FlytrapCare Carnivorous Plant Forums

Hello! This is my first post on here and I am glad to be a part of this forum! I have recently started collecting carnivorous plants (in addition to my few, current non carnivorous plants) ATM I have a Nepenthes hybrid (not sure what as its my first, and I got it at a plant nursery that sells it as a "monkey cup" and, it currently only has one developing pitcher, however I believe it is a ventrata or a ventricosa) and a Drosera capensis narrow leaf ordered from cali carnivores.

I had my plants next to the window at college, however now that I am back for summer, my room window faces east and only gets direct sunlight from about 6-7 in the morning, furthermore, the window is under a patio, so it is even more dark in my room. As I arrived yesterday, I realized quickly I needed some artificial lighting, my options are as follows;

- A desk lamp with 4000 lumens, it has a slightly warm white tone. (currently on the plants for the past 2 hours this morning)
- A 24" grow light with red and blue spectrum lighting, however it is cheap and only 12 watts (seems dark by itself)
- A combination of both of the above options (super bright, I feel it would burn the leaves)
- Eventually, once I can empty my fish tank, a 4' light fixture with two T8 florescent bulbs at a total of 64 watts
- I have a clip on desk lamp as well, Im pretty sure it has an 8 watt bulb

The 4000 lumen lamp worked well to grow several plants in a 29 gallon fish tank years ago, including a magnificent amazon sword that grew to the surface of the water. This is my most trusted option however I do not know much about lighting for terrestrial plants lol. Please let me know what you all think, I have only been home since last night so I would like to get this figured out before my plants start feeling sick!

I generally aim for about 2000 lumens per square foot of grow space covered by the light. Its enough to grow healthy and colorful sundews.

Awesome, I have the light a little farther from the plants so they should be getting around that. Is it too much for the nepenthes though?

It may be too bright for some, but ventrata can easily be grown in full sun.

Lumens is a measurement of the light intensity/amount of light/brightness produced as the light leaves the bulb/LED. The further away from the plant the light is, the less the intensity. Lux level (brightness at the plant over an area) and color range of the lights are more important determinants of the light quality for growing plants.

So your 4000 lumen light would provide twice the light to the plants at 4" as it would at 16" if I did the math right.

I have found it very helpful to install a lux meter app on my smartphone. While I do not trust the absolute accuracy of the app's measurements, it does provide a handy way to assess the relative difference between different plants growing environments (read: locations) in my setup.

My comment is an approximation I use to avoid some of the confusion that comes from trying to discuss lighting. There are others in this forum that are far more knowledgeable about lighting than I am. I am sure they can help more. My point is that lumens is not the only thing to consider. Distance from the lumens is also critically important.

Hope this helps.

The way distance affects brightness really depends on the type of light. You'll typically see 1/4 the brightness at double the distance from a bare bulb, but any sort of reflector will help the light maintain brightness with distance, to a certain degree.

Differences between lights is one reason why I don't like to talk about the distance between the light source and the plants, but rather the area covered by the light since that is independent of the type of light source/reflector/etc.

I would take any reading you get from a light meter app with a grain of salt. The light sensors in phones are not designed to provide accurate readings - they just need to be able to tell if it's bright or dim to control automatic screen brightness.

Precisely my point about the phone app. It is helpful in assessing position from the light when comparing (using the same kind of lights), for example, locations on different shelves or different heights on the same shelf even though the absolute accuracy of the measurement may be crap. If the app is measuring, say 1000, and I know the plants have been doing well, then measure say 500 at another spot, then I know that spot might not be the best.

Sorry, but distance does count. Light radiates from it source, so twice as far from the same light generally means 1/4 of the light. Reflectors redirect some of that light that would have been lost, but are not perfect. But if we are talking about the same light source at two different distances, that matters. When you see a light from the side, you are seeing some of the light that didn't make it to the plants. Reflector design can come into play here, admittedly and I believe that grow light fixture design does a better job of directing more light to the plants than light fixtures not specifically created for that purpose. I think we are on basic agreement though. Talking about lighting is complicated, especially for old physicists like me. The common terminology can be be used in different ways which leads to ambiguity.

In some of my grow space, I use mirror tiles at the rear of the shelf to help max the light to the plants. They redirect some of the waste light back to the plant area. Plants on the back of the shelf get better light as a result(and are less likely to get pushed off when I'm rearranging).