Experimenting with Compact fluorescent lights (CFL)

I’ve made plenty of experiments with goal to find best light type for keeping mothers and young plants in vegetative state.

CFL’s I’ve tried were available in two outputs: 115W and 180W and two colors (three including combination of both) of spiral spectrum: 2100°K (flower) and 6500°K (grow).

I’ve used both power outputs and also experimented with flowering under 2700°K

More powerfull type:

Establishing new mother plants under CFL:

When using for grow phase, I’ve noticed that plants are more vigorous and branch really well. I believe that production of clones can be slightly increased with CFL. The problem I suspected is that light doesn’t reach into distance. I confirmed this suspicion by measuring lumens with light meter. So I’d say using CFL for large mothers is very impractical. And mother plants can grow pretty tall if you keep them for years :).

So I’d recommend to use CFL for vegging young plants before they grow to tall or before switching them to 12/12.

One thing really surprised me and that was short operating life of these lamps… It starts with if you are lucky enough that DHL delivers the lamp in OK condition… There is about 50:50 chance that the lamp won’t make it to you together… It is extremely fragile, so you have to be very careful when inspecting the light, moving it and handling it around your grow room. And if you don’t break it yourself, rest assured that it will stop lighting very soon… I’ve got about 20 of these and 5 of them made it to second year (they were not lighting 24/7). Practically every month one of them ceased working…

Summary: Usability for Vegetative Phase

For vegetative state my opinion is that CFL when compared to MH (metal halide) offer slightly better branching, but light distance is very limited.


Two rounds were done also to test flowering. CFL 180W 2100K SON-T Spectrum lamp (with integrated ballast) was hung vertically for kind of “vertical screen of green” setup. Footprint cca 60x60 cm.

Afghanica strain from Flying Dutchmen (now nonexisting seedbank, later acquired by Sensi Seeds). Yield of this phenotype is usually above average.

Sorry for missing photo of whole setup, there are 8 plants around the lamp Sea of Green style, switched to flowering at 30 cm height (finished 60cm tall). Plants are in coco, fertilized with Biogreen (mineral based nutrient)

Buds are kept away from lamp using screen. At 5-10cm from the lamp I measured 40.000 lux

Resulting yield was 90 grams.

Summary: Usability for Flowering Phase

CFLs can’t match lumen output of HPS lamp at the same watt output. But they emit really low levels of heat which makes it suitable for limited space closet grows (specially in vertical setup).



I also tried to CFL grow. With scroging (if you do not mind, I can show it here)… but light scattering was not ideal and also I think about Vertical growing.

So thank you for inspiration. Just Im scared of the “life” of lamp. I got her one round. Lighting around 3 months. I hope it still holds… at least a year.

Scroging method is the future :green_heart:

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sweet dude. i used to run cfls only when i started indoor gardening. bought a 125w sunblaster 6400k about 4 years ago and it still works. never had a problem. veg growth is still awesome with it! i pulled 3.2oz from a bc kush plant in a 25gal garbage can in a closet with no ventilation and very little skill. ive always loved cfls. but for now. im in love with leds fosho!!

Much love

If you are very very careful, maybe they can live longer :)… from my batch only one survived till now :)… some of them failed electronically, some of them only partly (e.g. one tube died others still shine) and some have been broken by careless manipulation.

One more shot of mother vegetation room with CFLs…

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Nice! I use them sometimes but mostly for another species :slight_smile: In Cannabis growing they are useable on babies and seedlings. Then in bloom phase in some untrained crazy budding ladies with unusual grow pattern. Then you can place red CFL¨s along with your classic flower lights to cover some “blind spots” because of they are not too hot so you can hang some inside the bush… Basicaly I agree with you about CFLś.

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In my 2x2x4’ veg box I built an arrangement of 4 sockets with splitters and run 8 23W (100W equiv) 6400K Daylight CFL’s . According to my calculations this draws 184W of power giving 800 equivelant watts of light and 12,500 lumens with each bulb at 1600. The bulbs are good for 10,000 hours so I run for 18 months but smarter to change every 12 for $15 I have only been running this for a month so far but seems to work quite well.

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Yes CFL work very well for vegging and are useful because of their spectrum properties (I wouldn’t use anything else than fluorescent tubes for seedlings/clones - specially I like those rare aquarium 10.000°K /should be cool white like high mountain sun/).

But honestly (no offense) I don’t believe that “equivalent” marketing which we can see on household fluorescent/CFLs nowadays. It means equivalent of incandescent light (light is emitted as a result of heat). When you consider light output of industry standard - HPS 600W - you arrive at roughly 90.000 lumens => 145 lumens per watt (overhead taken into account). Your calculation is 12.500 lumens / 184 watts => 68 lumens per watt. From this comparison the advantage of HPS and HID lamps is clear.

No offense (it is about the strategy of cfl producers), I just want to put the numbers into perspective.


Thank you. I agree about the HPS being more effective but I already have a 600W HPS on the same circuit and current draw is my biggest concern. I could maybe go with a 250W for the 2x2’ space but even that small increase could be detrimental to the circuit. I totally believe in a large safty factor lol

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I strongly agree from my experience.I prefer CFL due to low excess heat and better branching.It´s easier to keep air in motherplants room moisty enough.Also it´s cost effective. Which manufacturer is the best in your opinion? From my experiments I must say, that Electrox is shit(too much excess heat and shit spectrum). Plug and grow was better but I hoping for return of the king to our market - R.I.P. Nurturelight :frowning: Did you test Agrolite or Maxibright(still available only in Britain I think-their spectrum looks realy good in the charts)? Now using cheap Feliz and surprisingly it works good enough yet, although is not the best I used.I am thinking of upgrading from 125w Feliz to Agrolite 150w but i need some references first.

Yes there can be slight differences between lights regarding the spectrum. Myself I haven’t tested more than like two brands but with pretty similar results. Both were manufactured in China :slight_smile:

Also it is better to measure watt output yourself, you can’t believe those Chinese markings :nerd: to make sure you compare apples to apples.