evenly over the surface of the water body.

Applying Bentonite with a pneumatic trailer to a large pond with water

Do you need help applying Bentonite?


We offer the complete services to line an repair your pond. We’ll provide the necessary equipment, materials and 50 years of experience sealing ponds.

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sodium bentonite super sackss 3000lbs on a pond

How much bentonite my pond needs?

Bucket Test

The Lonestar Bucket test is a simple guide that will help you to know your pond soil type.

The soil type is key to knowing how much sodium bentonite is needed to create a strong pond seal.

Lonestar Bucket Test