What is heirloom gardening?

An heirloom plant, heirloom variety, or (in the UK) heirloom vegetable is an open-pollinated cultivar that was grown during earlier periods in human history, but not used in modern agriculture. The trend of growing heirloom plants in gardens has been growing in popularity in the Us and Europe over the last decade. This is called heirloom gardening. Some examples are heirloom tomato, forbidden rice and Bhutanese red rice.