What constitutes an heirloom vegetable or tomato? A romantic tale, often. Emigrants to North America could only bring their most precious belongings when leaving their native towns and villages for the voyage ahead. For many the luggage would contain the seeds of their most-favored plants. From these seeds grew the unusual varieties that are today known as "heirlooms".

In the grocery store, we typically see the cosmetically enhanced cousins of heirloom tomatoes -- the hybrids and genetically modified breeds. Cross-pollinating various plants that show the potential for mass production produces hybrids. Modifying or inserting plant genes achieves similar predictability. The results are fruits that are cosmetically appealing and uniformly sized for mechanized handling. They may have durable skin for easy transport, and rot resistance for the lengthy lags between harvest and sale. Many are picked immature to minimize the chance of bruising, then are treated with ethylene gas to accelerate ripening. Flavor, however, is pretty low on the list of requirements.

Where can you buy heirloom tomatoes? Try your local farmers' market. Chicago's green city market is a great spot. The market is held every Wednesday morning on the southwest corner of Lincoln Park, just north of Clark and La Salle. If you are an online shopper try FirstPicked.com; they can set you up with from one to a hundred pounds.