(Sacramento, CA)  --  Many of California's farmers fear the ongoing drought will likely force them to let hundreds of thousands of acres sit idle.  And less supply, they warn, will send food prices skyrocketing.  The hardest hit crop will be lettuce, which takes three-and-a-half gallons of water just to grow one head of the leafy green.  Lettuce prices could jump by 28-percent, followed closely by avocados.