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How to Make Lightweight Cement Planters

Tracy Morris

Some of the most durable planters for gardening are large cement containers that insulate a plant against summer heat and winter freezing. These containers aren't always practical for apartment balconies and rooftops. But by mixing cement with aggregates and organic materials in a hypertufa mixture, you can create a container with all the durability of solid cement, at a fraction of the weight. Because the organics in hypertufa decompose and leave only air behind, the cement resembles alpine tufa rock.

Hypertufa is a lightweight alternative to cement for a planter.
  1. Put on plastic gloves and breathing protection prior to mixing hypertufa. Cement is a caustic building material that can be inhaled as dust and will irritate skin.

  2. Combine one part peat moss, one part perlite and one part cement in a plastic container. This is a simple hypertufa recipe. Exact quantities vary among recipes.

  3. Add water from a garden hose to the mixture until it's as thick as cake batter.

  4. Coat a dowel rod with cooking oil. The oil makes it easier to release the dowel rod from the hypertufa mixture when it hardens. Place the plastic container upside down and insert the dowel rod into the container's drainage hole.

  5. Layer the hypertufa mixture over the plastic container to create a new container made of hypertufa. Cover the container with plastic and allow it to cure and harden for 48 hours. During colder weather, the container may take up to 72 hours.

  6. Remove the dowel rod and carefully pull the plastic container out of the hypertufa planter. Be careful not to break the planter. The cement is at its most brittle at this point. Brush the sides of the hypertufa planter with a wire bristled brush to remove any hard edges. Mist the container and wrap it in plastic again to allow it to cure and harden for another 72 hours.

  7. Unwrap the container and allow it to leech minerals for up to 72 hours by spraying it frequently with water and allowing the water to drain away. This will carry away any minerals that can burn plants placed in the container.

  8. Neutralize the container by soaking it in a vinegar solution. Mix ¼ cup of vinegar per 1 gallon of water. Submerge the planter in the vinegar solution for 30 minutes. Allow the solution to drain away and the container to dry before planting.