Inside my indoor garden, my compact fluorescent light fell from the top of the cabinet, and smashed onto the pot. Since its in a generally sealed container, can it be poisonous? and will it ruin my plants?

yes

5char

Dude, that sucks
sorry to hear that

Hmmm, they usually contain mercury which is unfortunate because they work so well for growing plants. Maybe you could mist it with some organic chelating agents then flush the pot with water...

I don't really think one bulb is going to hurt you but try not to let it happen again. You could build a wire case around it so it can't shatter anymore.. When you clean them up, you're not supposed to disturb the air so much because it can pick up the mercury and force you to inhale it if you're around it.

Well that's how I think it works, don't know why else they'd tell you not to use a vacuum.

If you managed to get every gram of mercury in you, the worst effect it could have would be similar to eating ~5kg of tuna.
The "dirtiest" bulbs have 5mg of mercury per bulb, and it would have started to evaporate right away. From there, im not sure how much is actually taken up by the plant, or if it's left in the soil. If you're still paranoid, just eat it, less than 0.01% of ingested mercury is absorbed by the GI tract, but what you should worry about the most is inhaling the vapors while you're cleaning it.

Just let it air out for a bit if you can, possibly with a fan on it in a warmer environment so the mercury evaporates.

Or start making hats.

if ur paranoid just get another light and when its finished growing just make some edibles and cannbutter

As stated above the Mercury is really what you'd need to worry about. I'd flush the plants ASAP to make sure there aren't any detrimental effects.

That really does suck though dude. How much did the light run you?