How to make DIY concrete box planters

by Kevin Kelleher 01/13/2025

DIY concrete projects are a great way to increase your home improvement skills, while providing meaningful concrete crafts that could help you stay organized for years to come. However, concrete DIY projects can often seem daunting, but they can be as easy as any other DIY project.

For example, try turning an old cardboard box into a custom DIY concrete planter for your garden. Using just a few basic materials, you can create a durable planter box while getting second use out of an otherwise recycled item. Here is a guide to making your own DIY concrete planter box:

DIY concrete planter tools and supplies

  • 2 Cardboard boxes (one large for the outside of the planter, one smaller box for the inside)
  • Duct tape
  • Cardboard corner protector inserts
  • Concrete mix
  • Mixing bucket
  • Plastic wrap or sheet
  • Safety mask & gloves

How to make your planter

  1. Since cardboard isn’t watertight, you’ll need to reinforce it with duct tape to create a solid concrete mold. Cover the inside of the large box with duct tape and use the protector inserts in the corners. This will help the box keep its shape under pressure.
  2. Cover the outside of the smaller box with duct tape, taking care to completely cover the corners and edges.
  3. Mix the concrete in your bucket by adding the dry material and water. For the correct amount of water, follow the specific instructions included with the concrete. Stir the mixture until it’s smooth, adding more water as necessary.
  4. Fill the larger box about halfway with the concrete mixture.
  5. Press the smaller box into the concrete mixture. Add something heavy to the box, like rocks or sand, to help maintain pressure.
  6. Carefully add more concrete to the sides around the small box until it reaches the top edge of the large box.
  7. Cover the entire box with plastic and allow it to cure for several days in a temperate environment. The curing time for your specific mixture may vary, so consult the instructions for details.
  8. Once the concrete has fully cured, it’s time to remove the boxes. Tear or cut the cardboard down each corner to pull away the sides. It’s optional to remove the inner box, but recommended to help avoid mildew from outdoor use.
  9. With the outer box removed, you’re free to sand away sharp edges if you wish. You might also consider using a concrete sealer.

Now you have your own custom-made DIY concrete planter for your porch or garden. You can repeat this same process with any size or shape of cardboard box. Try adding concrete stain or paint for extra customization to match your personal garden decor.

About the Author
Author

Kevin Kelleher

The thing that sets me aside from other agents is my experience, I started out a young man in construction learning everything from anyone that could teach me so before long I had my own company as a remodeling contractor then specialized in historical renovations by the end I had the pleasure of working on great jobs with great clients for 30 years. For the past 12 years, I have been enjoying the process of assisting my faithful clients with real estate transactions my knowledge of houses has given my clients a huge advantage when viewing properties and what is needed when selling. I have always enjoyed working with people and helping them in probably the largest investment they will make. I hope you will give me the chance to show you that honesty and hard work does pay off in the end whether you're buying or selling.