How do you mend a bucket with straw?

In the song "There's a hole in my bucket" Lisa advises Henry to mend the hole using a straw (which is, of course too long, has to be cut by a knife which needs sharpening on a stone that needs to be wetted with water which has to be fetched in a bucket and so on round and round). The question is, how do you mend a bucket using STRAW? Water comes out through straws, they fall out of the hole anyway, if it gets wet straw goes mouldy - what does Lisa think Henry is going to do with the straw?