Next morning, drain it and make sure the seeds are well spread out. Just leave it up side down at a counter in the kitchen. Don't even need to be next to a window. Then half a day later, filled it up with water and drain it immediately and leave the bottle upside down again. Do this twice daily.
By the forth day, you can harvest it. Either eat it straight away or keep it in the fridge. If you leave it in the bottle for another day, it will turn slimy and can't be eaten anymore. So I normally eats it on the forth day.
Not sure if it is me or what but those grown by me taste sweeter than the one I bought from the supermarket. First heard about it on t.v but not in detail so hubby and I search a few u-tubes video about it and start growing it ourselves.
Thanks for reading. Give this a try. It is easy and fun too.