High Quality Content by WIKIPEDIA articles! High Quality Content by WIKIPEDIA articles! An heirloom tomato (also called heritage tomato in the UK) is an open-pollinated (non-hybrid) heirloom cultivar of tomato. Heirloom tomatoes have become increasingly popular and more readily available in recent years.Heirloom tomato cultivars can be found in a wide variety of colors, shapes, flavors and sizes. Some cultivars can be prone to cracking or lack disease resistance. As with most garden plants, cultivars can be acclimated over several gardening seasons to thrive in a geographical location through careful selection and seed saving.