CFL growlight troubles

Last month I set up the growlight in my greenhouse to get some extra light in there in the evenings. It’s a 300w CFL lamp with an integrated ballast. As soon as I turned the light on it died with a loud “bang!”

I have only just gotten around to having a look at the broken bulb. Having opened it up, it’s obvious that two resistors are fried. I might have a go at replacing the resistors if it’s cheaper than getting a new bulb, but knowing why they went and whether it’s worth fixing would be great if anyone has the knowledge.

My first thought was that this type of light might not be suitable for such a cold and humid environment. It was probably about 15°C and 80% humidity in the greenhouse at the time. The bulb and fitting had both been stored for over a year in a cold dry garage.

Any thoughts or tips welcome. Should I buy a new bulb? Should I be looking at an alternative? Should I just give up on getting over 6 hours of light a day in the winter?

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Hello Hannah, usually the reason resistors burn out are due to capacitors going leaky (short-circuit) so look for a capacitor that is common to the 2 resistors and relace all components.
in terms of usable light, if you are only trying to extend the daytime (photo-period) then this should be ok, however if your are trying to drive growth (photosynthesis) with PAR light, then you would be better investing in a good quality LED bar that is specifically made for greenhouse or vertical farm use.
hope this helps.


Hannah, just realised your are probably from Nth America where the standard supply voltage is 110VAC and 60Hz, whereas the bulb is for 240VAC and 50Hz, so a big bang is to be expected?
I’m from Australia so we don’t have that problem.

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Thanks for the advice Graeme!

I’m in the UK. Our power supply is 230V and 50Hz.