How do you tell if a female plant has been pollinated? — John
Shortly after a female flower has encountered male pollen, it will begin to shift over its efforts from expanding bud growth to producing seeds. The bracts will begin to swell and the white hairs will quickly start to turn red and then shrivel up. Soon after, the swollen calyxes will open and a seed can be seen protruding from it.
Pollination and seed production can only occur in the presence of male pollen (or a female hermaphrodite that produces pollen), so its important to limit exposure to males and hermaphroditic plants. Check your plants for signs of male flowers often, especially during the first three weeks of the flowering period. Kill all males or hermaphrodites with extreme prejudice as soon as they are discovered unless you want a harvest riddled with beans instead of buds.