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Terrarium Lighting: Choosing a Light Source & Identifying Issues
Terrarium Lighting: Choosing a Light Source & Identifying Issues

Terrarium Lighting: Choosing a Light Source & Identifying Issues

Light, a critical ingredient for plant life, is as important in a terrarium’s ecosystem as it is in any outdoor garden. Understanding its role, as well as how to provide the right amount of light to your indoor green-scape, is vital. 

Let’s delve into how light influences plant growth and health in your terrarium.

light in terrarium

Understanding the Role of Light in a Terrarium

Plants, whether in a field or in a terrarium, need light for photosynthesis—the process by which they convert light energy into chemical energy, enabling them to grow. 

The intensity, duration, and quality of light affect this process. It’s crucial to remember that different types of plants have varied light requirements, and distinguishing between sunlight and artificial light is key to meeting these needs.

The lighting needs of plants can vary significantly based on their natural habitats and growth characteristics. 

terrariums in a mason jar with a rope around the top, set on a wooden floor

Succulents and cacti, for instance, are adapted to intense, direct sunlight found in desert landscapes. They generally need around 12-14 hours of light per day, ideally from a south or west-facing window if relying on natural light. 

On the other hand, tropical plants like ferns and mosses, which naturally grow in the understory of forests, prefer indirect or diffused light. They typically thrive with about 10-12 hours of light daily, with protection from harsh midday sun. 

Carnivorous plants, such as Venus flytraps and pitcher plants, require high light levels akin to their natural boggy habitats—around 12 hours of direct sunlight or a suitable artificial equivalent. 

Meanwhile, foliage plants like ivy or pothos are versatile and can tolerate lower light levels (although they prefer bright, indirect light), making them perfect for rooms with less natural light. 

Knowing the light preferences of these major plant groups can greatly assist in planning and maintaining a healthy, thriving terrarium.

3x terrariums with lights

Best Light Sources for Terrariums

Suitable light sources for terrariums can be natural or artificial. Take a look at the most popular light sources for terrariums.



Sunlight is the most natural and balanced source of light, providing the full spectrum of light wavelengths needed for photosynthesis. 

It’s excellent for terrariums that house plants requiring a lot of light, such as succulents or carnivorous plants. However, sunlight can be unpredictable and sometimes too intense, particularly during the summer months or in hotter climates. 

Direct sunlight can lead to overheating and sunburn in plants, especially in a glass terrarium that can amplify the greenhouse effect. 

When using sunlight, it’s essential to position your terrarium where it can receive adequate but not excessive light, such as near a north-facing window for a gentler light or an east or west-facing window for a bit more intensity.

Fluorescent Lights

Fluorescent Lights

Fluorescent lights, particularly full-spectrum ones, are a popular choice for terrariums due to their ability to cover all light spectra necessary for plants. 

Full-spectrum fluorescent bulbs emulate sunlight’s natural range of wavelengths, supporting the photosynthesis process effectively. They also emit less heat than other types of lights, reducing the risk of overheating your terrarium. 

These lights are excellent for plants requiring medium to high light levels and can be adjusted to provide the correct intensity by moving them closer or further away from the terrarium.

LED Lights

led light terrarium

LED lights are a newer entrant to the horticultural scene but have quickly gained popularity. 

They’re energy-efficient, which makes them cost-effective in the long run, and they have a longer lifespan compared to other light types, making them a sustainable choice. 

The small size of LED lights allows for greater flexibility in positioning, enabling you to provide light exactly where it’s needed. Moreover, specialized plant or grow LED lights are available, which provide the specific light spectrum required for photosynthesis. 

LEDs don’t emit much heat, which reduces the risk of overheating, but they can be more intense than other lighting options, so it’s vital to adjust their distance from the plants to prevent light burn.

Troubleshooting Common Light-Related Issues in Terrariums

In a terrarium, plants rely heavily on the right amount of light to thrive. Anything less than perfect can cause issues with disease and malnourishment for the plants.

If your plants start showing signs of stress, it could be due to improper lighting conditions. For instance, when plants aren’t getting enough light, they may become “leggy” or overly elongated as they reach for more light. 

On the other hand, an excess of light might cause color changes in your plants, such as yellowing leaves or a bleached appearance, indicating that they’re getting sunburned.

image of plant viruses green leaf turning yellow

If you observe these signs and suspect that your terrarium isn’t getting enough light, there are several adjustments you can make. 

Increasing the duration of light exposure each day could help, particularly during the shorter days of winter. Alternatively, you could intensify the light by moving your terrarium closer to the light source or even upgrading your lighting system. 

For example, switching from a standard LED light to a full-spectrum fluorescent or plant-specific LED could provide the necessary light spectrum for photosynthesis.

Conversely, if you suspect your terrarium is getting too much light, causing plant stress, you’ll need to mitigate this. 

Reduce the intensity of the light by moving your terrarium to a location that’s less brightly lit or further away from the current light source. 

Adjusting the duration of light exposure could also help – shorter periods of intense light can prevent sunburn while still providing adequate light for growth. 

If you’re using artificial lights, consider using a timer to automatically regulate the light’s duration, ensuring your plants don’t receive too much light.

Monitor your plants closely for changes as you adjust your lighting strategies to ensure they’re responding well to the new conditions.

In Conclusion…

Light fuels the life-giving process of photosynthesis, making it possible for your terrarium plants to grow and thrive. 

Whether you opt for sunlight, fluorescent lights, or LEDs, what’s most important is that you provide the right amount of light suited to your plants’ needs. 

Keep a keen eye on your terrarium’s light conditions and be ready to adjust as necessary, and you’ll be rewarded with a vibrant, thriving miniature ecosystem.