For instance, if you choose a woodland theme, you might grow moss, foam flowers, and hepatica. Many of these plants do best in cool, shady conditions. Desert plants, such as cacti and other succulents, do best with brighter light and low humidity levels. Tropical plants, like Tahitian bridal veil and Venus fly traps, like warm and humid conditions.
For example, starfish plants are ideal for terrariums since they only grow to be about 6 inches (15 cm) tall when they’re fully mature. [2] X Research source Some terrarium plants, like club moss, like to spread horizontally. You may need to trim them back to keep them from taking over the entire terrarium. Others, like the false aralia, need to be pruned to prevent them from getting too tall.
For example, a fish tank or an old punch bowl could make a great terrarium for some haworthia, hens and chicks, and mini-cacti. Avoid growing succulents or cacti in containers with tall or curved walls, since these retain more humidity and don’t promote good air flow.
Some plants that do well in more enclosed containers include ferns, begonias, mosses, and ivies. You can even create a fully closed-off environment by growing your plants under a glass cloche or inside a bottle.
Even if the container was never used before, it’s still a good idea to wash it before planting in it. Let it air out for a few days so any water from the washing, as well as manufacturing residue, can evaporate.
You can buy gravel or pebbles at gardening centers or pet supply stores. You could also use crushed pottery, rock chips, or even glass marbles for your drainage layer. This drainage layer is necessary to prevent the soil from becoming soggy in your terrarium, which can lead to problems with mold, bacteria, and root rot.
The charcoal is most effective if it sits on top of the drainage layer. However, if you’re working with a very small container, you can also mix the charcoal into the drainage material. You can purchase activated charcoal from a pet or garden supply store.
Keep the layer of moss thin. You only need enough to completely cover the charcoal layer. You can purchase sheet moss or sphagnum moss at a pet store or home and garden supply center.
The amount of soil you’ll need will vary depending on the size of your terrarium, but you’ll probably need to add a layer at least 1 1⁄2 inches (3. 8 cm) deep to accommodate the roots of your plants. Ideally, all the material you’ve added so far should take up about ¼ of the depth of the container. If your container has a narrow opening, use a large funnel to pour in the soil. [11] X Research source
Before adding any plants, trim off any dead foliage. It’s also a good idea to treat them with a gentle pesticide, such as neem oil or dilute dish soap, to get rid of any hidden bugs or other pests. [13] X Research source Make sure to leave 1–2 inches (2. 5–5. 1 cm) between the plants if possible so that there’s plenty of room for air flow between them. Trim the leaves so that they don’t touch the edges of the terrarium or the other plants, if necessary.
Get imaginative with the decorations if you want. For example, you could add some pretty crystals to create a fairy garden look, or add some sand and seashells for a beach theme.
If you plan to cover your terrarium, wait one day and mist the plants again. Then, once the foliage is completely dry, add the cover.
For example, if you’re growing succulents in a shallow dish, put your terrarium in a sunny window so they can get plenty of light throughout the day. Ferns will probably do better in an area where they get filtered light (such as near a window with gauzy curtains over it). Avoid keeping your terrarium in a spot where it will be exposed to temperature extremes or temperature fluctuations, such as near a heater, air conditioner, or drafty doorway. Put the terrarium in a stable location where it won’t get knocked over easily.
Take care not to over-water your plants. Standing water in a terrarium can quickly lead to rot. If your terrarium is completely closed, it may only need watering every 4-6 months.
You can also prevent larger plants from outgrowing their space by regularly pruning them or pinching back the tips. [20] X Research source
It’s also a good idea to air out your terrarium if you notice a lot of condensation on the walls or mold starting to grow in the soil.
