if i draw outside air into my grow room is there any need for c02? and cany you grow a plant as big or as small as you want before its flowered. i have some 6 week old plants that will be ready to flower soon but i also have some 2 week old plants in the same room. should i just wait till alll the plants are atleast 8 weeks old to flower? or flower some at 4 weeks? and my only fert is fish emulsion. should that need flushed prior to harvesting? and i aquired a salvia clone, can those be grown on 24 hour light like weed?