I’ve been wanting some really big fancy planters for next to the front door for some time now but have you seen the prices on large planters?!
That’s ok, because I have a new DIY addiction – concrete planters! So cheap, so chic, so many options.
Although I love the industrial and unassuming look of molded concrete, I wanted to stretch my options by also using vibrant color. For that, these planters are stained and sealed using Unicorn SPiT.
What is Unicorn Spit, you ask? Unicorn SPiT stain is vibrantly colored, non-toxic, and water-based. You can use it as a glaze, a translucent wash, or as an opaque paint. And the best part is that it doesn’t have nasty fumes. It smells like jasmine! Because unicorns smell like jasmine – at least that’s what I believe.
But first, lets get to the creating of these DIY concrete planters…
Materials and Supplies
To make the DIY concrete planters:
- Concrete Mix (You can use cement mix or this high strength concrete mix , or profinish or even countertop mix-each has progressively less rocks in it. I can’t vouch for results from other mixes)
- Containers – You will need 2 containers, 1 for the outer and 1 for the inner mold. I used these plastic planters in various sizes, but these molds also work great and have a modern look to them.
- A trowel or hand shovel to mix the concrete
- A container to mix the concrete in.
- Motor Oil or Concrete Mold Release Spray
To Paint the Concrete Planters:
- Unicorn Spit
- Paint brushes and Water
- Concrete Sealer
Now this is where working with concrete is fun. You can pretty much use anything to make concrete molds. The only constraints are that it needs to be either somewhat flexible (i.e. smooth plastic) or you don’t mind if you have to break it off. I have used plastic planters, old glass jars, plastic buckets, etc.
DIY Concrete Planters Tutorial
Step 1 – Mix the concrete
For a 20 inch wide planter, with a 16 inch insert, I used about 1.5 bags of concrete mix. I used just over a 60lb bag for the 3 brightly painted pots.
In a separate container, mix the concrete with water until the consistency of a thick oatmeal. The more water you add, the smoother the consistency, but your project will also take longer to dry.
Step 2- Prep the Molds
Wipe the inner and outer molds with motor oil or release spray. Pay extra attention to any crevices or corners in the molds.
Place the molds on a level surface. We put our planters on the garage floor and leveled them with wood shims.
Step 3 – Fill the Planter Molds
Fill the bottom of the outer planter to the depth of the bottom of the inner mold. Place your mold inside and fill around the sides evenly with concrete mix.
As you work up, use something to shake the container to get rid of bubbles. We used an electric sander along the sides of the container to vibrate, but you could also bang on it evenly as you work up. The more you vibrate, the less air bubbles you will have in the mix.
Use a board or heavy item to keep the inner mold in place. On smaller pots, we used a spare 2×6. On the larger pots, we clamped around the edges to make sure the inner mold stayed centered and then weighed it down.
Step 4 – Removing from Mold
Once the concrete is set up – i.e. very hard but not dry, you can release from the mold. The longer you wait to dry, the harder it will be to release, but not too early because edges may stick to the mold or become brittle. We removed the inner mold as soon as the concrete was rock hard, and then gave several hours before removing the outer mold. For the largest pots, we waited about 12 hours. We removed the outer mold by turning it over and dumping the planter out upside down.
Tip: If you have any bubbles or pin holes on the exterior of your concrete, you can mix up a small bit of the concrete mix, sift out any rocks and fill in the pin holes with a smooth sponge.
The mix will take about a week to fully dry, depending on humidity, thickness, and how much water you added. The one above is about 4 days after pulling out of the mold so it isn’t fully cured yet. The color will even out and lighten as it cures.
Step 5 – Get Colorful
For all of my planters, I used the Unicorn SPiT as a glaze by diluting it with 5- 10% water. I used the Navajo Jewel, White Ning, and Blue Thunder Colors.
I used Unicorn SPiT in this project specifically because it has a dimensional quality where colors look velvety rather than flat.
Step 6 – Sealing
Concrete is very porous and sealing is required to make your pots last. Since these planters will be used outdoors, I sealed them with a clear acrylic sealer like this one, inside and out.
Instead of paying at least $50 each, the 20-inch planter pots cost about $18 per planter for 2 giant planters.
And they look great to boot!
Have you done any molds with concrete? I would love to hear about your experiences.
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