I was wondering where this clever phrase came from and got some help from deadkytty9.

deadkytty9Feb 12 2007, 12:01 PM

From here:
“Since the early 1500s there have been similar expressions to
describe things difficult to find: “like finding a needle in a meadow of hay”
and “like finding a pin’s head in a cartload of hay.” In the mid-1800s the
expression became “needle in a haystack.”"

And from here:
“needle in a haystack – impossible search for something relatively tiny,
lost or hidden in something that is relatively enormous – the first use of this
expression, and its likely origin, is by the writer Miguel de Cervantes, in his
story Don Quixote de la Mancha written from 1605-1615. According to Bartlett’s,
the expression ‘As well look for as needle in a bottle of hay’ (translated from
the original Spanish) appears in part III, chapter 10. ‘Bottle’ is an old word
for a bundle of hay, taken from the French word botte, meaning bundle. Brewer
(1870-94 dictionary and revisions) lists the full expression – ‘looking for a
needle in a bottle of hay’ which tells us that the term was first used in this
form, and was later adapted during the 1900’s into the modern form.”

MythBusters had a clever episode on this. They suggested that if you really do need to find a needle in a haystack, try using a metal detector or other strong magnet, or throw the haysack in a swimming pool. The needle will sink, while the hay will float!

Source: This forum and Wiki