Hagrid is a character in the Harry Potter movies and he lives in a house that looks just like the little pointy roofed building in your garden.
Jake also said you have a bucket drier in the middle of your yard
To explain to the others why this is funny, Bert has an EQ mount in the middle of his yard and to keep rain off it he has a large bucket, tipped upside down, over the head.
Jake thought it was a thing to put a bucket on so the bucket can dry!
Kids. Don't ya love em!