I have some basil growing in a dutch bucket (also called a drip system I think), and the leaves are curling down.

I've heard that this is evidence of over-concentrated nutrients. Even though the other vegetables in the bucket (1 broccoli, 1 lettuce) are not exhibiting the same leaf curling, I cut the fertilizer down by 50%. 1 week later, the curling is slightly worse!

Does anyone know what could be causing this? Or is this just the way basil is supposed to look?

Possibly useful information:

-I pinched off the tip of the plant so it would bush out. I believe I noticed the curling starting before I pinched, but am not positive.

-The plant was originally under a 400W HPS light, but was growing tall and skinny. So when it was about 3 wks old, I switched to a 400W MH bulb. Everything under the light approved of the switch. Still a bit leggy though.

-The plant is 7 weeks old. For the first 6 weeks, the nutrient solution was dribbling over the rocks 24 hrs a day, since I didn't have a spare timer (doh!). It now runs 1hr on, 1hr off, and off for the 8 hrs the light is off. This rate is only a guess based upon what I read somewhere about watering tomatoes in a dutch bucket. I'm open to better guesses though!