How to Create a Thriving Terrarium: A Step-by-Step Guide

A lush, thriving terrarium in a glass jar.

By Carmen De La Paz

Updated on Aug. 02, 2024

Introduction

Bring the beauty of nature indoors with a captivating terrarium. This comprehensive guide provides a step-by-step approach to crafting both open and closed terrariums, ensuring a flourishing miniature ecosystem within your home. Learn essential techniques for layering, planting, and maintaining your terrarium for long-lasting enjoyment. Building a terrarium is a rewarding experience, offering a unique blend of creativity and tranquility.

Two crucial factors determine a successful DIY terrarium: proper layering for drainage and nutrient supply, and moisture control tailored to your chosen plants. Effective layering fosters healthy root growth and prevents diseases. Understanding moisture requirements – whether your plants thrive in humid (closed terrarium) or arid (open terrarium) conditions – is paramount for plant selection and long-term care. This guide will delve into each step, empowering you to cultivate a thriving green sanctuary.

Diagram illustrating the layers of a terrarium: drainage layer, charcoal layer, moss layer, and soil layer.

Tools and Materials

Tools:

• Inexpensive 1-inch chip paint brush
• Small garden shovel
• Water mister
• Watering can
• Wooden chopsticks

Materials:

• Activated charcoal
• Medium-sized stones
• Moss (for closed terrariums)
• Plants suitable for terrarium environment
• Potting soil (and cactus soil for open terrariums)
• Sand
• Small pebbles
• Small stones
• Sphagnum peat moss (for closed terrariums)
• Landscape fabric

Building Your Terrarium: A Step-by-Step Guide

Step 1: Choosing the Right Container

Closed Terrarium: Opt for a container with a lid to trap moisture and provide ample space for soil and drainage layers.

Open Terrarium: Select a container with a wide opening for easy access during planting and maintenance. Consider the size and shape to accommodate your chosen plants.

Step 2: Selecting the Perfect Plants

Closed Terrarium: Choose moisture-loving plants that thrive in high humidity. Consult your local nursery for recommendations. Vary plant heights, leaf shapes, and colors for visual appeal.

Open Terrarium: Opt for plants that prefer dry conditions, such as succulents and cacti. Research or ask your local nursery for suitable varieties. Consider diverse textures and colors for an engaging display.

Step 3: Creating the Drainage Layer

Begin with a half-inch layer of sand, followed by one inch of small to medium pebbles or stones. This crucial drainage base prevents root rot and plant diseases by drawing excess water away from the roots.

Layering sand and pebbles in the bottom of a terrarium for drainage.

Step 4: Adding the Charcoal and Landscape Fabric Layer

Cut landscape fabric to fit the container’s shape and place it over the pebbles. This prevents charcoal from mixing with the drainage layer. Add a layer of activated charcoal on top of the fabric. Charcoal acts as a natural filter, absorbing toxins and promoting a healthy environment. While less crucial for open terrariums, a thin layer of charcoal provides added protection against fungal growth.

Adding a layer of activated charcoal on top of landscape fabric in a terrarium.

Step 5: Incorporating Sphagnum Moss (Closed Terrariums)

For closed terrariums, add a half-inch to one-inch layer of sphagnum peat moss over the charcoal. This moss retains moisture, extending the time between watering.

Adding a layer of sphagnum moss to a closed terrarium.

Step 6: Adding the Soil Layer

Introduce two to three inches of potting soil, forming the foundation for plant growth. Create varied heights and contours for visual interest and to accommodate plants with different moisture needs. For open terrariums, use cactus soil or a blend of potting and cactus soil.

Adding potting soil to the terrarium.

Step 7: Planting Your Terrarium

Carefully arrange and plant your chosen plants, considering their individual needs for light and moisture. Utilize the varying soil heights to position plants strategically.

Planting various small plants in the terrarium.

Step 8: Adding Finishing Touches

Open Terrariums: Arrange small pebbles around plants to enhance visual appeal and prevent soil erosion.

Closed Terrariums: Add small pebbles and living moss for texture and to secure soil layers during watering.

Adding decorative pebbles and moss to the terrarium.

Step 9: Maintaining Your Terrarium

Closed Terrariums:

• Avoid overwatering to prevent root rot and fungal diseases.
• Open the lid for 20-30 minutes monthly for air circulation.
• Avoid direct sunlight to prevent leaf burn.
• Monitor plant growth and adjust accordingly.
• Water every two weeks and mist weekly as needed.

Open Terrariums:

• Place succulents in direct sunlight.
• Allow for plant growth.
• Water weekly or when the soil is dry.

A person misting the plants inside a terrarium.

Step 10: Frequently Asked Questions (FAQs)

Q: What is the lifespan of a terrarium?

A: With proper care, a terrarium can thrive for years, even decades. The average lifespan ranges from four months to two years, often limited by the owner’s dedication to maintenance. Consistent attention to light, temperature, and watering ensures longevity.

Q: Are insects harmful to a terrarium?

A: Insects are often introduced through soil and can play a beneficial role in the terrarium’s ecosystem. Observe for leaf damage, which indicates potentially harmful insects.

Q: How often should I water my terrarium?

A: Watering frequency depends on factors like terrarium size, plant type, and whether it’s open or closed. Closed terrariums require consistent moisture, while open terrariums prefer drier conditions with occasional deep watering. Observe your plants closely for signs of over or underwatering, adjusting your schedule accordingly.