Light bulbs

Anita Roselle
Sun, 05 Mar 2017 15:11:15 PST
Leo, me again,

I am sorry that I sort of got it confused. What I need is a bulb that will
fit in my window that is less than 4'. It seems that the next size down is
2'.  I want one of those narrow bulbs that is high out-put and energy
efficient. If I look on line, is it a T5HO, 6,500 K color temperature that
will give a lot of light in a small space and be highly efficient? I want a
fixture with a reflector but rather narrow like in a fish tank set up,
there are a number of hydroponic places here and pet [fish] stores as
well.  I can construct a wood frame to hold it up and have a long enough
cord that I can plug it ion a timer.

Where is Old Bridge, NJ, I am not familiar with it?  I used to live in the
Delaware Valley area of PA.

I really appreciate you helping with this, I would spend hours trying to
find what it is that I want.

Anita R.

On Sun, Mar 5, 2017 at 5:47 PM, Anita Roselle <>

> Martin, I agree if I was growing tomatoes or seedlings that I wanted to
> stay compact I would use them, just where they are not in front of my eyes
> at the kitchen sink or in the living room. That is interesting that they
> stimulate buds on freesias. I did not mean to say they were not effective.
> I am new to this forum, I'a a long time plant person just now getting
> interested in more bulbs. I have a greenhouse so most things are out there
> and only a few in the house.
> On Sun, Mar 5, 2017 at 3:39 PM, Garak <> wrote:
>> Hi,
>> I can confirm the the 3 wavelength LED (Red, orange, blue) are quite
>> effective for plant growth, e.g. tomatoes stay compact and freesias grow
>> buds  - I've yet to find a plant that is not compatible. I agree that those
>> are too irritating for a living room or for enjoying flowers, but they do
>> work well for seedlings in my study room next to the computer, and for
>> those plants that need light over winter in a small side chamber. for me,
>> they are the winner for price-performance ratio plus they seem realtively
>> safe since they are "cold".
>> Martin
>> Am 05.03.2017 um 21:21 schrieb Anita Roselle:
>>> Leo, I want to thank you for all the information on electric lighting.
>>> I used lights years ago when the best was 2 different fluorescent bulbs
>>> in
>>> a 2 bulb fixture. I now wish to put some light on my african violets that
>>> do not get enough light in the winter to bloom. I have been befuddled
>>> about
>>> what to buy as there are so many choices, perhaps all of which I know
>>> nothing about. You have spelled out for us what the different options are
>>> and what they do. I now know what I need to look for and be confident
>>> that
>>> I am getting the best light at the best cost. I will look for a 2'
>>> compact
>>> fluorescent fixture with a single high-output T5 bulb. This is at the
>>> window over my kitchen sink and I don't like the weird light I have now.
>>> I did purchase from Amazon a clip on light, I wanted the clip, that has a
>>> whole lot of small bulbs of different colors, I think red and blue, are
>>> they LED's? They get the plants to bloom but the color is such that the
>>> blooms to peoples eyes are not true to their real color, in fact they
>>> look
>>> weird.
>>> Thank again,
>>> Anita R.
>>> On Sun, Mar 5, 2017 at 1:45 PM, Leo Martin <> wrote:
>>> Norton asked about supplemental lighting for sprouting bulb seedlings
>>>> indoors.
>>>> Technology is changing rapidly. In 5-10 years light growers will
>>>> probably
>>>> be using LED lights, with only a few holdouts. LED lights are more
>>>> expensive to buy today, but less expensive over their lifespan when
>>>> considering the lower electricity usage. I have read analyses suggesting
>>>> the break-even point is 6 months to 2 years.
>>>> Light gardeners have abandoned incandescent bulbs. They are inexpensive,
>>>> but most of the electricity is wasted producing heat. The bulbs do not
>>>> last
>>>> long.
>>>> High-pressure sodium lighting (HPS) is very expensive to buy, uses a
>>>> lot of
>>>> electricity, and produces the most heat of any lighting used for
>>>> horticulture. The lamps are so hot a person would get a third-degree
>>>> burn
>>>> from a single touch lasting less than a second. Water on an illuminated
>>>> lamp - like from a spray bottle - causes an explosion, showering
>>>> near-molten glass all over the growing area. I would not recommend HPS
>>>> to
>>>> any home grower, under any circumstances, because of the heat danger.
>>>> Much
>>>> safer and equally effective alternatives exist. This kind of lamp was
>>>> used
>>>> for commercial indoor herb growing for years, but these growers have
>>>> switched to other lighting.
>>>> Different kinds of fluorescent lighting work well for growing plants,
>>>> and
>>>> have been standards for some years. Fluorescent grow lights will be
>>>> replaced by LEDs over the next few years for reasons of efficiency and
>>>> lifetime cost. Another problem with fluorescent lights is that they
>>>> contain
>>>> mercury, and LEDs contain little or none.
>>>> Hobbyists used standard fluorescent tubes for years; compact fluorescent
>>>> lights (CFL) also work well, and use less electricity. Most indoor
>>>> fluorescent light growers choose long tubes because the fixtures fit
>>>> better
>>>> under shelves or over windowsills. Spiral fluorescent lights also work
>>>> well. When a spiral lamp is used, the long axis of the spiral should
>>>> point
>>>> down at the plants, since spiral lamps are designed to emit more light
>>>> along the axis rather than from the sides. All fluorescent lamps need
>>>> to be
>>>> replaced at least every 12 months. Their light output begins decreasing
>>>> within 6 months, and most are down to 75% or less of the initial output
>>>> by
>>>> a year. The human eye does not see this, but the plants do. If you
>>>> choose
>>>> to use fluorescent lamps, write the date placed into service on the tube
>>>> with an indelible marker, and replace every 9-12 months. Standard
>>>> fluorescent lights are hot, but not as hot as an incandescent bulb. They
>>>> will cause a burn but most people would remove their hand from the hot
>>>> tube
>>>> before serious injury.
>>>> Long fluorescent tubes are labeled as to the size of the tube. Standard
>>>> tubes are T8. They can work well for growing plants if wattage and color
>>>> are chosen correctly. Higher-wattage tubes produce more light, and most
>>>> people choose 40 Watt T8 tubes rather than 20 W. A very common fixture
>>>> for
>>>> light growers is sold as a shop light; it holds two, 4 foot / 122cm
>>>> long T8
>>>> tubes. They are easy to suspend underneath shelves. Several can be
>>>> plugged
>>>> into a power strip, which can be plugged into a heavy-duty electric
>>>> timer.
>>>> Aquarium, terrarium and some plant growers often use high-output T5
>>>> tubes
>>>> (T5HO), which produce more light for the electricity used than standard
>>>> tubes. T5s are smaller in diameter than T8s and require different
>>>> fixtures.
>>>> High-output lamps require different fixtures than standard output. Many
>>>> indoor growers buy T5HO aquarium light fixtures for their plant stands.
>>>> The
>>>> fixtures and tubes are more expensive than standard T8 fixtures and
>>>> tubes,
>>>> but when considering the cost of electricity over the life of the
>>>> fixture
>>>> they cost less to run than T8s. They are readily available at aquarium
>>>> shops and online. T5HO fixtures come in different lengths, for different
>>>> sizes of aquarium, so it may be easier to find a T5HO fixture to fit a
>>>> small space as compared to T8 fixtures. T5HO tubes are hotter than
>>>> standard
>>>> T8 tubes.
>>>> Fluorescent lights are available in different light colors, which is
>>>> measured in degrees Kelvin (K.) This is a measure of how the light
>>>> appears
>>>> to the human eye, and has nothing to do with the actual Kelvin
>>>> temperature
>>>> scale. It also says nothing about the actual frequencies of photons
>>>> making
>>>> up the light. It turns out that fluorescent lights with a light color of
>>>> 6,500 K are good for growing plants, so this is what most people buy.
>>>> Some
>>>> manufacturers refer to 6,500 K color temperature as "daylight", but
>>>> others
>>>> use "daylight" to refer to other color temperatures. Look for the
>>>> number on
>>>> the box or label. Other light colors alone are not as good for growing
>>>> plants as are 6,500 K. Generally, there is no advantage to adding lamps
>>>> with other light colors to lamps of 6,500 K. Aquarists can buy 10,000 K
>>>> high-output T5s, which provide brilliant white light. But, plants don't
>>>> grow very well under this; it is designed for corals. Many T5HO fixtures
>>>> are sold with 10,000 K and actinic blue tubes, neither of which works
>>>> well
>>>> for plants, so it is better to buy a fixture and tubes separately.
>>>> LED lights of color temperature 6,500 K are not necessarily the best for
>>>> growing plants, The usefulness of 6,500 K color temperature applies
>>>> only to
>>>> fluorescent lights.
>>>> Compact fluorescent lamps use less electricity for the light output
>>>> compared to standard fluorescents, so many light growers are switching.
>>>> 4
>>>> foot long CFL tubes fit into some standard 4-foot, 2-tube fixtures, but
>>>> not
>>>> all. Some CFL tubes are made to fit into older fixtures, and other need
>>>> fixtures specifically for CFL tubes. Most spiral CFL lamps fit into
>>>> older
>>>> standard socket fixtures. The least-expensive solution if CFL is chosen
>>>> would be standard 4 foot long shop fixtures, each holding two CFL tubes.
>>>> Choose 6,500 K color temperature, and the highest Wattage available.
>>>> Until
>>>> recently indoor commercial growers used CFL lamps of 6,500 K color
>>>> temperature at the highest Wattage they could get.
>>>> LED (Light-Emitting Diode) lighting is still being developed and
>>>> perfected.
>>>> Until recently attention was placed on light for human use, and not
>>>> much on
>>>> plant growth. So, most knowledge of how LED lighting works for plants
>>>> has
>>>> been trial-and-error. LEDs last perhaps 3-5 years when used 12 hours per
>>>> day. They are more expensive to buy, but use much less electricity than
>>>> other lamps. Over their life they are less expensive to run.
>>>> Individual LEDs emit only certain wavelengths of light, and multiple
>>>> wavelength LEDs are combined to give the desired light color as seen by
>>>> the
>>>> eye. Individual LEDs are rectangles about 2 millimeters square. Multiple
>>>> LEDs are wired into strips or rectangular arrays, and a protective
>>>> covering
>>>> usually put over them, to form lamps. LED lamps are available as
>>>> flexible
>>>> linear strips, lamps resembling fluorescent tubes, and lamps resembling
>>>> incandescent bulbs. The tube-like LED lamps require their own fixtures
>>>> and
>>>> generally cannot be used in older fluorescent fixtures. The
>>>> standard-socket
>>>> LED light bulbs can be fit into older sockets.
>>>> At first growers tried to match LED wavelength emitted to the known
>>>> maximum
>>>> absorption peaks of chlorophyll, which produced ghastly-looking pink and
>>>> blue light. It has since been realized chlorophyll absorbs and uses
>>>> other
>>>> wavelengths quite well, so these pink and blue LEDs are now considered
>>>> unnecessary. The idea of a "good" LED lamp for plants includes whether
>>>> proper wavelength photos are emitted. You will read of`a measurement
>>>> called
>>>> PAR, photosynthetically active radiation. This measures what proportion
>>>> of
>>>> the photons emitted by the LEDs are used by the plants. Recall color
>>>> temperature measures how the light looks to the human eye. Different
>>>> combinations of light wavelength can yield what we think is white light.
>>>> LED color temperature has not been found useful for deciding which lamp
>>>> to
>>>> use on plants, so don't go looking for 6,500 K LED lamps. People are
>>>> also
>>>> concerned with how many photons are emitted for the electricity input
>>>> (efficiency.)
>>>> Not many smaller LED lamps have been designed specifically for plants,
>>>> so
>>>> it can be difficult to choose. However, by trial and error, people have
>>>> reported some lamps work well. In general, most bright white lamps
>>>> produce
>>>> acceptable growth. An LED shop light Home Depot sells has been found to
>>>> work well:
>>>> White-LED-Chain-Mount-
>>>> Shoplight-1290L/204378710
>>>> as have various LED light bulbs designed to be screwed into desk lamp
>>>> sockets.
>>>> Commercial indoor growers are switching to LED arrays:
>>>> luminaire-48/
>>>> and plasma lighting
>>>> plasma-02-ac-lep/
>>>> but these are for very valuable crops.
>>>> So, for Norton... Can you buy in Peru standard T8 fluorescent light
>>>> tubes
>>>> and fixtures with 6,500 K color temperature ("daylight"), 20 or 40 Watt?
>>>> (40W is better.) We know those work well, and will not require
>>>> importing.
>>>> This would be your simplest solution. Tubes must be changed once per
>>>> year.
>>>> Or, can you buy in Peru T5HO intended for aquariums, with color
>>>> temperature
>>>> 6,500 K? Those work well and are more efficient than standard T8. The
>>>> tubes
>>>> must be changed once a year.
>>>> It is hard to carry long, fragile objects on airplanes. Imported CFL
>>>> tubes
>>>> only last a year. Imported LED lights will last 3-5 years.
>>>> People could bring you this light from the US, since it is know to work
>>>> for
>>>> plants. It is not as fragile as are fluorescent tubes:
>>>> White-LED-Chain-Mount-
>>>> Shoplight-1290L/204378710
>>>> They could also bring you a T5HO aquarium fixture from the US, perhaps
>>>> with
>>>> some replacement 6,500 K bulbs. Again, these are long and fragile.
>>>> Of course, there is no way to tell what will be available in 3-5 years.
>>>> Leo Martin
>>>> Zone 9?
>>>> Phoenix Arizona USA
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>> --
>> Martin
>> ----------------------------------------------
>> Southern Germany
>> Likely zone 7a
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