I don't grow outdoors, just indoors. A 10X10' area is 100 sq ft. Indoors, you can grow a plant for every 1.5-2 sq ft. Some people even say you can grow 1 per sq ft. 100 sq ft will accomodate the 99 plant maximum in Cali. I wouldn't try more than about 70 plants, but I like a little space to work.