Carnivorous plants are peculiar. They fend for themselves by trapping insects, feeding on their nutrients and that (should) make your job a whole lot easier.
It only works when you know how to set up a carnivorous plant terrarium though. The soil cannot have nutrients because these plants have adapted to survive their life without fertilizer.
Every other type of plant needs a good feed now and then. With carnivorous plants, you need to get them off to a good start in life to get them growing, and then they fend for themselves.
Read on to discover the essentials for setting up a carnivorous plant terrarium, the type to use, the soil it needs, and the types of plants that work in terrariums.
How to set up a carnivorous plant terrarium
Use an open terrarium, add at least 2-inches of sand, crushed rocks, or pea gravel, then layer a sheet of insect mesh netting over it. Use a carnivorous plant soil or make a DIY mix using 1-part sand mixed with 1-part perlite mixed with 2-parts sphagnum moss. Add enough to cover the roots.
1: Only use an open terrarium
An open terrarium is needed for two reasons. One, in a closed environment, insects will be locked out. The plant will not be able to get supplemental nutrients.
The alternative argument to that is to feed live or dead insects to the plant as a natural fertilizer. That can be done, but it will not address the second problem that you will encounter – mold and mildew growth.
In a closed terrarium, springtails would need to be added as they feed on mold, algae, and fungi preventing bacterial infections from reaching levels that harm the roots of plants.
Springtails are not essential in an open terrarium, but they can be used as a protection measure against fungal and bacterial infections.
In a closed terrarium, airflow is drastically reduced, which is why springtails are needed. Some resources go as far as countering that argument by including a terrarium fan.
Adding artificial elements such as terrarium fan kits is not how to set up a carnivorous plant terrarium. Fans are added to a bioactive vivarium. The purpose is different.
- A carnivorous plant terrarium needs to help plants grow.
- A vivarium is a closed environment that grows plants and animals, like reptiles, frogs, and turtles.
They are two different ecosystems, but each is set up in a closed enclosure.
A vivarium supports plants and animals. A terrarium only needs to grow plants.
For that, you need an open terrarium for extra air circulation.
Besides, you will have a hard time adding a portable fan to a tear-shaped glass terrarium or an open-top fishbowl.
2. Getting the base layer right is crucial
All carnivorous plants are bog-dwelling plants. Planting them will be different from any other type of plant you have grown in the past.
Nearly all plants prefer the soil to dry between watering. Soil that is wet for too long poses a risk of root rot. Carnivorous plants are still susceptible to this but the cause of root rot on carnivorous plants is usually bacterial growth.
Anaerobic bacteria grow in wet soil when there is a lack of oxygen. The bacteria feed on the vegetative root growth and that causes the root to rot. Not the standing water. This is the part where adding springtails helps.
To ensure there is adequate oxygenation in the soil, the water needs to drain through the soil to reach the bottom layer. Most terrarium hobbyists refer to this as a drainage layer despite it being illogical because terrariums have no drainage.
Instead of draining, the water is absorbed by sand or gravel that gradually vaporizes, which then keeps the soil moist. As it evaporates from the soil, the humidity increases in the terrarium.
Everything that happens inside the terrarium is reliant on the base layer being absorbent.
The best substrates for moisture absorbance are sand and gravel. Gravel can be crushed up lava rock or pea gravel, or natural stones, and the sand can be any color.
3. The divider layer keeps insects in the soil
The divider layer in a carnivorous plant terrarium serves two purposes. It keeps the soil separate from the gravel base layer and prevents insects from dropping through the substrate divider to hide among the gravel.
An insect mesh netting is a suitable divider material for a carnivorous plant terrarium. There is a wider choice of materials for planting different types of plants in terrariums, such as fir or orchid bark or wood chips, but those only keep the soil above it. Insects can still crawl under it.
In a carnivorous plant terrarium, any insects should be eaten by the plant. You do not want your terrarium to become a nesting habitat for insects laying eggs in soil, or nesting at the base.
That can see your terrarium overrun by nuisance pests like fungus gnats.
As an FYI, fungus gnats start as tiny little white worms. They seek out high humidity environments. The plants’ leaves can feed on the insects, but very few are effective at trapping worms and caterpillars. Instead, the worms feed on the roots and can lead to root rot.
Fungus gnats lay eggs in the soil. Once those hatches, then you get tiny little worms in the soil. Those need to be removed or your terrarium can become overrun with gnats.
4. Getting the soil mix right for carnivorous plants to survive
The best soil for carnivorous plants has little to zero nutrient value. These plants get their nutrients from insects. That is why they are referred to as meat-eating plants.
The only purpose the soil serves is to release vapor from the base layer to increase the humidity inside the terrarium.
You can buy pre-mixed carnivorous plant soil, or you make a DIY mix easily with just a few ingredients. Sphagnum moss, perlite, peat moss or coir, and horticultural sand.
- Dried sphagnum moss can hold up to 10x its weight, slowly releasing it as it dries.
- Peat moss serves a similar purpose, but it is not considered organic because of how difficult it is to mine peat from the bottom of peat bogs. Coir is a sustainable alternative.
- Horticultural sand is a mixture of quartz, sandstone, and granite. Because of the different sizes of particles in horticultural sand, it creates more air pockets in the soil mix making it a good soil aerator.
- Perlite is another amendment that improves soil aeration and boosts drainage capabilities.
To make a DIY potting mix, mix one part sand, one part perlite, and one part peat moss OR coir (washed) with two parts of dried sphagnum moss.
Once mixed, the soil should have a mossy texture. As in, it should feel more like a moss mix than a soil mix.
Add as much of the mix as you need into your terrarium to cover the root depth of your plants.
5. Adding carnivorous plants
The last step to set up a carnivorous plant terrarium is to add them into the enclosure.
Before you do, wash the roots with distilled water or rainwater. A quick and easy way to do this is to remove the plant from its pot and dip its roots in water.
Rainwater or distilled water should always be used on these as you never want to introduce any nutrients into the soil.
The reason to clean the roots is to remove any nutrients and toxins that may be in the soil. Toxins get into the soil from watering with tap water. Nutrients get into the soil when a fertilizer has been used.
When you start your plants, you want them to start with no nutrients. They learn faster to fend for themselves.
For shallow-rooted plants, use a teaspoon or small stick to poke a hole in the sand and a pair of tweezers to push the roots into the hole.
Plants with larger roots need the roots loosened, the soil washed, and then wrapped in sphagnum moss. Dig a well in the soil deep enough to plant the wrapped roots in.
At least an inch spacing should be left between each plant.
The types of plants to choose from
There are numerous species of carnivorous plants, but not all of them are suited to terrariums.
As an example, the only types of carnivorous plants that can survive in water-drenched substrates are aquatic carnivore plants.
Common varieties are some species of bladderworts, and the Waterwheel plant, which is the aquatic variation of the Venus Flytrap plant.
Although these can be grown in terrariums, they are better suited to mini-bogs. A mini-bog setup is generally a deep bucket filled with the same substrate material but kept outdoors.
For an indoor carnivorous plant terrarium, choose from various smaller types of carnivorous plants.
The smallest growing carnivorous plant is the Sundew. With the right setup and proper sundew plant care, these grow to mature heights of around 10-inches, but that can take a few years.
For open-top terrariums (where the plant can continue to grow upwards), consider the Nepenthes Pitcher Plant (Monkey Cups).
Other plant choices include
- Venus Flytrap (Dionaea muscipula)
- Mexican Butterwort (Pinguicula gigantea)
- Cobra Plant (Darlingtonia californica) – the stalks on this grow as long as 33-inches so it will need an open-top terrarium.
Something else to note is that you can get creative and plant your terrarium with succulents and carnivorous plants. This mix of plants can add visual interest with a range of different colors, textures, and shapes.
Frequently Asked Questions related to setting up a carnivorous plant terrarium
Will a carnivorous plant terrarium placed near a bug with plants get rid of the pests?
Carnivorous plants are grown for beauty. Not to control large insect populations. The high moisture and humidity in the enclosure can make existing pest problems worse because they produce pollen that attracts insects. They can only eat so many.
Do carnivorous plants need bugs to survive?
Carnivorous plants do not need insects to survive. Photosynthesis keeps them alive, so they only need light, temperature, humidity, and water to survive. To help them thrive in terrariums, they cannot be fertilized, but they can be fed dead insects, freeze-dried bloodmeal, or similar alternatives.
Marcel runs the place around here. He has a deep passion for houseplants & gardening and is constantly on the lookout for yet another special plant to add to his arsenal of houseplants, succulents & cacti.
Marcel is also the founder of Iseli International Commerce, a sole proprietorship company that publishes a variety of websites and online magazines.