Urban Gardening: Artificial Lighting
October 29, 2013 12:14 PM   Subscribe

Last week, I asked MetaFilter about growing a tree indoors. This week, I have a question about aesthetically pleasing artificial lighting solutions.

Last week I asked about growing a tree indoors. Your advice was very helpful and I decided to purchase a lemon tree from Four Winds Growers.

I have the tree in an east-facing window. I'm wondering whether my choice of tree might not have been the wisest as I don't know if the tree is going to get all the light it needs. I'm debating supplementing with additional light. One thing holding me back though is that I have the tree in my bedroom, and most artificial lighting solutions are pretty aesthetically unattractive.

So I'm kicking around the idea of putting a grow light into a fun-looking floor lamp.

Ideally I want something with a flexible head, so that I can get the light really close to the tree and which will allow me to adjust the head as the tree grows.

Examples of the design I have in mind:



I am thinking that I'd probably use CFL lighting for my grow light as it uses less electicity and creates less heat than the alternatives. I'm debating between either a 40W or a 125W CFL bulb. I'm struggling, however, with finding lamps that are rated for either kind of bulb. And so, yet again, I turn to you, hivemind. Please aid me in my quixotic quest to grow a tree in my bedroom.
posted by prunes to Home & Garden (6 answers total) 5 users marked this as a favorite
Response by poster: Not to threadsit, but this setup is basically what I have in mind, although I can't find the exact lamp: http://s177.photobucket.com/user/briedanny2/media/ORCHIDS/DSC00148Small-1.jpg.html

You can see that the bulbs in the lamp aren't designed for it.

If I do something similar, and put 40 W CFL bulbs (150 W incandescent equivalent) into a lamp rated for 15 W CFL / 40 W incandescent bulbs (max I'm seeing right now), am I at risk of burning my house down? If so, what are my best alternatives?
posted by prunes at 2:49 PM on October 29, 2013

Best answer: When you are putting a CFL into a socket, the maximum capacity of the socket corresponds to the actual wattage of the CFL, not the hazy "incandescent equivalent" wattage that is there mostly for marketing purposes. (The number you should care about in terms of light output is the lumens rating, which will vary a bit for different CFLs of the same wattage.) The actual wattage determines the current draw and how much heat the socket will have to deal with, the concern being that if you overload the socket it might catch fire. So yes, you can put a 40w CFL in a 40w rated light fixture, allowing you to throw a lot more light than you could if you were using incandescents.

Same goes for 125w CFLs, though those bulbs are usually humongous and frequently have Mogul rather than Medium bases. I have some 105w CFLs in my room and they are bigger than my head, about a foot long and five inches wide. They have Medium bases that fit into regular light sockets, but that's harder to find the bigger you go. The 125w bulb in your link for instance has a Mogul base, which is substantially larger than that of a regular bulb and requires a special socket not typically available in decorative home lighting fixtures. You can get adapters, but they make the bulb even longer and it's not always a good idea to hang that much weight off a Medium base, which is why those big bulbs are made with Mogul to begin with. Also, running a 125w CFL is like bringing the entire sun into your home. It's not an accent light -- it will substantially brighten the whole room, even in the middle of the day with the curtains pulled back.

For the moment then I'll assume that you'll be using a 40w bulb, since that's about the biggest CFL that will plausibly fit in most light fixtures without looking ridiculous. Whether or not a 40w CFL mounted in the fixtures you are looking at would do anything worthwhile though, I cannot say. I can't see your links as I'm on my phone and copy-pasting bare URLs is a hassle (though if you contact the mods they would probably linkify them for you). I will say though that grow lights usually throw a fairly blue light because that's more like what the sun puts out, and many people find this a bit unpleasant in indoor lighting, especially for accent up-lights such as would normally be used to illuminate a tree. On the plus side that sun-like light is good for seasonal affective disorder, which is what my big CFLs are for. It may look a bit nasty though, and it also may not do your tree much good if it's coming up from the bottom, since most trees are much more photosynthetically active on the tops of their leaves.

So basically this is something that you could do, but I'm not sure you should. If you want your tree to be pretty I'd suggest a nice low-wattage up-light in a warm tone, and if you think it needs a grow light to be happy then I'd install a conventional one above it (perhaps that 125w beast in one of those hanging horizontal reflectors I see on that page) and just run it during the day. I might make the grow light fixture prettier by swapping out its chains for brass ones and painting the outer surface some color that goes with the rest of the room's decor (using high-temperature paint, of course). I bet you'd find that more satisfactory overall.

Good luck!
posted by Scientist at 4:02 PM on October 29, 2013

Best answer: OK, got to my laptop and took a look at the lamps you were thinking about. I didn't quite realize that you weren't talking about up-lights.

That first one is a pretty basic cone-shaped lamp and would probably work fine for your needs although the 40w bulb would probably stick out a bit because the shade is on the smaller side and a 40w CFL is on the bigger side. The 125w bulb would not fit at all and if you forced it to (which would involve removing the lampshade completely and fitting a mogul-to-medium-base adapter in the socket) it would look utterly ridiculous.

The second design wouldn't work with either of the bulbs you have in mind. It's a flat light fixture that requires a funny-shaped flat CFL like this one. It also has a two-pin socket rather than a standard Edison screw as is featured in most US lamps. (Both medium- and mogul-base sockets use variations on the Edison screw design, just in different sizes.) That's not to say that you might not be able to find a similar lamp that takes a more standard bulb, but that particular lamp would not work.

I also note after looking more closely at the bulbs page that the bulbs you are looking at do seem to come in both warm (2700K) and cool (5000K for the 40w, 6400K for the 125w) versions. The 2700k is going to look more like you are probably used to seeing as far as indoor artificial lighting, but I think that the 5000K/6400K versions make plants happier. Chlorophyll absorbs light mostly in blue and red wavelengths and not a lot in between -- it especially absorbs blue wavelengths. A 2700K lamp is not going to put out very much blue light at all, and so your lemon tree might not be able to make very good use of it. Having a bright lamp in a high (cool) color temperature would probably be good for your tree but some people find that it makes homes look sterile, institutional, and uninviting.

If you plan to use the lamp only as a grow light and just want it to look decent when folks are around while sitting there turned off in the corner, then that would probably be fine. However if you want to have a combination accent/grow light, I'm not sure this would really work out for you. I would still go with a dedicated grow light, in a nice-looking fixture if that's what you want, and then put in a couple or two up-lights (like these ones: 1, 2, 3) with a less-bright bulb in a warmer tone.

Cheers! Hope that helps!
posted by Scientist at 5:18 PM on October 29, 2013

Response by poster: Thanks Scientist, that's very helpful. Basically I just don't want an industrial-looking grow light in my bedroom. I don't need the lamp to provide accent lighting. My plan is that I'd run the lamp off a timer. I'd have the timer set to go on while I'm at work. I agree that I probably wouldn't want to be in the room when the lights are on. In terms of specific lamps, what I have in mind is closer to what I linked to in the photobucket picture: something that looks normal to have in one's bedroom when the lamp is off. The two photos I linked to in my initial post was more to give a sense of the style that I had in mind.
posted by prunes at 5:26 PM on October 29, 2013

Hey, if you just want it to look normal when off then that first one would probably do you fine. The 40w bulb might stick out a bit but it wouldn't look awful especially if it were pointed mostly away from where people tend to stand. I would question whether a single 40w incandescent would throw a meaningful amount of light in terms of growing your plant, but that's a different issue and not one that I can answer for you. There are probably some rules of thumb and formulae and such that people in the hydroponics community use to figure that kind of stuff out, and I bet you could look 'em up if you researched around. A single 40w CFL is pretty small beans in terms of grow lights though, I think people tend to use them in groups. Maybe if you just think your tree needs a wee bit more light than its getting from the windows then it'd do the trick.
posted by Scientist at 6:06 PM on October 29, 2013

A 40w CFL lamp will not make a measurable difference for your lemon. CFLs are generally about 75 lumens per watt, which is about 4,000 lumens for that bulb. For a lemon tree to be healthy it needs around 15,000 to 30,000 lumens per square meter. Since you've got a window, I would say that to keep your tree reasonably healthy you need something like the Sunblaze 24, which sadly, is super ugly. Whatever you end up doing, light energy is cumulative so keep any light on as long as possible during the day. You may be able to wring a few more lumens out of LED grow lights, which also have the advantage of being available in a form that will screw into a regular socket (but note the width of the lamps, they are wide). If you want a setup somewhat like your third photo, the LEDs may be your best bet, though possibly still not enough. That's what I would try, though.

If you have a south or southwest exposure somewhere in your house your lemon will do much better. It will also need good humidity, especially over the winter, so a pebble evaporative tray underneath and regular misting is essential. Air movement is good as well. Lemons are incredibly tricky indoors- I work in the Conservatory of Flowers in San Francisco, and we keep all our citrus outside as a general rule, only bringing them into the conservatory to show off for short periods when they are in bud or bloom.

Four Winds has some indoor growing info on their site as well.
posted by oneirodynia at 5:48 PM on October 30, 2013 [1 favorite]

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