they actually have contests all the time for "party cup" grows, from seed to finish. having said that, while I always start them in these cups because they r ideal to guage watering at such an early stage, etc. I would never grow in it all the way through. u have to realize after a certain point, in a cup so small, u will have to add nutes (as the little bit of soil will be depleted very soon of nutrients) and growing mj is largely about them having enough root space as to allow for a bountiful harvest & healthy plant; even flowering the smallest of plants, ur going to be giving up yield because ur roots will be bound. again, it is done all the time, but I would never suggest it. is it really that hard to transplant into a suitable pot after a few weeks? no...