How many plants can you grow?

I have six gowing under two 400w hps and its tight. I feel if I trained my plants properly I would get a very similar yield out of 3-4 plants. Take it with a grain of salt, this is my first med-grow.

6-8 if goin natural, few more if lollypopping and loads if ur scrog,sog or lsting

I am doing sog under a 400w HPS. Fairly small space. If you go from clones and flip em as soon as they resume growth after rooting, using 2 gallon grow bags, I can easily fit 16 plants under my light. Thats 4 plants harvested every 2 weeks. I've grown them out by vegging longer, but honestly, 400w is not the strongest light, so keeping the plants short, makes it possible to keep more of the plant in the "good" light. Also shorter veg time means you will harvest more often. Greater number of small plants, harvested more often means more yield. If you want to go with a smaller container, say like a 2ltr coke bottle, you could fit way more plants in a given area!

I would say 9 tops.. but I too am a first time grower. I have 6 or so under a 400 and 250 side by side.

i kinda think about 100 watts per plant, it not scientific its just my general reckoning.