Originally posted by Trakehner:

Originally posted by MrFroglin:

It takes ~3.5 in-game days to grow an onion, and ~3.5 in-game days to grow a seed onion, so, unless you have mods, I can't see how you could have achieved that.

9 seeds after 7 days. 27 seeds after 14 days. 81 seeds after 21 days.

That roughly matches what jonnin said, and corresponds to my experience too.

Well I did. Take into account it depends on the size of the field you are planting in too. Mine isn't a very big field.

Well, yes, if you are only aiming for 3 plants (or possibly 9 if you are particularly lucky), then you can do it. However, jonnin was talking about 50 plants, which can't be done, from 3 seeds, in 5 days.