I love the industrial-meets-rustic look of concrete planters—and I'm very excited to share the new collection that I've been working on (available soon at the shop). Like all good art projects, the making of pots includes a healthy dose of research and some exciting revelations. And while there are already a lot of really great how-tos out there, my hope is to add a few additional bits of wisdom to the pot-making oeuvre in case you want to try this yourself. (Plus, I'm throwing in a link to Momofuku Milk Bar's cornflake chocolate chip marshmallow cookie recipe—and I swear it's not off-topic You'll see why in just a bit.)
One of the key tenets of DIY concrete-planter-making is that it's "super easy." Well, yes and no. At the absolutely most basic level you'll need: Concrete, water, plastic containers for your molds, non-stick cooking spray, a mixing bucket, eye protection, a ventilation mask, plastic gloves and a stirring stick. There are several other items that will take your concrete-pot-making game from merely amateur to Olde World artisan. Both approaches are great, it just depends on what kind of aesthetic you're going for. I'll cover the extra equipment as I go through the steps, below.
My first, super-important discovery was the availability of Quikrete in handy 10-pound bags. While the little bags aren't as economical, pound for pound, as a traditional 60-pound bag of concrete, they are a lot easier to carry, and they enable small-batch production. But whatever size of bags you go with, be sure to store them somewhere sheltered from the elements. I stashed my first 5-bag purchase in a wheelbarrow under a tarp, but that didn't keep things protected. The wheelbarrow filled with water and the powder morphed into unwieldy concrete blocks. Learn from my mistake! Don't let this happen to you.
Before you mix up your concrete, raid your recycling bin for plastic containers of any shape and size. You'll need two containers (one smaller than the other) to make each pot. Spray the interior of the biggest pot and the exterior of the smaller pot with non-stick cooking spray. Note: Do not use glass or tin. Plastic, especially when you spray it with non-stick cooking spray, works great. Once the concrete is about 80% cured it slips right out of the mold.
Now, here's where the cookies come in: If you discover that concrete pot-making is your new-favorite hobby, you may soon find yourself scanning the grocery store aisles for potential containers. While yogurt pots are an obvious go-to, these pre-packaged single-serve tubs of Frosted Flakes are not only the ideal size, but also very inexpensive. Since I don't normally eat sugar cereal, but I hate wasting food, I had a crazy flash of inspiration and wondered if I could use the Frosted Flakes in cookie batter. Answer: YES. Yes, you can! Enter the famous Momofuku cookie recipe which calls for a very time-intensive step where you coat regular corn flakes with sugar, butter and milk powder and bake the flakes to make cornflake crunch to add to your dough. I can testify that using Frosted Flakes is a great shortcut. Try it and see for yourself!
OK. Back to the DIY.
Initially, I used a plastic bucket and a wooden stick to mix up my concrete. That method wasn't bad, but then I discovered this game-changing video demonstrating how to mix concrete in a wheelbarrow with a common garden hoe. At this point I want to strongly advise that you don eye-protection, a ventilation mask and rubber gloves. Concrete dust is not something that you want to breathe in, and you should also take care to protect your skin. Concrete dust really flies around, even when you're trying to be careful.
Even more game-changing than the idea of mixing concrete in a wheelbarrow with a hoe, was when a friendly contractor friend clued me in to a paddle attachment that works with a 3/8" or 1/2" drill. Wow! Using the paddle ensures that your concrete is very evenly mixed. Plus, it reminds me of making mud pies as a kid. I'd go out in the backyard and stir puddles of mud around with a stick and pretend that I was Julia Child. No joke! I was a little TV show host with a couple of cats as my only audience-members.
Pour the well-mixed concrete into your pots (about half-way full), place the second pot in the center of your poured concrete and weight the smaller pot down with some rocks so the pot doesn't float or lean. Now comes the hard part. You have to wait, and wait and wait for what seems like forever (about 24 hours).
After waiting forever, the big moment finally arrives: slip the pots out of their plastic molds. I like to do this when the concrete is about 80% set. It's nice and firm, but still needs to cure for another day or so before it's completely dry.
Next, and hugely important: drill a hole in the bottom of your pots for drainage so that the roots of your plants don't get water-logged. The thought of drilling a hole in concrete was initially intimidating, but after reading this great article that introduced me to the importance of using a good drill with a saw-hole bit, I plucked up my courage and gave it a shot. The saw-hole bit worked like a charm. Amazing! Once the holes are drilled, use a fine-grit sandpaper and smooth the perimeter of the pot and any other rough edges.
After experimenting a bit, I decided that I prefer to use a sealant on my concrete planters. I use two coats on the interior and exterior. It darkens the concrete just a little bit, and it gives it a low-luster polish that I really like. You can also paint your pots all of kinds of colors, or even add concrete stain into your mix for some pretty spectacular results. But for this DIY I'm embracing the all-natural look.
Now, it's time to start playing around with some plants! In my next post, I'll take my succulents out of their black plastic tubs, put them in my concrete pots, and cover all of the cool stuff I learned about making a 4-part potting soil that's ideal for keeping succulents well-drained, healthy and happy.