i don't even know ware to start.... ok first off, just becouse you have a plant dosent mean its going to yeild X amount.... there is an equation for figuring out your yeild, first off, if your using florals to flower, i dout you will get a 4 ounces total... no matter how many plants... florals don't pack on the weight..... soo ok... it works like this, you get about 0.7 grams per watt of HPS light you use for flowering and that pretty good... the best growers get 1 gram per watt and thats working with a strain there formulure with..... IMOV the only thing florals are good for is early seedling growth... other then that your just pissin in the wind
i hate to have to be the one to tell you this... if you use a 400watt hps lamp, your going to get between 6 to 8 ounces, see like i was telling you before... X amount of light can produce X amount of pot...... the amount of plants you have.. or what kind they are really don't matter.. for the most part.. if your use a 400 watt HPS light and you fill a 3ft by 3ft area with pot you will get about 6 to 8 oz... weather you have 10 plants or 1 plant... the number of plants just dictates how much veggging you will have to do... you could veg one plant for a month and get 8 ounces... or you could veg 6 plants for 1 week and get 8 ounces, if you have a smaller setup, then do more plants vegged for les time... thats the better way to go... but to answer your queshtion... there is no way your going to get 4oz off a plant unless your using an addiquit light... if you use 400watts worth of florcents (not equivlant watts real watts) then i would think that you would get 0.1 grams per watt maybe 0.2... so that would be a total of maybe like 2 - 2 and a 1/2 oz... something like that... no matter how many plants you have
WATTAGE = WEED
if you are going to use florals i would recomend getting a t5, but for 1/2 the price of a t5 you could get a 400w hps/mh switchable ballast...
i hate to be real about this, but if you really want pot, you really need to get a light