How to Make a Terrarium

Begin by thoroughly cleaning your glass container with warm soapy water. Rinse well and dry completely to remove any residue that could affect your plants. If your container has a narrow opening, consider using a funnel to help add materials.

Position your container in a stable, well-lit location away from direct sunlight before you start adding materials. This prevents having to move a heavy, completed terrarium later, which could disturb your careful arrangement.

Add a layer of small pebbles or gravel to the bottom of your container, creating a layer approximately 1-2 inches deep. This essential drainage layer creates space for excess water to collect away from the plant roots, preventing root rot.

Take your time to spread the pebbles evenly across the bottom of the container. For containers with narrow openings, use a funnel or create one from paper to guide the pebbles in without making a mess.

Sprinkle a thin layer of activated charcoal (about 1/4 to 1/2 inch) over the drainage layer. This crucial component helps filter the water, keeping it clean and preventing bacterial growth and odors in your closed ecosystem.

Note that activated charcoal is different from regular charcoal – it's specially processed to increase its absorption properties. You can find it at most pet stores, garden centers, or online retailers.

Now add your potting soil, creating a layer deep enough to accommodate your plants' root systems – typically 2-3 inches. Shape the soil to create dimension, perhaps forming small hills or valleys for visual interest.

Use a good quality potting soil appropriate for indoor plants. Avoid garden soil or potting mixes with added fertilizers or moisture-control crystals, as these can create imbalances in your terrarium's ecosystem.

Make small holes in the soil for each plant using your finger or a tool. Gently remove each plant from its nursery pot, carefully loosen the root ball, and place it in the prepared hole. Press the soil firmly but gently around the base of each plant.

For containers with narrow openings, use long tweezers or chopsticks to carefully position plants. Work from the back to the front to avoid disturbing your arrangement as you progress.

Enhance your terrarium's landscape with small decorative elements like colorful stones, pieces of driftwood, or tiny figurines. These additions create points of interest and help tell a visual story within your miniature world.

When choosing decorative elements, consider scale—items should be proportional to your plants and container. Also ensure all decorations are clean and free from chemicals that might harm your plants.

Using a spray bottle, mist your terrarium lightly until the soil is moderately moist but not soaking wet. For closed terrariums, you need less water than you might expect—overwatering is the most common mistake beginners make.

Look for slight condensation on the glass as an indicator of proper moisture levels. If water pools at the bottom in the drainage layer, you've added too much—consider removing the lid temporarily to allow some evaporation.

Place your terrarium in a location with bright, indirect light. Direct sunlight can burn plants and cause excessive heat build-up in a closed container. Rotate your terrarium occasionally for even growth if light comes primarily from one direction.

For closed terrariums, monitor condensation levels. If the glass is constantly heavily fogged, remove the lid temporarily to reduce humidity. For open terrariums, check soil moisture weekly and mist when the top inch of soil feels dry.