Carnivorous Plant Terrarium




I've always liked carnivorous plants but while I successfully grow other plants, I've been pretty good and not keeping the carnivorous ones alive. So, in the spirit of the Halloween season I thought I'd give it another try and make a nice mad scientist style terrarium. 

This time I played twenty questions with some folks in the know and I think I may have figured out at least a couple things I was doing wrong. Either way I'm hoping my hungry little garden will at least last the season and maybe take out a few pests in the process. 

The difficulty in this was more gathering materials than executing the project but I did at least one fun thing that was ind of interesting and I did learn a bit. 

I also ended up writing a second Instructable after learning a lot about carnivorous plant potting soil.

Step 1: Materials

A large glass jar. Any jar should do. I chose one I can close up to actively manage the humidity. 

Potting soil. There are certainly better blends than others and you can increase the happiness of your plants by using the correct mix. I just grabbed some basic potting soil. Again, this was a bad idea. Please see my carnivorous plant potting soil Instructable for a mix that won't kill your plants. 

The plants. I went with a classic Venus Flytrap and an interesting Sundew. Probably could have used at least one more but I'm hoping they'll grow to fill in the spaces and I'm trying to encourage some moss as well. There's always time to add more if it looks too sparse. 


Animal skull. I used a raccoon skull I picked up at the same shop I got my plants from but I have a growing collection of type specimens I've been collecting since childhood and then used extensively working as an archeologist. Best to not use something unusual. A raccoon was the perfect size and you can get them cheap on the internet if you can't otherwise obtain one.  

Not Optional:

Distilled water. Tap water or even bottled water will kill Venus Fly Traps and other bog plants. I'm told rainwater is OK as well and has been good for my orchids but I haven't tried it on this type of plant. Distilled water is inexpensive so there's no reason not to use it. Bottled drinking water often has salt added for flavor and will kill your plants and while chlorine is very bad for them it's not the only thing in tap water that will kill CP's. So setting it out over night won't help in this case. 

Total cost if you go out and buy everything is probably around $40. 

Step 2: Preparing the Skull

I thought it would be fun if the Fly Trap was growing out of the top of the skull. This required a fair bit of carving. 

Caveats here:
I used a Dremel with a cutting wheel. This creates a lot of very fine bone dust and in my case awful smelling smoke.

It is unwise to carve bone in this manor without a respirator. it's not good to inhale the dust and could be potentially dangerous beyond the obvious. I also broke a cutting wheel and sent pieces of it flying. 

You can see from the photos I basically topped the calvarium and then cut out the bottom of the brain case. This was so the plant could grow all the way through rather than restrict the roots and hope the bone would eventually rot through. That can take years. 

The roots are fairly shallow on many bog plants anyway but I also wanted it to be an extension of the soil column. 

Step 3: Soil

I wanted this to be a bog in a jar. So, I didn't add stones or other material in the bottom. Just thought it would look nicer without and I can clearly see the soil water level either way. ...I did throw in most of the bone fragments from cutting the skull. The bone would later be confirmed to be fairly inconsequential and while a layer of gravel can help monitor water levels and a couple other factors it isn't essential. 

I guessed at a balance between having enough growth medium and room up top for a healthy micro climate with room for the plants to grow in that direction as well. 

The soil that came with the Sundew was pretty loose and fell apart quite a bit when I unpotted the plant so I mixed it in with the rest. The fly trap had to be cut out of it's root ball a bit to fit into the skull "planter" and I was careful to set aside the layer with moss growing on it. The roots of both were still pretty much covered in the soil they came in. 

Nothing mysterious here other than my needing a CP friendly potting mix. Here's the link to that once again in case you missed it.

Step 4: Placement and Planting

I simply found decent placement for the plants and arranged them like you might in any other terrarium or container garden. 

I mounded up the soil a bit under the skull and dug a nice hole for the Sundew. 

The soil stays wet so things don't move around all that much. 

Step 5: Initial Watering

The only thing to remember is that even gentle pouring can splatter the inside of your terrarium. No big deal, it wipes off but if you tip it at a slight angle you can pour a gentle stream down the side and avoid the mess. 

You'll also want to do this slowly and give the soil plenty of time to soak up the water. Add too much and it's hard to get back out. You want wet soil but not mud or standing water. Just take your time and pay attention. Many bog plants are capable of living at least partially submerged for short periods of time but it isn't ideal and they will eventually die if left that way. 

Again, resist the urge to use bottled or tap water if you haven't picked up some distilled water. 

Step 6: Enjoy the Awesomeness!

I'm pleased enough with the outcome to already be thinking about other variations and daydream a little about more interesting and exotic bog plants. I've also kind of been interested in a full "vivarium" with both plants and animals and what mad scientist doesn't need a few Poison Dart frogs hanging around? 

Step 7: Update: Re-potting and Dispelling Some Myths

In response to some very helpful advice I decided to re-pot my plants in suitable soil that they can continue to live in. 

There were some very constructive comments and some people were kind enough to PM with concern about the health of my CP's. I'm happy to report planting them in regular potting soil will not kill them quickly. The wrong water and fertilizers will knock them out fairly quickly but the soil itself is a slower death and not at all a death sentence. 

After conferring with some knowledgeable professionals including a couple botanists, a pro grower and a soil science guy I sorted out what constitutes good soil for these plants, what kills them and why. 

After a week(it took forever to find the materials here in the city) waiting in regular potting soil my plants are re-potted and still thriving with no reason to think they'll croak. Death by bad soil can take several months and possibly longer if the soil profile is deep enough for the mineral content to leach to the bottom. Areas with high heat or low humidity where water evaporates quickly will have a much shorter safe window to correct a problem like this. 

You can see the tear down and repotting in the images. So, now they have the things they need to thrive, sun, distilled water, acid soil free of minerals and chemicals and even a few lab pests to eat! 

At this point if anything takes them out it'll be life in a smallish terrarium. Considering an arduino based hydro-thermograph as well, just to really track exactly what's going on in there. 

Planning on setting up another terrarium or two and have the materials on order. 

Thanks to everyone who helped out and shared their helpful comments! 

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    30 Discussions


    5 years ago

    Very beautiful. Do they need direct sunlight. My apartment is pretty dark.

    1 reply

    Reply 5 years ago

    That's a great question. Mine did well in a bright window but it was very bright and got sunlight most of the day.

    This is a great article on the topic from the International Carnivorous Plant Society.


    6 years ago on Step 7

    What did you end up with for your final sol mixture?


    The skull was a nice touch!

    I recently found out that even filtered tap water will also kill flytraps. I had a thriving outdoor carnivorous bog garden when I lived near Seattle (same climate & water as Vancouver) but have killed every carnivore I brought home since moving to north Texas, where we have very hard water. The filter removes chlorine and sulphur, but leaves salt and calcium carbonate behind. The cats throwing the little pots off the windowsill didn't help, either.

    I'm ready to try again, maybe in a terrarium so the winter humidity can be kept high enough to keep the plants happy.

    'The Savage Garden' by Peter D'Amato is a good reference.

    Final note: the old garden got moved to my MIL & FIL yard and is still thriving.


    7 years ago on Introduction

    Nice, Dionaea Dente. Are they very hard to grow, in comparison to Dionaea Muscipula? Im thinking about getting some seeds of them.

    1 reply

    Reply 7 years ago on Introduction

    I don't have enough experience to compare them. These were pretty happy little plants as long as the lid wasn't closed tight for too long. I ended up giving away all of my plants, carnivorous and non. Looking forward to having more sometime soon.


    7 years ago on Introduction

    Awesome! I fancy skulls, bones and everything rusty. This is GREAT!!!


    8 years ago on Introduction

    ive got a carnivorous garden growing in a glass bowl on my window sill. ive got a venus fly trap, a pitcher plant, a sundew and a butterwort. i put some big rocks in the bottom, then sprinkled a container of aquarium charcoal, then regular potting soil and finally a thick layer of moss i had collected off some rocks on the side of the highway. transplanting them wasnt easy because of the water content and lack of sturdy roots but i basically just set each one in recess of the moss. that was 2 months ago and its doing awesome. my sundew has grown about 8 inches vertically and i fed my pitcher plant some earth worms that were in a plant my friend gave me which has made it big and strong.
    some things ive learned:
    ~centipedes can crawl OUT of a venus fly trap
    ~fruit flies are impossible to catch alive (in order to feed them to my lovelies)
    ~spiders arent dumb enough to become bait (but they're still dumb enough to be vacuumed)
    ~pitchers need to be full of water in order to live (almost daily misting)
    ~if you live in vancouver, bc you dont need to buy distilled water because our water is clean and awesome (google it if you dont believe me)
    ~your carnivorous plants will not call you seymour. no matter how many treats you give them...

    Great instructable! AND Great comments! Thanks to all who felt able to pass on knowledge instead of letting us learn the hard way. Kudos. Many of you have slaved over the problems that arose, and found solutions!
    I have always wanted to have a few (yah, I got big dreams! lol) terrariums of CP, but having been living in Toronto,Canada and our very cold winters there, I did't have a real chance to try. Now I am in a milder climate (Vancouver) I have a better chance to give those plants the tender lovin' care and uber sunshine they deserve!
    Now for my big question, I have one window in my room. It faces north, and is continually open. I do not get much light directly in, of course. first thing in the morning, and last light of day hits the sill but the rest is indirect. I assume that it is insufficient for such southern plants. Are there any CP that will be able to flourish in my poor conditions? I'll guess at needing some supplemental light regardless of CP, but was hoping there would be a strain or two that enjoy shady dayz....


    8 years ago on Introduction

    i've successfully kept a nepenthes x ventrata alive in an apothecary jar ($16 at Target) for over 2 years now. When I first set the terrarium up, I used:

    (from bottom to top):
    a 2-in. layer of well-rinsed river rocks
    a sprinkling of activated carbon over the rocks (helps keep the water clean)
    thin layer of spanish moss (NOT the ornamental kind)
    soil mix (1/3 peat moss, 1/3 bark , 1/3 coconut husk and a sprinkling of vermiculite)

    I bought some epiphytes delight fertilizer and poured about 16 oz (2 cups) worth in there when I first set it up, then poured enough water in right below where the spanish moss meets the rocks. I've fed it about 8 oz. twice (YES, TWICE) since I got it and it's getting to the point where I think I'm gonna need a bigger apothecary jar.

    Nepenthes are best in a hanging basket to fully appreciate their pitchers, but unfortunately it's just too dry where I live and the only window I have with enough sun is one that's open all the time (they hate drafts).

    1 reply

    Reply 8 years ago on Introduction

    Wow! That looks great! Thanks for sharing and posting a photo. I'm working on a CP potting soil Instructable right now. Looks like you've had some real success there.


    8 years ago on Introduction

    As was already said, the potting soil will kill the plants. Coconut potting products have some nutrition, and coir is not a substitute for sphagnum peat when it comes to carnivorous plants. Many people have problems with perlite in their mixes as well, but I haven't heard a problem with sand.

    The plants you chose also need lots and lots of light.  They will take full sun which you can't get indoors.  They also need seasonal change which is very hard to duplicate indoors.  You would do better with a tropical, shade tolerant carnivorous plant such as some nepenthes species, and nepenthes growers will actually overwinter their plants in terrarium-like environments to keep the humidity high.

    A closed jar isn't so great, but you could just keep it propped open so meh.  If you keep it near fruit, the gnats will swarm in there and feed the plants.

    I've seen terrariums with carnivorous plants like this one, but I'm a bit dubious about how well they work unless it's only a temporary situation such as overwintering.  I have a hard time keeping houseplants thriving, and my houseplants are pretty common houseplants such as pothos.  I move them outside as soon as I can in the year so they can recover from the winter inside the house.  It's much easier to keep plants alive and thriving outdoors generally.  Terrariums are very easy, but it's best to use plants that are well suited to growing in those conditions.

    I think you could grow carnivorous plants very easily, but definitely research them.  I lose plants, and when I go to figure out why they died, I get very annoyed with myself and the things I did wrong.  I had some gazanias wilt and die this year, and I thought they weren't getting enough water so I watered them more.  Well...  it turns out they were wilting because of overwatering.  Crap.  I thought they required more water than what they did.

    Check out when the best time is to divide your plants.  I suspect the venus fly trap needs to go dormant before division or you might lose both.

    For the record, I think it looks nice like a little art piece, and I think you can create a terrarium with carnivorous plants so long as you pick the right container, the right plant, and the right potting mix.  Research some nepenthes and see which one would work well and then select a container.  Nepenthes require slightly different potting mix than other carnivorous plants, so some adjustments would be necessary.

    4 replies

    Actually, that Sundew, which looks like drosrea binata dichotoma (sometimes called a "Staghorn Sundew"), is a pretty good match for the Flytrap in terms of growing conditions.  They only need 1-2 months of dormancy, and those particular plants don't need to die off to the surface like some Sarracenias do. 

    I've had good luck growing both of those species under plain old twin-tube fluorescent shop light fixtures with plain white tubes.  In this case, I might just curl a sheet of white construction paper into a half-pipe and place it behind the jar to reflect light, then use a circular fluorescent tube overhead to light the whole thing, and use a lighting timer to set the photoperiod: 14-16 hours during the growing season, and down to 8-12 hours during dormancy.  If you want to try to use sunlight, I'd take the top off the jar entirely, or you'll cook 'em.

    The best time to divide Flytraps is right as they're coming out of dormancy, but if the environment is stable and correct, they are actually quite resilient little plants.  I've had success during the early and middle parts of the growing season, although I've never tried dividing them when they're thinking about going dormant.


    Putting growing lights on a terrarium sorta defeats the purpose of a terrarium, especially one that was put in a bail jar. That's why I suggested something like a nepenthes for a more permanent terrarium that featured a carnivorous plant and wasn't just for overwintering. It would generally just be easier to maintain depending on the species, and terrariums should be about ease and beauty in my opinion.


    The two main reasons I made the terrarium were that I wanted something fun to look at and having had no luck at all with open planters for CP's in the past as well as being told it might solve some past problems I just went with it.

    I'm fairly certain my main problem before was not using distilled water.


    If it makes you feel better, I lost all my sarracenia because I used perlite infused with Miracle Grow. I hadn't read the package closely enough, and boy did I feel like a dummy. And then I found out that people have problems with perlite generally. Bah.

    However, while the plants were alive and living in a peat/sand mix and did so for a year, I had them in a pot-in-pot set up and collected rain water for them.  They were doing really well and were filling up the container which was when I transplanted them and killed them with the perlite...  If the terrarium doesn't work out, there are other things you can try.  I'd send you a nepenthes cutting to try, but I think it might get confiscated by the department of agriculture.  The nepenthes I have would be too large for a jar, but I have it in a hanging basket outside.  It might actually be hardy where you are.


    8 years ago on Introduction

    Thanks everyone for such insightful and helpful comments. I got a copy of Peter D'Amato's savage garden, a book that was recommended by more than any other and mentioned independently by several. I also dug out my soil science lab manual and did some web research. I'm going to try to sort out both what people here and elsewhere are having success or failure with and see if I can sus out why from a lab standpoint.

    I got peat moss and a chemically inert sand and so far my plants are thriving with visible growth and no apparent issues and seem happy in their jar.

    At the very least I'll update this Instructable soon and possibly make another if there seems to be enough material to warrant it.


    8 years ago on Introduction

    don't know if you know this but bones dust is one of the most dangerous things for you lungs i hope you wore the proper respirator and nit just a dust mask...anyway very cool.

    2 replies

    Reply 8 years ago on Introduction

    Thanks for that. I did wear an actual respirator and made sure to point out the need for it in the Instructable.


    Reply 8 years ago on Introduction

    im not trying to say you don't know what your is obvious you do. but for the safety of those who would want to do this i wanted to impress upon them the dangers involved in cutting bone and that people have died in this process and have gotten ill with diseases similar to silicosis.