Make a Terrarium to Bring the Outdoors in

Making a terrarium is about as close as you can get to a Zen DIY project. Once you have gathered the proper materials and squared away your plant selections, it’s as simple as layering it all together and watching your mini ecosystem thrive. Here, I’ll walk you through my foolproof process to make a terrarium and cover all the required elements for good filtration, healthy soil, strong root growth and resistance against fungus and disease.

Learn how to make a kokedama ball masterpiece for your home.

Terrarium Tools

• Scissors
• Small garden shovel
• Water mister
• Watering can

Terrarium Materials

• Activated charcoal
• Landscape fabric
• Lidded terrarium
• Living moss
• Plants
• Potting soil
• Sand
• Small/medium pebbles
• Small stones
• Sphagnum peat moss

How to Make a Closed-lid Terrarium

Step 1 Choose a proper container

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Select a lidded container that will trap moisture inside and hold enough soil and drainage layers to support the growth of your plants.

Note: Due to the high moisture level and lack of drainage holes, a closed-lid terrarium has a high risk for root rot, fungus and disease, so drainage layers are extremely important.

Step 2: Select terrarium plants

Choose plants that will thrive in the high-moisture environment of a closed terrarium—consult someone at your local garden center for recommendations.

To give your mini garden plenty of visual interest, select plants that are different in height, leaf shape and color.

Note: Succulents and cactuses are better for open-style terrariums and require different growing conditions.

Step 3: Start with a draining base layer

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Lay a 1/2-in. sand bed into the container. On top of that, add 1-in. layer of small to medium pebbles or small stones. These base layers will pull excess water away from the roots of the plants, helping to prevent decay and disease. If desired, you can add a thicker layer of either material.

Step 4: Lay in landscape fabric and add charcoal

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Activated charcoal will help filter toxins and help keep your plants healthy from disease. To prevent the charcoal from seeping down and mixing into the stones and sand, cut a piece of landscape fabric as close to the shape of your vessel as possible and lay it over the pebbles, then add a ¼-to-½-in. layer of charcoal over the landscape fabric.

Step 5: Add sphagnum peat moss

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Lay in 1/2 to 1 in. of sphagnum peat moss. This layer acts as a barrier to keep the potting mix from sifting into the drainage material.

Step 6: Add potting soil

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Add 2 to 3 in. of potting soil. This will be your terrarium’s thickest layer, where the plants will grow their roots. If desired, vary the height of the soil layer across your terrarium. This will create more visual interest and allow you to emphasize the height differences among your plants.

If you are planning to add any decorative elements, this is the time to think about placement and take advantage of the undulations you’ve made in the soil. High points are good areas to place plants that may need less moisture—water will drain down and dry out faster.

Step 7: Place and plant

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Once you’ve determined your preferred plant placement, add plants.

Note: Plants that thrive in a moist environment tend to grow faster, so be sure to leave them ample space to grow in.

Step 8: Add pebbles and living moss

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Put small pebbles and living moss around the base of your plants—this will add texture and help prevent erosion by holding the layers in place as you water.

Step 9: Maintain your terrarium

Plants in a sealed terrarium seldom need watering. You want moisture in the vessel, but not so much that the roots decay. Observe the environment, and water as you see fit or mist with a light spray.

Open the lid of the terrarium occasionally to let out excess humidity, closing the lid once condensation is gone. Do not put the terrarium in direct sunlight; the glass can act as a magnifier and plant leaves may get burned.

Terrarium Soil Layers

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Water-loving plants grow happily in the moisture of a closed-lid terrarium, but others, such as cactuses and succulents, prefer an arid environment, calling for an open terrarium. Use this guide to build your terrarium’s layers.

Open terrarium

1. Plants
2. Small Decorative Pebbles
3. Soil (Cactus Mix)
4. Activated Charcoal
5. Landscape Fabric
6. Small Rocks
7. Sand

Closed terrarium

1. Plants
2. Small Decorative Pebbles/Living Moss
3. Potting Soil
4. Sphagnum Peat Moss
5. Activated Charcoal
6. Landscape Fabric
7. Small Rocks
8. Sand

Lifespan of a Terrarium

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Quality terrarium care means constant adjustments to the light, the temperature and the watering schedule. On average, terrariums last four months to two years.

Most people give up easily on a terrarium because they aren’t aware of how of care differs for open and closed vessels.