Cast a set of small planters

Try this

1. Gear up and work outside. Dry cement is caustic and dusty. Wear rubber gloves, a dust mask, and safety glasses, and mix outdoors.
2. Make molds from what you have. An outer container (a yogurt cup, a cut plastic bottle, a takeout tub) and a smaller inner one for the hollow. Spray both with cooking oil so they release.
3. Mix small batches. Follow the bag’s ratio of mix to water until it looks like thick oatmeal. To tint it, stir a little pigment or dye into the water first.
4. Pour, press, and tap. Fill the outer mold, press the inner one in and weigh it down with stones, then tap the sides to release air bubbles. Push a short straw or dowel through the bottom if you want a drainage hole.
5. Wait, then unmold. Leave them covered for a day or two before popping them out. Let them cure for several weeks before they live outdoors so they don’t crack (Blick Art Materials).
6. Finish and plant. Sand rough rims, seal them if you like, and fill them with cuttings or small succulents.

If it feels hard

• If a pot crumbles, the mix was too wet or it came out too soon. Use a little less water and wait longer.
• If it won’t release, flex or cut away the plastic mold. That is why throwaway containers work best.
• If you would rather skip cement, air-dry clay makes good small pots for dry plants indoors.

The science, briefly

Cement doesn’t dry so much as react. Water combines with the cement in a slow chemical reaction called hydration, which keeps strengthening the pot for weeks. That is why a pot that seems solid the next day still needs time before it faces rain and frost, and why keeping it slightly damp while it cures makes it stronger.

Where to start

• Dyed concrete planters: a step-by-step project from Blick Art Materials, with safety gear and curing times.
• Grow something to put in them: Grow succulents from a single leaf.
• Or cover a plain pot instead: Make a mosaic planter.

Mix, pour, and wait. Then fill a shelf with small gardens.