The Ultimate Guide to Pouring Concrete into a Planter Box

The Ultimate Guide to Pouring Concrete into a Planter Box

Are you looking to add a touch of elegance and durability to your garden or patio? Pouring concrete into a planter box is a fantastic way to create a long-lasting and customizable container for your plants. In this comprehensive guide, we will walk you through the step-by-step process of pouring concrete into a planter box, including tips and tricks to ensure a successful project. Whether you’re a seasoned DIY enthusiast or a beginner looking to try your hand at a new project, this guide has everything you need to know to create a beautiful and functional concrete planter box.

Preparing the Planter Box

Before pouring concrete into a planter box, it’s important to properly prepare the box to ensure the longevity of your project. Here are some key steps to take:

Cleaning the Planter Box

Start by thoroughly cleaning the planter box to remove any dirt, debris, or previous plant residue. Use a brush or cloth to scrub the inside of the box and rinse it out with water. Allow the box to dry completely before moving on to the next step.

Sealing the Inside of the Planter Box

To prevent water damage and extend the lifespan of your concrete planter, it’s essential to seal the inside of the box. Apply a waterproof sealant or concrete sealer to the interior walls of the planter box, making sure to cover all surfaces evenly. Let the sealer dry completely before proceeding.

Adding Drainage Holes

Proper drainage is essential for the health of your plants and the durability of your concrete planter. Use a drill to create drainage holes in the bottom of the planter box, ensuring that excess water can easily escape. Be mindful of the size and number of drainage holes to prevent waterlogging and root rot.

By following these steps to prepare your planter box, you can ensure a successful and long-lasting concrete pouring project.

Mixing the Concrete

Gathering materials

Before you begin mixing the concrete, make sure you have all the necessary materials on hand. This includes the concrete mix itself, water, a mixing container, a trowel or mixing tool, and gloves to protect your hands.

Measuring the concrete mix

Once you have gathered all the materials, it’s time to measure out the concrete mix. Follow the instructions on the bag of concrete mix to determine the correct ratio of mix to water. It’s important to measure accurately to ensure the concrete sets properly.

Mixing the concrete

Now that you have all the materials and have measured out the correct ratio of concrete mix to water, it’s time to start mixing. Pour the concrete mix into the mixing container and slowly add water while stirring continuously. Make sure to mix thoroughly until the concrete has a smooth and uniform consistency.

By following these steps for mixing the concrete, you’ll be well on your way to pouring the perfect concrete into your planter box.

Pouring the Concrete

When pouring concrete into a planter box, it is important to follow a few key steps to ensure a successful project.

Layering the bottom of the planter box

Before pouring the concrete, it is essential to layer the bottom of the planter box with a base material such as gravel or sand. This will help to provide proper drainage and prevent the concrete from cracking as it sets. Make sure to spread the base material evenly across the bottom of the planter box to create a solid foundation for the concrete.

Filling the planter box with concrete

Once the base material is in place, it is time to fill the planter box with concrete. Use a shovel or trowel to carefully scoop the concrete into the box, making sure to spread it evenly and fill any gaps or air pockets. It is important to work quickly but carefully to ensure that the concrete sets properly and forms a solid structure.

Smoothing out the surface

After the planter box is filled with concrete, use a trowel or float to smooth out the surface. This will help to create a clean and level finish for your planter box. Make sure to work in small sections, smoothing out the concrete as you go to avoid any bumps or uneven areas. Once the surface is smooth, allow the concrete to set and cure according to the manufacturer’s instructions before adding any plants or soil to the planter box.

Curing and Finishing

After pouring concrete into a planter box, it is crucial to properly cure and finish the concrete to ensure its durability and aesthetics. Here are the steps to follow:

Covering the planter box

To aid in the curing process and prevent the concrete from drying out too quickly, cover the planter box with a plastic sheet or tarp. This will help to retain moisture and promote even curing of the concrete.

Allowing the concrete to cure

Allow the concrete to cure for at least 24-48 hours before removing the formwork. Curing time may vary depending on the type of concrete mix used and the weather conditions. It is important to keep the concrete moist during the curing process to prevent cracking and ensure a strong bond.

Adding finishing touches

Once the concrete has cured, you can add finishing touches to the planter box to enhance its appearance. This can include sanding down any rough edges, applying a sealant to protect the concrete from water damage, or adding decorative elements such as paint or mosaic tiles.

By following these steps for curing and finishing the concrete in your planter box, you can create a durable and visually appealing piece that will enhance your outdoor space for years to come.


In conclusion, pouring concrete into a planter box is a great way to create a durable and long-lasting container for your plants. By following the step-by-step guide outlined in this article, you can ensure that your planter box is properly prepared, the concrete is mixed correctly, and the pouring process goes smoothly. With the right tools and materials, you can easily create a beautiful and functional planter box that will enhance your outdoor space for years to come. So roll up your sleeves, grab your concrete mix, and get ready to transform your garden with a DIY concrete planter box!