Cannabis is an annual, so you can only harvest once.
GOD, I agree about growing many small, 25-30 cm single column plants that don’t restrict space yet still, fan leaves on any plants are unavoidable (unless the strain has been bred to have very few and smaller leaves) and it seems that the more plants you have, the more males you will end up with. In the end you only get at most half of the original plants in bud at harvest while the rest are of the masculine persuasion and only good for an extraction of what little cannabinoid’s they retain.
In my case, the number of plants is often halved by the time we sex them and if they were not headed in veg growth then we only have an unquantified amount of bud per remaining female which is often around 2-4 from 10 original individuals, making the entire process of caring for 10 plants a bit of a waste. Again it all depends on the growing location, how big it is and the genetics of the plants.
I have found that to increase the yield to an acceptable level, the plants must be of ample size with multiple bud bearing columns on them so to say that they are large is a good word to use in comparison to the size of the room. This is only because we mostly end up with a small number of individuals and that if they weren’t that large, the yield would be a waste of time, basically.
Really, the best way is to grow on constant light for about 2 or more weeks, head the plants, re-pot them, wait a further 5 days for the new heads to establish and then begin 12/12 for another month or more to make a SOG (sea of green) style bud plantation only taking up a tiny amount of vertical space, saving the need to groom individuals and creating the biggest fattest buds on a very short stock. This will only be achieved if you plant an excess amount to the desired amount of final females to allow for male wastage if growing from seed, but using clones would bypass this step completely and you could have a much faster and more guaranteed crop each and every time.
Any way you do it, cannabis growing is a rewarding and fun endeavour…
Peace.