Concrete garden spheres are garden accents that can be either decorative or functional and can be made right at home. They can be made hollow, in which case Quikrete concrete is usually the prime ingredient, or they can be made solid, in which case hypertufa concrete should be used since it’s lighter weight.
Either way, many gardeners enjoy the globe shape of concrete garden spheres when placed next to plants and trees. And gardeners can also position hollow spheres with an opening cocked slightly to the side or facing upright in order for the sphere to serve as a planter.
Making the spheres at home is easy and doesn’t cost much money. The process will require a little time to complete, as the concrete needs time to set.
Perhaps most importantly, you will need a place where you have room to work, leave the concrete sphere(s) to set. This should also be a place where you can make a bit of a mess and where you and your work will be mostly sheltered from the elements (especially rain).
Begin by gathering your ingredients and get ready for a hands-on garden are project. The steps below for making solid hypertufa spheres will help you learn how to make concrete garden spheres.
Step 1: Gather Your Materials
Now that you’re ready to begin, gather all your materials at once and be prepared to work uninterrupted, otherwise, the concrete may set. Also, be sure to wear gloves and a dust mask when working with concrete, concrete can irritate the skin so it’s good to wear long sleeves as well. Use sand mounds to hold the balls in place.
Most of the materials you need to make a garden sphere can be found at a chain home improvement store such as Home Depot or Lowe’s. The children’s play balls can usually be found in stores like Target in a wire cage at an end cap in the toy department, and they’ll cost very little. The fiber mesh, which is important for preventing your sphere from cracking, may be found at concrete supply stores.
Shop for the list of things you will need for this project:
- Face mask
- Protective rubber-coated gloves
- Rubber or plastic tub or tray
- Plastic bucket (for mixing concrete)
- Trowel (for mixing concrete)
- Garbage bags
- Children’s play sand
- 1 to 3 rubber children’s play balls
- 1 bag sphagnum moss
- 1 bag perlite
- 1 bag Portland cement (it’s important that it’s cement as we’re making our own hypertufa concrete)
- 1 bottle concrete bonding agent
Step 2: Prepare the children play balls
Set up your shallow plastic tub or tray at a workable height and place some garbage bags over it for protection. This will provide protection from sand and concrete so they will be usable after the project.
Place small mounds of sand on top of the garbage-bagged tray wherever you want to set the play balls. The sand is here to help the balls to stay in place once we start to fill them with concrete. It will make it a lot easier.
Place the ball(s) on each mound of sand so that they won’t roll away. Maybe put some sand on the sides so they will stay in place nicely as we’re going to use them as hypertufa molds.
Use scissors to cut a 2″ diameter hole in each play ball. You should cut right where the plug is so you don’t have that bothering you on the end result.
Step 3: Mix the hypertufa concrete
In your large mixing bucket, combine your dry ingredients. Those are Portland cement, sphagnum moss, and perlite. You should mix all in equal amounts so you will get a proper mixture.
Throw in a handful of fibermesh, this will help for our hypertufa concrete spheres to hold their form and stay strong for years to come.
Mix the dry ingredients thoroughly, breaking up any clumps by (gloved) hand, if necessary. The fibermesh in particular should be broken up as tiny as possible.
Now add equal parts of concrete bonding agent and water, starting with just 1/2 cup of each at a time.
Stir well and continue adding equal parts bonding agent and water until the consistency is right–usually about the feel of thick oatmeal. If you squeeze a handful of the concrete mix into a ball, it should hold a bit of shape. You should also be able to see some visible fibers mixed in.
Step 4: Fill the balls with concrete
Take a handful of the concrete mix and squeeze it into an oblong shape that can fit into the ball’s opening. Then put the handful of concrete mix into the ball’s opening and repeat this several times.
Once you’ve inserted several handfuls, push your hands and fingers down into the mix in the ball to push out air pockets. Repeat now and then as you add more concrete inside the ball. We don’t want any air bubbles as it will not look nice on our end result.
Once you’ve filled up the ball completely with concrete, smooth over the top of the opening so it is rounded to match the surface of the ball.
Now you can leave the filled balls to harden and cure.
Step 5: Finish the spheres
After the concrete has had at least 24 hours to harden completely, put on your gloves and feel the concrete to see if it’s 100% hardened. Depending on the size of the ball and temperature, it might not be ready yet. In that case, let it cure for some more time.
When it is ready, then peel away the rubber balls very delicately. With a gentle surgeon’s touch, use a small tool to lift the lip of the ball and snip to begin gently lifting the rubber away in a spiral pattern. Do it carefully if the concrete feels still soft or the surface is easily damaged, a cutting tool might easily damage it.
Once the ball is successfully removed, a razor blade tool can be used to shave down where the ball opening as if the ball was overfilled. Now this will only work when the concrete is still a little soft, otherwise, you will have to sand it away or use some other kind of tool.
That should be it. Now you have the hypertufa concrete balls ready to adorn the garden. This is quite an easy project and could be done with kids or just for your own fun.
I have also a concrete planters project and like with that, you could also improve with latex paint on the mix. It could give nice light color touch to the end result. Here is a concrete candle holder and concrete leaves as well.