Concrete garden spheres add curb appeal or enhance your backyard with whimsical hardscaping. Think of them as a modern interpretation of the classic garden gnome!

This post is sponsored by Quikrete

Nestle these spheres between plants or use them to accent porch steps or the patio. No matter where you put them, they’ll make a great conversation piece.

Here’s how to make your own.


Plastic planters hold the forms in place while the concrete cures. (3 Echoes Content Studio)

Materials

  • 4 hollow half foam balls
  • Hot knife foam cutter
  • Toothpicks
  • Caulk
  • Planter or container filled with dirt
  • Quikrete 5000 Concrete Mix
  • Water
  • Nitrile gloves
  • Eye protection
  • Mixing container
  • Drill with a mixing paddle
  • Garden trowel
  • 120- or 150-grit sandpaper

creating forms for concrete garden spheres using a foam ball and hot knife
A hot knife makes a clean cut in the foam ball. (3 Echoes Content Studio)

Create the Forms

You’ll need two hollow half foam balls for each garden sphere you want to create. I’m making two spheres at a time, so I’ve got four half foam balls. 

First, use a hot knife foam cutter to make a 2- or 3-inch-diameter hole in the tops of two half foam balls. (These will serve as the spheres’ tops, in which you’ll pour the concrete — but we’ll get to that later.) 

Then, set the other two half foam balls in planters or containers filled with dirt to hold them steady. (These will serve as the spheres’ bottoms.) Stick toothpicks into the rims of each bottom half foam ball and apply caulk all along the rims. The toothpicks keep the top foam ball from shifting, while the caulk creates a seal so no concrete mix seeps out. 

Inserting a toothpick into a foam ball
Toothpicks secure the half foams balls together. (3 Echoes Content Studio)

Place the other two half foam balls on top of the bottom half balls, ensuring the toothpicks connect the bottom halves with their tops, all the way around. Wait for the caulk to dry. Most silicone caulk takes 24 hours to dry, but some fast-drying caulks only take one to three hours. 


Trowel mixing concrete in a plastic bucket
Mix Quikrete 5000 Concrete Mix and add water until it’s the consistency of oatmeal. (3 Echoes Content Studio)

Mix the Concrete

When the caulk is dry, you’re ready to mix the concrete. I’m using Quikrete 5000 Concrete Mix because it strengthens quickly. 

Tip: When working with cement-based products, always wear a mask, eye protection and nitrile gloves.

Use a drill with a mixing paddle and follow the bag’s instructions for mixing. 

Your concrete mix should look like oatmeal — if it doesn’t, slowly add more water to get this consistency.


Trowel pouring concrete into a foam ball
A small garden trowel is a perfect size for shoveling the mix into the sphere. (3 Echoes Content Studio)

Fill the Spheres

Once the concrete is thoroughly mixed according to the instructions, scoop it into the forms with a garden trowel until they are full. 

Quikrete 5000 Concrete Mix takes about five days to cure in warm weather (70 degrees Fahrenheit or higher) or seven days in colder weather (50-70 degrees Fahrenheit).


Removing foam from a concrete garden sphere
The top of the sphere where the concrete was poured will be the sphere’s base. (3 Echoes Content Studio

Remove the Foam

After the concrete cures, remove the foam balls. 

Chelsea Lipford Wolf uses a hot knife to remove foam from a concrete garden sphere
Cut the foam vertically with a hot knife — this helps to remove larger pieces of foam at one time. (3 Echoes Content Studio

For easier removal, cut long triangles along the balls with the hot knife to help leverage the form off the concrete sphere.


Chelsea Lipford Wolf sands concrete garden spheres
Rub sandpaper in a circular motion for a smooth finish. (3 Echoes Content Studio

Sand Any Imperfections

Once you remove all the foam, sand the entire sphere with 120- or 150-grit sandpaper for a smooth finish. 

Sealing concrete is always a good idea — it will keep the garden spheres from getting moldy, and it will add a slight sheen. Use Quikrete Acrylic Cure and Seal once the concrete has hardened and the surface sheen has disappeared.

Now, all that’s left to do is decide where you want to show them off in your garden!


Further Reading