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Incandescent and Fluorescent Bulbs in Hydroponics · Hydroponics Daily

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Hello and welcome back to Hydroponics Daily. Today is the first episode about
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lighting and I'm going to do a few episodes about lighting, all the different
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types of lighting including the sun,
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and today we're going to start off with incandescent light bulbs and fluorescent
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bulbs because I'm lumping them together because they really can't do a full
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episode on incandescent light bulbs because there's just not enough to talk about.
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So incandescent light bulbs are the traditional light bulbs you remember with
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the filament and they have slowly been replaced by LED lights and fluorescent
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lights in the home, so in lamps and things like that.
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But they are still used in horticulture and a lot of nurseries that grow photoperiodic
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plants actually stockpiled incandescent light bulbs when they were banned in
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Europe and in the UK because they were so useful.
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Now they're not using them as grow lights, they aren't using them to drive photosynthesis.
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These are on nurseries where you want to manipulate the photoperiod,
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so extend the period of light that the plants actually perceived light for.
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Now many hydroponic growers, indoor growers, will
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just think well i just put my lights on for 12 hours or
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18 hours or 20 hours and that's how
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i extend the photo period but if you're growing something like
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a poinsettia or a chrysanthemum and you
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don't you're actually using sunlight in a greenhouse for
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photosynthesis and it would be too expensive because of
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the crops and the economics to actually extend them the actual
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photo periodic time to 20 hours
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you don't actually want the plant to be photosynthesizing for
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20 hours it's not economical you just want the plant to
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perceive the light and plants can perceive
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day length at much lower light levels than they
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can actually photosynthesize at so there
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have been problems before where where like street lamps that have been put up
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next to greenhouses and they've screwed up the photo period of the plants growing
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in the in the greenhouse that plants can detect such low light levels as a photo
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period and so what growers do is actually rather than putting loads of grow
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lights in their nursery.
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They actually just put one or two incandescent light bulbs in and obviously.
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Using a very very small amount of light and they actually massively
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increase the the photo period that plants are perceiving so
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they can the light you know the sun might go down at four o'clock
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in the winter but you could just have a few incandescent light bulbs on and
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the plants will perceive it till 11 o'clock at night incandescent labels are
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really good for this they're not the most energy efficient but because of the
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spectrum they produce plants perceive it really well so They produce a lot of
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red light at 660 nanometers,
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and that is where plants detect day length.
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The pigment that they use is phytochrome. It's not chlorophyll,
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chlorophyll photosynthesis, phytochrome for day length and other sort of light quality issues.
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So incandescent light bulbs are used for that. I'm not aware of anyone who's
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used incandescent light bulbs to drive photosynthesis as grow lights.
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Maybe back in the day, in the 50s and 60s, they did. but that's
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certainly not the case fluorescent lights so the
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tubes and the and the
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bulbs so the tubes have been used
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routinely in grow rooms in the past so
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when i was phd student and a
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postdoc so in the early 2000s fluorescent
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light bulbs in grow cabinets and grow
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rooms at universities were were the standard
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and so we would have phytotrons these big
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cabinets you'd go in and all the air conditioning you know
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the units you can precisely control light levels
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and photoperiod but they would still be using fluorescent tubes
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because that was what we had we didn't have
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led lights at that period sodium lamps would have been producing too much heat
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and the spectrum would have been not quite right so fluorescent lights were
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really good for that and they were really good in micropropagation labs as well
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and still are used in micropropagation labs because you can produce a lot of
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light with very efficiently.
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And it gets the plants photosynthesizing a
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bit it's not the optimum for photosynthesis but they
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they're very cool so they're really good in grow rooms
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where you want micropropagation or to study plants they're also
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still used fairly routinely in propagation
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so if you have a propagation tank you can use you
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can get an array so a linked up series of t8s
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i think it is or t5s the the fluorescent tubes
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and they work really well still you obviously
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you need to direct the light back down to the plants because
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it's being produced 360 degrees so they'll
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often have a reflector at the top and that's one of
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the issues is that when you get into actually really want
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to supercharge photosynthesis fluorescence start to
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be not the best option so you
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wouldn't put fluorescence in a in a greenhouse or a grow room
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because they're shooting off light in 360 degrees
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anyway and there's a lot of coverage
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required to get a decent light intensity so
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if you're in a greenhouse you would during the
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day you'd be stopping all that sunlight from getting
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to the plants because the whole canopy would just
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be covered in fluorescent lamps and the same in a grow room you your
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entire roof would be fluorescent lamps and
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you still wouldn't be producing as much light as you could with sodium lights
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or with leds so that's why you
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don't see fluorescent lights used for growing it's only for propagation
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and in old style grow rooms.
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So fluorescent lights that they're cheap and cheerful that
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so you might think well why don't you just use leds in
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your micropropagation unit or your in your grow tent your
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your your for your cuttings your propagation tent and
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you can and there are a lot of replacement bulbs now
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where you can get leds that are like for like
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replacements with the fluorescent tubes they won't fit the same electrical connectors
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because you need a special ballast for a fluorescent a little i don't know what
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the word is an inverter is it i'm not an electrical expert but the basically
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they won't retro you can't retro install.
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Led lights into fluorescent tubes you have to rework it
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so you're better off just buying a whole new i don't
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know what the word is holder for your led lights and fixing them
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to your your propagation tent led lights
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will be a lot better for propagation because they again
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they'll be very efficient but you actually can fine tune the the.
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Spectrum for what you need and for propagation you
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probably want a bit of far red light in there not many times you'll
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hear me saying that far red light is good for growing crops but
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if you if you want to stimulate rooting a bit of far red would be good and
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the other good use for fluorescence i forgot about this one is
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that fluorescence are a really good way of producing a black light
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a uv light and i still
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use this with i get i've got a uvb light that
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is designed for growers growers people
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who keep reptiles so that for
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reptiles for some reason need uv light and
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so you can get a uvb light and it's a fluorescent light
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a compact one so one that goes in a normal bulb socket
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you know like a an incandescent bulb socket and
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that produces a good level of uv uv light they're
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made of a they have a special phosphor which
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is the the chemical that emits light in in fluorescent
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lights and mercury phosphor and then they
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have a special glass that goes around it because normally glass prevents
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the emission of uv light it stops uv that's why you don't get sunburns in a
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greenhouse but you can in a polytunnel that's why you don't get sunburns in
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your house because the uv light's not coming through so you need a special type
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of of of glass and i'm trying to find what it's called.
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What's it called here we go let's have
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a look yeah it's woods glass which
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sounds like it's made of wood but it's not it's an optical glass invented
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in 1903 that is a long time ago
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considering lighting technology and it passes allows
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ultraviolet and infrared light to pass through while
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blocking most visible lights so a black
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light can have a a peak one single peak
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at 380 nanometers whereas normally
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a a fluorescent light
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has a number of different peaks and it's particularly
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high in green light and
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that's why it's good for human perception because
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humans have evolved to perceive green light really
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well and so that's why
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when you see a really like industrial fluorescent light it looks really bright
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and almost oppressive not kind to the eyes and people like sunlight and that's
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why bulb manufacturers are always trying to get sunlight close to sunlight there's
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a guy in my village and he's his house is illuminated with industrial,
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fluorescent light bulbs and i was thinking i would hate to live there because
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his house must be horrible to live with so.
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Big strong emission in green and then peaks at
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certain others so it doesn't it doesn't reflect sunlight very
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well and so that's why fluorescence another
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reason why fluorescence is not used very often green light
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can be used by plants things like carotenoids anthocyanins
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they can use it for photosynthesis however it's not
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the best form of light it's not energy efficient
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for the photons to be absorbed into photosynthesis that's
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why plants are green because they're emitting green light
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they're just you know not the ones that are
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in the canopy the primary plants are
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just not using green and so they they emit it out
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that's why and so they transmit it or reflect it
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they're absorbing the red and blue that's why they look green
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now under canopy plants will use green because that's all that's left you think
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about in the rainforest the canopy trees the orchids the bromeliads way up there
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they've absorbed all all the red and the blues and the oranges and they're just
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the plants on the bottom floor will be able to, that's all they've got is the green light.
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And so things like Calanthia, which is from the Amazon rainforest,
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they often have really purple leaves because they are reflecting purple when
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they're brought out of the understory.
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And so they're able to use the green.
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So you might have a shade loving plant, but for most plants,
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you don't want fluorescent bulbs that are high in green.
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So that's why we don't see fluorescent bulbs on sale very often.
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And the other thing that you have to consider with fluorescent bulbs
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is they contain a significant amount of mercury
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and so if your bulb smashes above your plants and
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you don't pick up all the bits then you could potentially get mercury contamination
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of your growing media and your plants so that's not good especially that
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dust when that dust flies when a fluorescent bulb smashes
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that's that dust is going over your crops you don't want to
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be inhaling or smoking or eating mercury dust
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other thing to consider with fluorescent bulbs is that
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they do emit a small amount of uv light about this
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so if you sat under a uv light which i'm doing at the moment
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sorry a fluorescent light i'm sat under a fluorescent bulb here and if i'm sat
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here for eight hours in this office i will get the same amount of ultraviolet
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light absorption into my skin as if i were sat outside for one minute which
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is not very much but if you're really if you're if,
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you were albino that might be an issue and if your plants were sensitive to
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uv light then that might be an issue most plants a small amount of uv light
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is actually beneficial there are a number of companies actually selling uv.
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Emitting leds now to prime plants
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for beneficial effects like
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improved stress tolerance abiotic stress
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so environmental stress and stress resistance disease
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transplant shock and also
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all sorts of crazy things so fluorescent lights
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could be a bit beneficial because they emit a small amount
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of uv if i was growing a crop and i wanted to
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stimulate pigment production i would stick a
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uv one of my little uv fluorescent plants in
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my grow room and put it on for a few minutes every day just
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to stimulate stress responses beneficial stress responses
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and pigmentation because if you
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put uv in the plants they'll often pigment up the red you'll
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get reds and and often purple purple
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tinges to your plants so that's a good tip you don't need
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to use fancy led uv lights for that but
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you can do and the advantage of them is that if
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you if they're integrated into the led arrays then.
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You get much more uniformity in your response whereas if you had just
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one uv light one bulb in the center you
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might get loads of pigmentation in the center and not
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at the edges so you know uniformity is very important
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for crops when you're growing them and trying to sell them import especially so
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that's been fluorescent bulbs for today i don't think
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i've covered pretty much everything i think i'm not going
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to go into the technical details of how fluorescent bulb works because a
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it's not important for hydroponics and b i
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don't know and i'm just going to be reading off websites if
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i did that and that would be dull as dishwater i suppose it's
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important to note that fluorescent bulbs are more they
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have a much longer lifespan than incandescent bulbs
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so they'll last longer need replacing less often but
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they will but they will burn out and the ballasts will
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burn out as well so they'll need replacing as well whereas leds
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and i think even sodiums will last longer than a fluorescent so that's been
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hydroponics daily for today incandescent bulbs their use in photoperiod oh before
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i go i have thought of another use for fluorescent bulbs and incandescent bulbs
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when you go into a greenhouse they're the.
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And view your plants now so often there'll
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be you'll get fluorescent light along the gullies where the
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aluminium gullies are in a greenhouse and obviously because
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fluorescence and incandescence are really attuned to the
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human eye they're really good for just illuminating the
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crops so you can walk in and do things when the when the
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grow lights aren't there or it's at night or early in the morning or late
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at night so you know don't think
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you don't have to install fluorescent lights if you're
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in a in a greenhouse or in a grow room because you might
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have to especially if you're using colored leds where it's that purplish or
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you've got multiple spectra and they're not and they're not white leds they
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don't you don't perceive them you could get very ill if you don't have fluorescent
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or incandescent light bulbs probably fluorescence you can get nausea,
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and obviously you can get eye damage as well because if you've not got that
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green light you can't perceive how intense the light is and your retinas can get burnt.
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So fluorescent bulbs are really good in greenhouses just for illuminating the
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crop, spotting pests and diseases.
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If you had purple LEDs and you're looking for pests, good luck trying to find
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a spider mite if you've got purple LEDs. You need a fluorescent bulb or a white
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LED to actually find them.
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So still use routinely for that use. That's been hydroponics data for today.
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Incandescent bulbs for used for photoperiod control
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in greenhouses fluorescent bulbs used for
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propagation and also what
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was the useful uv lights as well dark lights there were
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fluorescents are used okay if you found this interesting please share it with
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Thank you very much for listening. Until tomorrow, goodbye.