Good light source?

[Yorkshire Kris]

So comparing different daylight bulbs which have the full spectrum of light; the one with the higher lumens level is better?

Generally speaking it is safe to assume so and you'd be very unlikely to get the PAR ratings for anything that's not horticultural anyway.

By the way, 6400K emulates summer time sun light, is that really what you want at this time of year? I'm not sure. 2700K would be much closer to the actual sunlight that plants receive right now.

Well where the plants are in the house the temp is 15-22 degrees at the moment so yes as much light as possible.

I also dont think one bulb will create enough light to promote too much growth.

Perhaps also in the greenhouse.

[Vagetarian]

Yes, I'm getting concerned about the light levels in my conservatory as it has 4 solid walls and only the roof is glazed. It is warm because I eat dinner in there, I will see how it goes and maybe get one of the proper E40 CFL lamps (125-250W) to hang off the rafters during the day.

I don't think that anything less than 5 of those 30W CFLs will promote much growth at all. I started some tomatoes and peppers under about 200W of PLL fluorescent tubes this year and they still grew faster in the natural March daylight in the conservatory.

[Kristen]

Yes, probably a good idea. In my case I'm happy them make some growth, rather than just tick-over - they are all quite small plants, hence why they are in the conservatory for the Winter rather than being planted out.

[Vagetarian]

I'll be very happy if mine just 'tick over' to be honest. I love the conservatory filled up with jungley plants, when arranged nicely they almost don't look like I've rammed them all in there.

Mine are mostly large plants because I want them to be massive plants next year. I have a Maurelli in there that I got from B&Q this year which is pushing out leaves over 3ft long now I think I'm crazy

[Yorkshire Kris]

I'll be very happy if mine just 'tick over' to be honest. I love the conservatory filled up with jungley plants, when arranged nicely they almost don't look like I've rammed them all in there.

Mine are mostly large plants because I want them to be massive plants next year. I have a Ensete v Maurelii in there that I got from B&Q this year which is pushing out leaves over 3ft long now I think I'm crazy

My Montys are inside with 8 foot leaves, HELP!

[Kristen]

By the way, 6400K emulates summer time sun light, is that really what you want at this time of year? I'm not sure. 2700K would be much closer to the actual sunlight that plants receive right now.

Don't we want to emulate Tropic Light, rather than our more pathetic end-of-season light?

[Yorkshire Kris]

I used these Ebay Item: 270822704996

Item out of stock but gone for screw fixing instead. Packaging per bulb is annoying But that seems to be the case for all bulbs.

[Dave Brown]

Couple of points

All 2700K bulbs are banned here, it's that horrid warm white (yellow) colour which tries to mimic an incandescent bulb. Even the table lamps now are being converted to 6400K.

The 30w 6400K promotes good growth on shade loving plants and as I said in my previous post, Begonia 'Luxurians' grew very well under an 11w desk lamp last winter. By all means go for a 250w if you must boost energy companies profits, but for me it is not necessary. I leave starting off Tomatoes, peppers etc until March.

[Vagetarian]

My Montys are inside with 8 foot leaves, HELP!

Don't we want to emulate Tropic Light, rather than our more pathetic end-of-season light?

That is a very good point!

Which brings me to the question, what is the light like in the tropics?

Dave, all fluorescent lamps are banned in my house (except the shed). I am converting to LED. 6000 something K lamps in the bathroom/toilet and 2900K lamps everywhere else. My eyes prefer the light they create over fluoro and they're even more efficient!

I'm surprised that you grew some plants under an 11W light, but what about a whole room full of them?

[Dave Brown]

Dave, all fluorescent lamps are banned in my house (except the shed). I am converting to LED. 6000 something K lamps in the bathroom/toilet and 2900K lamps everywhere else. My eyes prefer the light they create over fluoro and they're even more efficient!

Sorry couldn't tolerate warm white, as is a very artificial light colour. Looked into LEDs but just too expensive, particularly for grow lights, easily 10 times the price of fluorescent, if not more. Would need a 10 year cost recovery time to break even with fluor's

I'm surprised that you grew some plants under an 11W light, but what about a whole room full of them?

Wife won't let me have a whole room of plants. Alocasia, Colocasia and many shade plants will grow happily in about 2000 lux. Just measured using the lux meter and the 11w daylight (6400k) bulb is 2000 lux at around 40cm

[Vagetarian]

Sorry couldn't tolerate warm white, as is a very artificial light colour. Looked into LEDs but just too expensive, particularly for grow lights, easily 10 times the price of fluorescent, if not more. Would need a 10 year cost recovery time to break even with fluor's

They are definitely more expensive but more in the region of 2x the price per watt, with LED being more efficient per watt anyway. A 220W fluorescent is £90 and a 200W LED is £200. In regards to domestic lamps, CFLs are government subsidised, they were actually quite expensive before that. LEDs are coming down in price massively. The first proper GU10 LEDs that I fitted which weren't accent lighting were £30 a piece! The dimmable ones I bought for my living room recently were just a fiver. I will save that off the electric bill in the first year.

I couldn't tolerate cool white in the living areas for the opposite reason, it seems unnaturally cold. The colour temperature of daylight actually ranges from sunrise to sunset. I think photographers use 5000K which represents daylight best of all. This puts 6700K almost as far away from true daylight as 2900K. 6700K fluoro lamps are called 'daylight' for marketing reasons. They do not emulate daylight, daylight is a full spectrum of colour and fluoro is not.

It seems to come down to what people are used to, since my light fittings were all halogens before, cool white was waaaaay too cool for my eyes. If I'd been used to fluoros I almost certainly would have gone for the cool white.

Wife won't let me have a whole room of plants. Alocasia, Colocasia and many shade plants will grow happily in about 2000 lux. Just measured using the lux meter and the 11w daylight (6400k) bulb is 2000 lux at around 40cm

Luckily, I've escaped marriage thus far.

That sounds fine if you can have the light 40cm away from all your plants. Mine are spread 3m. When you take the inverse square law into consideration, the lux at 3m would be almost non existent.

EDIT: http://www.telegraph.co.uk/news/worldne ... uture.html

EDIT2: What I really need to know is whether you guys think I actually need supplemental lighting in my conservatory. It is a very bright room with 4 white walls and a 3.5mx3.5m glazed roof. My main concerns are the Colocasia, Maurelli, Super Dwarf Cavendish and a couple other tender Musas. Along with various Musa seedlings up to 8" tall and any possible Musa seed that might germinate. I guess the seedlings will have to go in the cupboard I used for the tomatoes this spring.

[Kristen]

The colour temperature of daylight actually ranges from sunrise to sunset. I think photographers use 5000K which represents daylight best of all. This puts 6700K almost as far away from true daylight as 2900K. 6700K fluoro lamps are called 'daylight' for marketing reasons. They do not emulate daylight, daylight is a full spectrum of colour and fluoro is not.

We are after what the plants need for photosynthesis - so Blue for vegetative growth, and Red for flowering & fruiting (simplistically speaking)

I think that "Daylight" bulbs feature quite well in the blue spectrum?

Wife won't let me have a whole room of plants. Alocasia, Colocasia and many shade plants will grow happily in about 2000 lux. Just measured using the lux meter and the 11w daylight (6400k) bulb is 2000 lux at around 40cm

That sounds fine if you can have the light 40cm away from all your plants. Mine are spread 3m. When you take the inverse square law into consideration, the lux at 3m would be almost non existent.

Won't you have the same problem with LEDs? I thought they, like Fluros, had to be "almost touching" the plants for maximum benefit?

To get some canopy penetration you'd need Metal Halide or somesuch - which is hopeless for energy-efficiency

[Kristen]

What I really need to know is whether you guys think I actually need supplemental lighting in my conservatory. It is a very bright room with 4 white walls and a 3.5mx3.5m glazed roof. My main concerns are the Colocasia, Ensete v Maurelii, Super Dwarf Cavendish and a couple other tender Musas. Along with various Musa seedlings up to 8" tall and any possible Musa seed that might germinate. I guess the seedlings will have to go in the cupboard I used for the tomatoes this spring.

My two-pen'th is:

If you have some heat, such that plants could continue to grow, and the plants are relatively small (in my case "bought cheap, being grown on for next year"), then I think providing some light to keep them going, and growing, is a good idea. Provided you can afford it (and the cost of Light + Electricity is less than the cost of buying a decent sized plant in the Spring!)

If you are just over wintering then its a bit harder.

Folk here have convinced me that "some light" will keep the plants on tick-over. My worry would be that using "any old lights" may be throwing the wrong sort of light at the plants, so much would be wasted, and having the lights too far away from the plants (i.e. not having enough canopy penetration) could also just be wasting money on energy.

But Dave clearly has good results with just some ordinary fluros (albeit chosen for their light spectrum) and the odd angle-poised lamp to help out individual specimens.

But that apart, any conservatory is going to be "dingy" in Winter. My solar panels collect 10 x less energy in the Winter ... so I reckon that that supplementing the light is a good idea, provided the plants aren't dormant.

I have full blown, costly-to-run, Metal halide in the house for things I am brining on, and am now considering some CFL's in the conservatory and also a heater to keep it above +5C so they can make a little growth over the Winter, NOT go dormant, and be best placed to get started in the Spring.

[Vagetarian]

We are after what the plants need for photosynthesis - so Blue for vegetative growth, and Red for flowering & fruiting (simplistically speaking)

I think that "Daylight" bulbs feature quite well in the blue spectrum?

Absolutely, but a fuller spectrum is always better. Your point about emulating tropical sunlight and not British winter light shot down my point about the colour temps, in my last post I was really only talking about lighting colour in and around the home.

Won't you have the same problem with LEDs? I thought they, like Fluros, had to be "almost touching" the plants for maximum benefit?

To get some canopy penetration you'd need Metal Halide or somesuch - which is hopeless for energy-efficiency

You will have the same problem with any light source, including the sun. The difference with the sun is that it's so powerful and already so far away that a few more metres really is nothing.

I'm not pimping one technology over another, I'm making the point that an 11W CFL produces very little light (less than a 60W incandescent no matter what the packaging says). It will not grow a room full of tropical plants. To do that I would either need to dot several around the room or have one brighter source in the middle, either a large horticultural CFL lamp or a LED or a halide.

I don't know where you got the idea that metal halide is inefficient! Probably because they only come in higher wattage lamps whereas domestic CFLs come in very low wattages. Metal halide lamps are industrial flood lights! The truth is that MH is very efficient and is very close to fluorescent (lumens per watt), the difference is that it has the power to penetrate the leaves whereas fluorescent does not. I believe it also has a better PAR rating because the colour spectrum is better suited for plants. (Remember, plants don't 'see' the same light that we see.)

[Vagetarian]

Ahhhh, you made another reply

My conservatory will be between 10 and 20 I guess, it's my dining room.

I am doing the same as you, bought a load of plants in the sales and trying to get them even bigger for next year. Also trying to multiply Canna rhizomes for a long bed next year. I will have a few permanent Musas in the conservatory in future which I will attempt to fruit, the SDC being the first. So I do need to work out how best to keep these plants growing.

I think that the most sensible thing for me, considering Dave has so much luck with the little CFLs on a small scale is to hang a few of them around the conservatory.

I have a 220W PLL tube fluoro fitting for bringing things on, I got it instead of a halide because of heat. Your halide is superior and will grow better plants.