Question

My setup   QUESTION: Hi Chris,

Just recently I decided to get back into my hobby of cultivating carnivorous plants. A few weeks ago, I obtained a 20 gal aquarium to use as a terrarium and purchased several plants. These plants are D. tracyi, Dionaea muscipula (typical), N. mirabilis var. globosa (a lowland species I believe), and an unidentified (I realized after getting it home that it didn't have a tag) species of Pinguicula.

I realize that these plants do not all come from the same climates and will expect somewhat different growing conditions. I have set up a makeshift automatic top watering system for the Nepenthes and am using the tray method with the other three. I have a single tube fluorescent grow light set up over the terrarium on a light timer set for 12 hours. Temperatures are normally around 25 Celcius inside the terrarium at night and about 27 during the day. Humidity is typically around 70% and not below 60%. I mist the Nepenthes whenever I can (I am usually out during the day and gone at weekends). The plants all seem to be growing well. The Nepenthes got some sunburn on its upper leaves, so I placed a tin foil sheet above it so that it is mostly growing in bright shade.

My question is regarding dormancy. I know that D. tracyi and D. muscipula have dormancy requirements and I was wondering if they would need temperature/humidity cues in order to enter that state. I'm not sure if the Pinguicula requires dormancy as I know that there are a huge number of different species.

If the plants do not enter dormancy on their own, should I just leave them be this winter? They all appear to be young plants. I would venture a guess that the flytrap is about three years old with several yearlings growing around it.

I live in Saskatoon, SK, Canada, so the low humidity precludes growing them in the open and the brutal temperatures (as low as -35 Celcius) in the winter preclude outside growing even during dormancy.

Thanks.

ANSWER: Hello Trevor,

D. filiformis var. tracyi can be grown with minimal dormancy. They are from Florida and typically receive very mild winters. You may be able to get away with no, or light dormancy with that Drosera.

Venus Flytraps are considered garden plants that require very high intensity full sun during the growing season, and zone 7 winter down to just above freezing temperatures (in pots anyways). Venus Flytraps that do not have a normal dormancy period of about 3-4 months out of each year tend to die off as annuals.

Plants receive cues from light photoperiod and temperature that inform them of impending winter weather. Without those cues, cold temperatures would take them by surprise and could kill them. Typical cues include recducing the amount of light received each day by one hour  per week until the plants requiring dormancy are receiving 8 or less hours a day. At that point, the plants should be producing hormones to protect them from the cold. Reduce the temperature down to a few degrees over freezing and keep the plants in a few (8 or less) hours of light each day to begin dormancy. Once about 3-4 months have passed, they will require a short period of warming and gradual lengthening of photoperiod until they are back to 12- 16 hours of light per day for the growing season.

Terrariums are generally unnecessary for most carnivorous plants and misting is not required. Some growers have adapted their Venus Flytraps to humidity as low as 15% in a desert. They mainly need time to adapt slowly to gradual humidity shifts downward and plenty of tray water at all times to hydrate. The problem is that N. mirabilis tends to prefer higher humdity and can react rather negatively to low humidity levels.

Most carnivorous plants, like Venus Flytraps and D. filiformis, require much more light to keep up their energy levels during the growing season to carry them through winter. Inadequate light typically causes failure to survive through winter. As an example, I also grow my Venus Flytraps indoors, however; I grow them open pot (45-55% humidity) under 12 40 watt cool white T-12 florescent light tubes about 8-12 inches from their leaves. That produces about 30,000 lumens of intensity (sunlight can generate up to 25,000 to 50,000 lumens). A single tube of the type you have usually produces about 800-1200 lumens maximum. Under 12000 lumens (perhaps 10 times the intensity you have), Venus Flytraps can survive, but just barely. The key is to provide the right conditions that will allow the plants to thrive for decades as they do in nature. You have foil to refract light back in, which does help, but is still limited by the initial light intensity you have.

Nepenthes leaves will often change color under light, so do not worry about it burning under the light you have. Mine receive 18000 lumens only a few inches from florescent tubes and often have orange and reddish tinged leaves.

I can't help you with the Butterwort as there are several different species with different dormancy requirements. Mexican species require much less water for a period of several months during dormancy and North American or European species typically require more typical dormancy with lower temperatures and shorter days.

I think you may need to provide separate growing space for each type of plant so you can grow the tropicals, sub-tropicals and temperates in their own environment and provide them the conditions they require.

I hope the information helps you with your decisions on growing your plants effectively.

Christopher

---------- FOLLOW-UP ----------

QUESTION: Hi Chris,

Thanks so much for the lightning quick response. It seems I was unaware of just how woefully inadequate this light source is for the plants. Upon further research, I discovered that it puts out around 5000 lumens, but still not enough. I do have a desk lamp I could also use which has a fluorescent bulb which could supplement the lighting, but this would probably only be a stop-gap measure.

For some reason, I was under the impression that these plants all required higher humidity than I can provide in the open in my area, but apparently, judging by the historical data I was able to obtain about humidity levels where I live, most would be just fine in the open with the exception of the Nepenthes.

What I am gathering from reading a bit more on the rest of the answers you've given to others is that as long as I gradually transition the plants to conditions outside the terrarium, they should be just fine in the open. I have a south facing window I can grow them in which would probably serve, at any rate better than the artificial light I currently have.

My other problem is that I don't really have anywhere other than the stand in the picture to hang fluorescent lights. I am renting an apartment on a shorter term basis and don't really want to go drilling holes into the underside of the mantle over the fireplace or anything.

Would I be right in thinking that the temperature on the inside of the window (likely just above freezing in -35 C exterior temps) should be okay for dormancy for the flytrap?

The Drosera is producing dew on its leaves, so if I'm reading other articles right, that means it's getting at least some portion of the light it needs? Although I understand that D. filiformis usually produces copious amounts of dew.

Answer
Hi Trevor,

Yes, most of the plants you have would be fine open pot in a window.

In particular, you will want to keep the Nepenthes warm in winter and yes, a cold window will do to keep your Venus Flytrap dormant, cool and with some amount of light over winter.

You might place the light intensive plants in the window you indicated, then add whatever florescent light you have to enhance the window light (in the growing season of course). Window light usually is filtered some by the glass.

Drosera filiformis var. tracyi can survive in slightly less light than Venus Flytraps, however; they can produce some coloration on their tentacles in most of that species hybrids/subspecies, so that can help identify proper light levels if your subspecies develops red coloration. Dew also helps determine proper light in sundews, so large drops of dew on each tentacle is a sign of good light. If the traps are having trouble capturing insects, they probably need more light. Some insects can escape if they are large or strong enough (ants, large flies etc.).