Quote from IronMagus
I just did exactly that, and nothing grew. Well, not nothing. Baby cows grew up, but planted wheat and canes did not. I planted some wheat, some cane, and spawned in some baby cows in a pen, then I TP'ed 1000 blocks away on both axes, and planted some more cane there. I waited over half an hour, until all of the canes had grown at least once, and most of them had grown twice. Headed back to spawn, and nothing. Every single one is still only 1-tall, how I planted them. The cows had grown up, but the canes and wheat had not grown at all. Just as I expected. Just as it had been last time I did this exact same experiment, back in 1.3/1.4 or thereabouts.
I suppose it could be different in multiplayer. I don't have the ability to test this at the moment. Do you have links to the videos you mentioned?
I'm pretty sure the loaded spawn chunks only applies in Multiplayer, not ssp.