Growing plants in a glass bowl, often called a terrarium, is a delightful way to bring greenery indoors. It involves creating a miniature ecosystem within the glass container, focusing on proper layering, plant selection, and careful maintenance.
Understanding the Basics: Open vs. Closed Terrariums
Glass bowls are typically used for open terrariums. Unlike closed terrariums which recycle moisture, open terrariums require more frequent watering and are suitable for plants that prefer lower humidity and good air circulation, such as succulents, cacti, or certain herbs.
Steps to Grow Plants in an Open Glass Bowl
Creating and maintaining a thriving glass bowl garden involves several key steps:
1. Choose Your Glass Bowl
Select a clean glass bowl with a wide opening for easy access and good air flow. Ensure it's large enough to accommodate the chosen plants and layers.
2. Add a Drainage Layer
- Purpose: Although open terrariums have airflow, a drainage layer helps prevent waterlogged soil, which can lead to root rot.
- Materials: Add a layer (about 1-2 inches) of small pebbles, gravel, or LECA (Lightweight Expanded Clay Aggregate) at the bottom of the bowl.
- Optional: You can add a thin layer of horticultural charcoal on top of the drainage layer to help absorb odors and improve drainage further.
3. Add the Substrate Layer
- Purpose: This is where your plants will root and get nutrients.
- Materials: Use a suitable potting mix. For succulents and cacti, use a specialized succulent/cactus mix that drains quickly. For other plants suitable for open terrariums (like certain ferns or air plants with a medium), a general potting mix or a mix with added perlite or sand for drainage works well.
- Amount: Add enough soil to comfortably plant your chosen plants, typically several inches deep depending on the size of the bowl and plant roots. Create contours or hills if desired for aesthetic appeal.
4. Select Appropriate Plants
Choosing the right plants is crucial for success in an open glass bowl. Look for slow-growing, compact varieties that thrive in similar light and watering conditions.
Suitable Plant Types for Open Terrariums:
- Succulents: Echeveria, Sedum, Haworthia, Aloe (small varieties)
- Cacti: Small, slow-growing types (handle with care!)
- Air Plants (Tillandsia): Often placed on decorative elements rather than planted directly in soil, but can add interest.
- Small, Drought-Tolerant Herbs: Thyme, Creeping Rosemary (ensure adequate light).
Avoid plants that require high humidity or grow quickly.
5. Planting Your Plants
- Gently remove plants from their nursery pots.
- Loosen the roots slightly if they are tightly bound.
- Dig small holes in the soil layer for each plant.
- Carefully place the plant in the hole.
- Firm the compost around the base of the plant.
- You can use your hands or you can use chopsticks to gently press the soil around the roots and base of the plant, ensuring good contact and removing air pockets. This technique is especially useful if it's too small to work with your hands.
- Repeat these steps with your remaining plants, arranging them aesthetically in the bowl.
6. Add Decorative Elements (Optional)
After planting, you can add decorative elements like:
- Small pebbles or gravel on the soil surface
- Moss (dried or preserved)
- Small figurines
- Pieces of bark or interesting stones
7. Initial Watering
Water gently after planting. For succulents/cacti, water sparingly. For other plants, water enough to moisten the soil but avoid making it soggy. The glass bowl has no drainage hole, so overwatering is the biggest risk.
8. Ongoing Care
- Light: Place your glass bowl in a location that receives appropriate light for your chosen plants. Most open terrarium plants like bright, indirect light. Avoid direct sunlight, which can scorch plants and overheat the glass.
- Watering: Water sparingly and infrequently. The frequency depends on the plants, the bowl size, and the environment. Check the soil moisture level before watering. For succulents/cacti, let the soil dry out completely between waterings.
- Airflow: The open top provides airflow, which is important for preventing fungal issues.
- Pruning: Trim plants as needed to keep them compact and within the confines of the bowl.
- Cleaning: Occasionally clean the inside of the glass if algae or mineral deposits form.
By following these steps, including carefully firming the soil around your plants using tools like hands or chopsticks, you can successfully grow and enjoy plants in a glass bowl.
