I'm so glad I found this thread. I'm also growing auto's. I grew auto's over the winter in Miracle Grow with a 90 watt LED and I was seeing what looked like nutrient burn on the leaf tips. Nothing too serious but it was there.

So now I'm doing auto's during the warm months. This time I have regular organic potting soil with no ferts added. You guys think I should just plant, water and harvest? I was thinking of adding some Osmokote as the label said it had 19% nitrogen. I was thinking high nitrogen was good. Also, I hear about CO2 a lot. I can get chunks of Dry Ice from the supermarket, put it in a styrofoam cooler and just run a very short dryer vent hose to the plants. With The weight of the CO2 it should slowly drift down to the plants. My auto' will go 9-10 wks. I'm also going to try my Aerogarden in tandem just to compare. I may also try some outdoor in tandem also. It's a learning experience. So far I've learned that LED's work and in very sub optimal temps too. I need to see what works best. Anyone have other thoughts on this? Also, I sent some seed to a friend in another state through US mail. Bad idea? or probably ok? whattaya think?