Excellent question, as I too would like to know what to do with the newly germinated White Pine, Concolor Fir and Douglas Fir I have in pots! Hope to hear some answers!

Plain Fluorescent bulbs with cheap ballasts (ballast is what holds the bulbs) on a timer for 16 hours a day is perfect.

You want light 'coverage' over all your seedlings (surface area) so 'that' will ultimately 'decide' how many ballasts you will need.

Dax

P.s. check the current thread (pg 2) about 'sterilizing for cuttings." A link will lead you to "grow lamps".

"I was wondering if a grow light would help them at all. Any ideas?"

Yes is the answer, up to a point anyway. You can have too much of a good thing, but with fluorescent shop lights that's unlikely. They are not very bright. Even if they look bright to your human eye.

Just dont place a HID light too close. A little light meter might be a good investment too.

I might not use artifically long days during the winter(at least not 16 hours long ) because in the spring I think your seedlings will be living outside and then you're exposing them to much shorter days. Might not mater though.

Doesn't matter but helps right now as would heat mats but those really aren't needed unless you're propagating other than potted seedlings.

You two need light for your plants. Fluorescents are recommended. Keep the actual bulbs themselves' a few 2-4 inches from the tops of your seedlings. To find the very most efficient distance you can hold your hand under the lights for 10, 20, 30 - seconds and when it is comfortable to you, it will be comfortable to your plants.

Come next year, keep your seedlings in partial sun/filtered light all year (under a large conifer or deciduous tree is perfect). Otherwise, they'll burn on you. Come the next year, do the same, then they'll be fine on their own and have a gallon's pot or more of a root system and you'll be able to keep them in full sun from then on out.

Dax

RE: "Fluorescents are recommended" Why? By who?

I ask because they suck. Especially t-12 shoplights which really suck relative to high intensity discharge lights. Don't get me wrong, I have some and use them. And if all you need is a little more light then knock yourself out. But I also have an 400W HPS and its a thousand times better. Even the nicer compact bulbs, T-8's, t-5's, whatever, you're just putzing around relative to any HID lamp.

Only concern with seedlings would be too much light intensity and heat, which you can mitigate by increasing the distance between the bulb and leaves. Also, my neighbors think Im weird and wonder what Im growing upstairs.

We are all weird but our yards are nicer.

They're always used Tcharles by growers as well (in and out of 'prophouses') and you'll read literature just about everywhere that discusses the importance for their use in propagating both cuttings and seedlings.

Commonly as you read Dirr, he'll recommend the use of fluorescents for "starting woody plants." And that's from some of the best books written for propagation as you know from having discussed Maples, etc with me in the past.

And sure you can use any light, however the "low output" of a fluorescent is much more accomodating to a cutting.

Maybe I'm all wrong. I've been wrong before.

Dax

I see where you're coming from, fair enough, but the use of fluorescent lights by professionals in propagation, and Dirr's reccomendation that professionals use them almost defintely has much more to do with cost than best horticultural practice.

Fluorscents are cheap. Cheap to buy. Cheap to run. But they are not bright. And all plants benefit from brighter lights up to a point. A fluorescent may put out several thousand lumens when you touch the meter to the bulb, but only a few inches away intensity diminshes dramatically. And two feet away its almost useless, and in fact is entirely useless when plants are more than a few inches tall because only the surfaces at the top of plant are getting any light. Fluorescent isnt powerful enough to penetrate.

So you can place the lamp very close to baby plants or cuttings (at which point you block all natural light you have) but that's a poor substitute when the plants grow a little. The good thing about being a hobbyist is that sometimes you can use better practices than professionals because you don't need to make money.

Anyway, I don't want to start WWIII here. I am already engaged in a battle with the neighborhood cats and cant fight on two fronts.

Fluorescents are fine for some things, but they definitely have limitations. And if they are in fact "reccomended" it's not because its best for the plants, just might be a commercially feasible practice.

As for light intensity on cuttings. I disagree a little. Cuttings benefit from higher light intensity as well, provided very high humidity is maintained. See "Rooting Cuttings Under a Wet Tent" in the combined proceedings of the international plant propagators society. Vol 32. Page 450, which I will email to you momentarily.

Peace.

T

Truth. Good chat.

Later,

Dax

You lost me there, tcharles26 -- when you say HPS, does that mean High Pressure Sodium light, or what ?
Does it have a good spectrum, similar to the sun ?
Thanks for clarification, in advance.

PS. for others -- since the fluorescent lights are NOT hot to the touch, it shouldn't bother the plants, even if the tips of the foliage is touching.
Also, since the light is relatively less intense than the sun, even at short distance, it seems appropriate to compensate with longer exposure time.

You lost me there, tcharles26 -- when you say HPS, does that mean High Pressure Sodium light, or what ?
Does it have a good spectrum, similar to the sun ?

Yes. Mine is a high pressure sodium. As far as spectrum, its orangish yellow thats all I know. When I say HID I mean any high intensity discharge (sodium or metal halide)Metal halide looks more like the typical fluorescent, bluish color.

I dont know too much about spectrums, which is best, my impression is that's of marginal importance, at least relative to intensity, but that's just my impression.

For seedlings and stuff you dont need an expensive HID light. But they are cool. I have tomatoes growing under mine right now. I just finished a bunch of poinsettias under it.

Thanks.
I think there might be a problem though:
Spectrum is at least as important as intensity, because photosynthesis by plants requires certain light frequencies (colors).
If I recall correctly, the two important colors are blue and red -- which is why the leafy parts of plants appear green(ish): they absorb those two colors, but reflect or transmit those they don't use -- green and yellow.
Also as I recall, High Pressure Sodium lights emit in two narrow bands of color, both of which are yellow, thus of no use to plants.
The metal halide lights are probably better, but I don't recall the details anymore -- perhaps someone else does ?

"Spectrum is at least as important as intensity" I dont think that's accurate. Maybe someone else can verify. I do know that plants grow well under HPS lights. IVe seen them do it.

Metal halide is different, not necessarily better. I do know that metal halide are less efficient from the watt to lumen perspective and that the lose intensity faster (as the bulb wears out.)

And the bulbs for either aren't cheap. Mine is like 40 bucks to replace. There is a "growing under lights Forum" here on gardenweb. Thats where I learned about this stuff. One of the experts there would know much more than I.

t

I read to change out fluorescent lights the other day every three months. I change mine about every three years.

The sun is the best. A metal halide would be perfect (but again hot) and on a track system it could be a huge winner. Sodium bulbs are used to force a plant to flower and to promote more flowering. I agree though that any old bulb will grow a wimpy seedling, therefore I choose "the fluorescents"!

I think either way though, I'll end up burning my house down. My wiring is beautiful!

Dax

Unfortunately the link to the article I read no longer works.

According to Wikipedia, "Chlorophyll.... is a green photosynthetic pigment found in most plants, algae, and cyanobacteria. Its name is derived from ancient Greek: chloros = green and phyllon = leaf.
Chlorophyll absorbs most strongly in the blue and red but poorly in the green portions of the electromagnetic spectrum, hence the green color of chlorophyll-containing tissues like plant leaves.
......Because of chlorophylls selectivity regarding the wavelength of light it absorbs, areas of a leaf containing the molecule will appear green.
.....in vivo the total absorption spectrum is broadened and flattened such that a wider range of red, orange, yellow and blue light can be absorbed by plants and algae. Most photosynthetic organisms do not have pigments which absorb green light well, thus most remaining light under leaf canopies in forests or under water with abundant plankton is green, a spectral effect called the "green window".
[...]
Chlorophyll absorbs at 655nm and 411nm [ = nanometers of light wavelength].

Chlorophyll absorbtion spectrum shown on the Wikipedia, page:

{{gwi:869071}}

Wikipedia also has some interesting information on sodium lights :
"High pressure sodium (HPS) lamps..... contain some other elements (for example, mercury), produce a dark pink glow when first struck, and produce a pinkish orange light when warmed up. The sodium D-line is the main source of light from the HPS lamp, and it is extremely pressure broadened by the high sodium pressures in the lamp, hence colors of objects under them can be distinguished.
[....]
the blue and green lines are sodium lines which are otherwise quite weak in a low pressure discharge, but become intense in a high pressure discharge.
[....]
Sodium emits light on only one wavelength, and therefore is the easiest to filter out.

One consequence of widespread public lighting is that on cloudy nights, cities with enough public lighting are illuminated by light reflected off the clouds. As sodium vapor lights are often the source of urban illumination, this turns the sky a tinge of orange."

From the above, I would conclude that while most of the light from HPS lamps is of the wrong color, there may be a sufficient amount of blue & red to sustain plants.

HPS lamp spectrum shown on the Wikipedia, page:

{{gwi:869072}}

RE: "From the above, I would conclude that while most of the light from HPS lamps is of the wrong color, there may be a sufficient amount of blue & red to sustain plants."

That has to be true. I know Ive seen references to empiracal studies that say plants grow very well under sodium lamps. I'll post some pics of my tomatoes if you like, they are dwarf varities but are just going crazy.

This was a good topic. Good thread. Sorry if I sounded like a jerk.

T

Ref.: Johnstone & Brown (1976). Low-pressure sodium (SOX) tube lights as a source of supplementary lighting for the improved growth of Sitka Spruce seedlings. Forestry Commission Research and Development Paper 111.

Seedlings grown with supplementary light for 30 weeks achieved about twice the height of control seedlings with only natural daylight, and also better than seedlings with supplementary mercury vapour fluorescent lighting.

Resin

Interesting !
If its only "supplementary light," could the result be due to a heating effect ? (are sodium lights warmer than mercury lights ?)
What do you make of it Resin ?
Anyway, I'm not so sure keeping mercury vapour lamps in the house is such a good idea -- you break one of those things, and you get mercury contamination everywhere....

Hi Jaro,

It wouldn't be heating effect, as the SOX and controls were kept at the same temperature. The supplementary refers to on top of natural daylight.

I'd not worry too much about mercury vapour lamps, the amount of mercury in them is very small. Almost every school and office building in the world uses them (I remember a few getting broken by kids throwing things around when I was at school). Just clean up carefully after any do get broken (see details below; scroll down to #Mercury toxicity).

Resin

Well, if the experiment was carefully controlled, then someone should write to Wikipedia, that there's something wrong with the photochemistry of chlorophyll, that everyone's been assuming to be correct, 'till now :O)

I've seen sodium's in prophouses. I guess I assumed they were trying to force bedding plants to produce flowers and to provide supplemental light (in 'some' form).

I guess I always knew that indoors a stronger output lamp was always better than a weaker lamp and too that the type of wavelength had its' own effects as well, but when you just want to tool around in the basement, there's certainly nothing wrong with fluorescents and there's also people in high numbers using them as well.

Then there's timing where literally two types of 'timing' are involved. First, when the seeds germinated meaning how much more time is there until they'll be fine to grow outdoors, and a secondary timing, where the light cycle can be reduced with fluorescents, halides, and sodium's to force a plant to begin flowering. I used to grow petunia's etc - and I'd drop the light cycle to 10 hours on from 16 hours and within a few weeks the plants would begin to flower. Then after they start flowering, you can kick it up again to 14 or 16 hours and they'll continue flowering (at least with fluorescents).

That's all I know about this stuff and it's certainly been an interesting discussion. Don't know exactly how my thoughts mesh, but that's to be debated.

Dax

so some cheap full spectrum flourescents will do the thick?

Im not spending a bunch on HPS, or metal halide.

Interesting article:

April 11, 2007
Scientists predict nongreen plants on other planets
(SNIP)

Scientists have long known that the chlorophyll in most plants on Earth absorbs blue and red light and less green light. Therefore, chlorophyll appears green. Although some green color is absorbed, it is less than the other colors. Previously, scientists thought plants are not efficient as they could be, because they do not use more green light.

According to scientists, the Sun has a specific distribution of colors of light, emitting more of some colors than others. Gases in Earth's air also filter sunlight, absorbing different colors. As a result, more red light particles reach Earth's surface than blue or green light particles, so plants use red light for photosynthesis. There is plenty of light for land plants, so they do not need to use extra green light.
(SNIP)

Regarding mercury in lights:

The CFL mercury nightmare
Steven Milloy, Financial Post, April 28, 2007

How much money does it take to screw in a compact fluorescent light bulb? About US$4.28 for the bulb and labour -- unless you break the bulb. Then you, like Brandy Bridges of Ellsworth, Maine, could be looking at a cost of about US$2,004.28, which doesn't include the costs of frayed nerves and risks to health.

Sound crazy? Perhaps no more than the stampede to ban the incandescent light bulb in favour of compact fluorescent light bulbs (CFLs).

According to an April 12 article in The Ellsworth American, Bridges had the misfortune of breaking a CFL during installation in her daughter's bedroom: It dropped and shattered on the carpeted floor.

Aware that CFLs contain potentially hazardous substances, Bridges called her local Home Depot for advice. The store told her that the CFL contained mercury and that she should call the Poison Control hotline, which in turn directed her to the Maine Department of Environmental Protection.

The DEP sent a specialist to Bridges' house to test for mercury contamination. The specialist found mercury levels in the bedroom in excess of six times the state's "safe" level for mercury contamination of 300 billionths of a gram per cubic meter. The DEP specialist recommended that Bridges call an environmental cleanup firm, which reportedly gave her a "low-ball" estimate of US$2,000 to clean up the room. The room then was sealed off with plastic and Bridges began "gathering finances" to pay for the US$2,000 cleaning. Reportedly, her insurance company wouldn't cover the cleanup costs because mercury is a pollutant.

Given that the replacement of incandescent bulbs with CFLs in the average U.S. household is touted as saving as much as US$180 annually in energy costs -- and assuming that Bridges doesn't break any more CFLs -- it will take her more than 11 years to recoup the cleanup costs in the form of energy savings.

The potentially hazardous CFL is being pushed by companies such as Wal-Mart, which wants to sell 100 million CFLs at five times the cost of incandescent bulbs during 2007, and, surprisingly, environmentalists.

It's quite odd that environmentalists have embraced the CFL, which cannot now and will not in the foreseeable future be made without mercury. Given that there are about five billion light bulb sockets in North American households, we're looking at the possibility of creating billions of hazardous waste sites such as the Bridges' bedroom.

Usually, environmentalists want hazardous materials out of, not in, our homes. These are the same people who go berserk at the thought of mercury being emitted from power plants and the presence of mercury in seafood. Environmentalists have whipped up so much fear of mercury among the public that many local governments have even launched mercury thermometer exchange programs.

As the activist group Environmental Defense urges us to buy CFLs, it defines mercury on a separate part of its Web site as a "highly toxic heavy metal that can cause brain damage and learning disabilities in fetuses and children" and as "one of the most poisonous forms of pollution."

Greenpeace also recommends CFLs while simultaneously bemoaning contamination caused by a mercury-thermometer factory in India. But where are mercury-containing CFLs made? Not in the United States, under strict environmental regulation. CFLs are made in India and China, where environmental standards are virtually non-existent.

And let's not forget about the regulatory nightmare in the U.S. known as the Superfund law, the EPA regulatory program best known for requiring expensive but often needless cleanup of toxic waste sites, along with endless litigation over such cleanups.

We'll eventually be disposing billions and billions of CFL mercury bombs. Much of the mercury from discarded and/or broken CFLs is bound to make its way into the environment and give rise to Superfund liability, which in the past has needlessly disrupted many lives, cost tens of billions of dollars and sent many businesses into bankruptcy.

As each CFL contains five milligrams of mercury, at the Maine "safety" standard of 300 nanograms per cubic meter, it would take 16,667 cubic meters of soil to "safely" contain all the mercury in a single CFL. While CFL vendors and environmentalists tout the energy cost savings of CFLs, they conveniently omit the personal and societal costs of CFL disposal.

Not only are CFLs much more expensive than incandescent bulbs and emit light that many regard as inferior to incandescent bulbs, they pose a nightmare if they break and require special disposal procedures. Yet governments (egged on by environmentalists and the Wal-Marts of the world) are imposing on us such higher costs, denial of lighting choice, disposal hassles and breakage risks in the name of saving a few dollars every year on the electric bill?

- Steven Milloy publishes JunkScience.com and CSRWatch.com. He is a junk-science expert and advocate of free enterprise, and an adjunct scholar at the Competitive Enterprise Institute.