Question

Sundew   QUESTION: Hello, Christopher. I have recently begun to grow carnivorous plants once more, this time in a 10 gallon terrarium. I started off with one regular Venus flytrap, one American Pitcher plant that is about 2-3 inches tall, two forms of temperate sundews, and one temperate butterwort I purchased from Stauffers of Kissel Hill. At first, everything was going well with all of my plants. However, in the past week or so my sundews and butterworts do not produce any sticky substance anymore. Could this be the due to the fact that my terrarium is indoors and not enough sunlight comes in through my window? I have been in search of an artificial light but have no idea what promotes healthy carnivorous plant growth.

My one sundew does not grow, and the other grows but all of its new branches merely turn black and appear to die.

My butterwort looks a healthy green, but does not produce any sticky substance. However, it is not turning black like my sundews so I am not as worried about it as I am them.

Now I come to the problem I am experiencing. I have recently been searching everywhere for a light that mimics daylight, has the right color temperature, enough lumens, and the correct spectrum of light that my carnivorous plants can use (red through blue). I have heard that incandescent lights are a no-no when cultivating carnivorous plants, as it fries them to a crisp and does not give the correct spectrum for them to utilize.

My main agony over the past week has been finding the correct light for my plants. Do you have any advice on how much lumens I should have, how much color temperature, and what kind of light? (Currently looking at fluorescent tube lights that rest on top of terrarium.)

Thank you for your time in reading this and I hope I was clear enough with my problems! I have includes a photo of my wilting taller sundew for you to study and analyze.

ANSWER: Hello Devon,

Looks like you have the same problems I experienced when I first tried my hand at cultivating temperate carnivorous plants indoors in a terrarium. Terrariums are a no-no as well for most carnivorous plants for many reasons.

1.  First off open the top of the terrarium if it is closed to allow some air in. Open the top only a fraction of an inch every three days until the interior humidity in the terrarium is close to the outside room humidity, usually taking about two weeks of slow, progressive opening. Once that is done or if the entire top is exposed already, then the next step would be:

2.  Get the plants into regular 4-6 inch pots according to plant size and place the pots in trays that can accommodate 1/4 of the pot bottom in clean, mineral free water. Make sure to use only 1/2 sphagnum/ 1/2 perlite mix for potting material and ensure that it is not fertilized. Fertilizers tend to burn and kill off carnivorous plant roots. The Butterwort would actually prefer 1/3 sphagnum peat, 1/3 perlite, 1/3 vermiculite mix but is not too picky. The Butterwort also requires less water so needs only to be watered enough to maintain moistness with barely a fraction of an inch of water in the tray.

3.  All of the plants you have need different light requirements, so placing them all together will only provide one or a few with proper conditions while the others suffer. The Butterwort will be fine under 6000 lumens of light about 6-8 inches from its leaves. The type of light to use for indoor growing would be florescent cool white tubes. All around, those are the best for the cost. The 40 watt T-12 tube shop lights are the ones to use. I just have shelves and desks set up around a room with T-12 shop light fixtures hanging over the plant shelves. You might be able to get away with just placing the Butterwort in the window open pot as the terrarium glass will no longer be in the way, so it might actually get enough natural light.

4.  The other plants need far more light than the Butterwort. Venus Flytraps and Pitcher Plant need the highest end of the light spectrum. You will need to identify the American Pitcher Plant more directly as there are three genera of such plants from different parts of the Americas. There are the Sarracenias (North American), which are diverse and composed of as many as 13 different species or so according to who you ask, Darlingtonia Cobra Plants which are similar to Sarracenias except harder to grow and located in Oregon in North America, and Heliamphora which are South American plants that are also harder to cultivate than Sarracenias in general. In any event, place the Pitcher Plant and Venus Flytrap in the brightest window open pot if you can't get them outside. Both are garden plants, requiring full sun to live past winter each year. If you can find a well lit window and add at least 12000-30000 lumens, 2-5 shop light fixtures with 4-10 tubes, of light over the plants (at least) then you might be able to grow them indoors if you are ready to keep the plants set up for winter dormancy. I do have all of my plants indoors, the Sarracenias and Venus Flytraps growing and flowering well each year, but I have 36000 lumens over them for 16 hours a day in the growing season and I have to undergo a rigorous method of keeping them alive through winter dormancy each year.

The sundew you show in the picture looks like a Drosera intermedia, but is hard to actually place due to the dead leaves. Since you have a second sundew of different species, try to place the species so you can provide it with the best environment. Each sundew, and there are many species in the world, are diverse, and like varying conditions according to species. If both are temperate, you will need to ensure they get plenty of light, similar to what the Venus Flytrap gets, and at least 1/4 the pot bottom in water consistently. Once you have the species sorted out you can try to determine more exact conditions for each plant. For now that generic information should point you on the right path.

Terrariums are a bad idea for temperate carnivorous plants as they are stagnant and full of spores and bacteria, particularly in the drained water in the bottom, cannot provide enough light, promote mold growth, and pump up humidity levels too high to be useful. All of the carnivorous plants you have can tolerate household humidity as low as 15 to 30 percent or lower as long as they have plenty of tray water under the pots. I grow all mine open pot after failing with terrariums for the previous reasons. I understand that terrariums are a great way to feel in control of the plants' environment, but it really keeps the plants from getting what they really need, resulting in dying plants. Only a few species of tropical carnivorous plant require such control of their environment, but those are much harder to grow in general.

Good luck getting those plants set up properly,
Christopher

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

QUESTION: Thanks so much once again for your time in reading and answering.

I set it up in a terrarium because the gardener at the place I bought them said that would be the best thing for them, as a fellow employee had done that with much success with his carnivorous plants (although I don't know if he had all one species, or different).

As for my Venus flytrap and pitcher plant, they are actually doing the best out of all my plants. The sundews started out well, but got drier and started dying off as previously stated. As for the light, right now in Pennsylvania (where I live) it is currently around 80-96 degrees outside on most given days, and the sunlight is very intense. I tried putting my entire terrarium to bask in the sun (I read an article and thought that was the issue with my sundews and butterwort not producing sticky substance), but that made my butterwort shrivel.

In order to address my lighting woes, I am going to purchase two 18" 15 watt GE fluorescent lights from Lowes. One is a sunshine bulb, and one is a daylight bulb. They will mount above my terrarium lid. The daylight bulb actually says it enhances plant growth with red and blue wavelengths. The sunshine has 610 lumens, and 5000k color temperature. The daylight has 700 lumens and 6500k color temperature.

My terrarium is 10 gallons as I think I put earlier. It is 21 inches in length and around 9 and 1/2 inches wide. My only arrangement at this time is to use the terrarium as I have no pots and only have money to buy the two fluorescent lights I mentioned above and their mounts. (Payday hasn't happened for me yet, but I doubt I can get the real expensive ones anyways that have the lumens you were speaking of.)

As for the lid arrangement, I have a mesh wire lid that is basically completely open to the air. And I also have a plastic lid that seals the entire container. I have read of other carnivorous growers saying that having a color temperature between 4k-6k is good, as it is high in blue and red wavelengths. The only thing I worry about is the lumens, as I cannot find anything with very high lumens that would work for my situation. Would the lights I described above be ok, even though they aren't ideal? I've read of people growing these plants with normal fluorescents.

I can do the several-inch-per-day routine for the plastic lid. Once my plants get accommodated to my room, could I just use a metal mesh lid with large holes that used to be for a reptile cage and get rid of the plastic sealing lid? (It wouldn't hinder any air movement in or out of the terrarium is what I'm trying to say.)

Thank you again for taking your time in reading and answering my questions. I have been in quite a frenzy these past couple days trying to figure out a lighting arrangement that would be good for my funds and size of terrarium, as I do not want my plants to die. You have been my most insightful resource thus far and I look forwards to reading your next batch of advice on my current situation.

ANSWER: Hello Devon,

Actually 40 watt shop lights are likely less expensive than the light system your thinking about buying. All those plant lights are just more expensive versions of regular florescent lights. A single 40 watt shop light with twin mount for two tubes only cost me about 15 dollars. One such shop light provides 6000 lumens. I just place a number of them side by side and the collective lumen intensity in the middle of the arrangement is enough for many species of plant. Very cheap when considering that those plant lights I have seen often cost several times as much. In any event, 15 watts is woefully inadequate for anything but an Ivy or maybe a Butterwort. As you noticed, the Butterwort does not like full sun and almost died as a result. It cannot be in the same light levels that the other plants need to survive. The reason why the Sundews and Butterwort are dewless is due to low light levels. The Butterwort needs only a little more light, but probably needs to recuperate from frying first (the ultraviolet light damaged the mucilage and digestive glands on its leaves). When it grows new leaves, it will produce mucilage. The Sundews need far more light before they produce dew. Venus Flytraps and Sarracenias can look like they are doing fine, but come winter, they might not have enough energy to make it through to their next year if they do not have enough light in the growing season. How is the coloration on the new leaves of the Venus Flytraps and Sarracenias? If the new leaves are flat green or only slightly developing coloration, they need more light. Typical Venus Flytraps will develop red inside the leaves and most Sarracenias produce reds, purples, and white sections in their veining and leaf tops. They might be getting just enough to make it for now, but they will require far more light to survive. In any event, even a small, low intensity light unit would be better than nothing until you can get something of higher lumen intensity. Cool White florescent tubes are the regular, cheap tubes and they produce a Kelvin range within acceptable plant growth requirements. All of my plants have been growing under florescents for years, flowering, reproducing etc. It looks like those low cost regular cool white tubes work just as well as any expensive plant lights. The easiest and cheapest way would simply be to get a few cheap pots and just place the Venus Flytrap, Pitcher Plant, and Sundews out on a patio where they can get full sun but be somewhat protected from wind and animals. You may want to provide the plants with partial or indirect sun at first if they have been out of full sun for several weeks as they would have lost some ultraviolet defence and may burn some in full sun at first. Ramp up the intesity of direct sun on a weekly basis until after about two to three weeks have passed and the plants are in full sun, minus the Butterwort, Butterworts can never take full sun and will bake down to a small brown spot. The North American plants can all take the temperatures there just fine. Venus Flytraps and Sarracenias tolerate up to 100-110 degree temperatures so long as they have enough water.

Yes, it is possible to put a bunch of plants in a terrarium and make them survive for a while, but the work involved and possibility of infection and stagnant conditions outweighs any possible benefits (of which I actually can't think of any). With many failed attempts and only a few short lived successes, terrariums are likely the least successful of any method to cultivate North American carnivorous plants. Regular plastic pots are very cheap. I can buy 5 inch pots for 65 cents each from cobraplants.com. That site also has information, similar to my experiences with carnivorous plants, and the guys there are experts on this site as well. Their knowledge and stock are top knotch. Ask them for a second opinion at Sarracenia Northwest.

You can harden the plants off in the terrarium for now as you mentioned earler. In the long run, pots would be the best overall so you can get each species on track.

Remember, if you lose some of the plants, do not become discouraged. There are a lot of myths about growing these plants that will simply kill every carnivorous plant (and most any regular plant) you get. Just treat your carnivorous plants like regular house and garden plants (ensuring to meet their soil, light, and water needs) and they will grow. Your on the way to an easier time of learning about these plants than I had, so just keep absorbing all the information you can.

Christopher

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

QUESTION: Thanks so much for your time once more!

The main problem with my lighting has been that when I go into stores they do not have enough watts, lumens, or the packaging does not even say how much they are. The lighting I just told you about fits into a fixture that holds an 18" tube light. I was planning to get both of them, and have them facing down into my terrarium. And the lumens of all the cool white fluorescents I have seen have very low lumens and color temperature. This is the problem I have been facing, as there are many conflicting opinions upon which light is actually good for them and which is not.

I am growing these as a hobby only (at this point in time). Anyways, every 40 watt shop light is only fitted for 2-4 foot fixtures and fluorescent tube lights. Nowhere have I seen 18" 40 watt light fixtures, which is why I was going to buy these two lights. They have an ok amount of lumens and good color temperature and are bought at Lowes.

Perhaps I merely do not know what to look for with these lights. Could you perhaps put up several links showing which lights I could possibly buy that wouldn't be quite expensive? (Such as the 15$ twin mount with twin tubes). The problem that comes back to face me is that I have not seen any 40 watt light fixtures/tubes anywhere that are 18" that would fit my terrarium.

As for the pots, would the normal ceramic/clay pots that some plants are planted into work for these carnivorous plants? I had heard that one type of pot material would allow harmful substances into the soil through the pot's outer surface over time.

Thanks so much for time in reading this! I eagerly await your advice about the lights, because later today I am heading to Lowes and I want to make sure I get the right lighting that works for my situation. (40 watt doesn't come very small for some reason.)

And one more question. Would a normal (standard) fluorescent bulb work? (The one that resembles a incandescent, but it's fluorescent). I have a reptile light that a bulb-type light would screw into and I could mount above to shine down on the plants. Those come in much higher wattage and it would not be very large at all. And does the light actually have to say on its packaging that it will help plant growth for it to actually help plants grow? That's something that has really given me much stress, as I don't want to buy a normal fluorescent that has good lumens, color temp, and other stuff only to have it that it doesn't help my plants in any way other than lighting them up.

Thanks!

Answer
Hello Devon,

There is really no need to stress about a hobby. Anyways, yes the 40 watt tubes are four feet long. They will not fit your terrarium, they do hang well from shelves and cover a good area. You can use the compact florescent you are talking about, but they need to be cool white. Reptile lights are constructed to maximize a certin level of ultraviolet light with the visible spectrum. Regular cool white florescent is all around the best, but the compacts burn hotter and cover a smaller area, and are lower lumen than the shop light fixtures. I think it would be worth a try to use either compact florescents or regular florescent tubes, in combination with the window light. Remember, the terrarium should only be temporary until you can provide the plants with a cheaper and easier mode of raising them that keeps them all happy. You really do not need to buy many things that you will use only temporarily.

Here is a 10 dollar shop light from Lowes http://www.lowes.com/ProductDisplay?partNumber=245536-58659-NXU-6000&langId=-1&s

You would want to get one that takes T-12 tubes and that has two mounts for two tubes. Also, a brand that has a plug in cord and chains to hang it from along with two inch reflectors along the sides would be best. I settled on a brand that was about 15 dollars each and bought several. The tubes seem expensive, but last at least a year.

Ceramic or clay pots would be fine as would cheap plastic pots.

Christopher