Tomatoes, like potatoes, are part of the Nightshade family, the Solanaceae. Though commonly thought of as a vegetable, the tomatoes we eat are actually the fruit of the tomato plant, a short-lived perennial usually grown as an annual. Like most fruits, they develop from the fertilised ovary of the flower and contain the seeds that can develop into new plants.
This sprawling, somewhat hairy plant is native to Central and South America and the southern part of North America. Tomatoes were cultivated by the Incas and Aztecs 1,300 years ago and brought to Europe by the Spanish conquistadors. The plant likes warmth but can be grown in North America during the hot summer months. Breeders have developed a wide variety of types, some early ripening for cool areas, some with extra large fruit and many with particularly good flavour. The lax, sprawling plants may be determinate, flowering at a certain height and then putting energy into fruit, or indeterminate, continuing to grow and flower until killed by frost.
The Tomato Flower
The yellow flowers are produced in clusters, and they open, are pollinated and set fruit sequentially, from the bottom to the top of each cluster. Each flower has petals that surround the male organs, the stamens that produce pollen which, in turn, surround the female organ, the sticky stigma that catches the pollen and the ovary below it. The fertilised ovary is what swells and ripens into the seed-containing tomato that we eat. If you cut a tomato crosswise, you will see the three sections of the ovary with the seeds attached to the inner wall.
Tomato seeds are large and easy to sow but need warmth to germinate so most home gardeners start with small plants from a greenhouse or nursery. These should be planted in good soil with added organic matter and lime if the soil is at all acidic. Leggy transplants can be laid on their side and the stem covered with soil after the leaves on that portion of stem have been removed. If you live in a cool area, give the plants as much warmth as possible for best taste. Experiment with a few recommended varieties for your area to find the ones that you prefer and grow well for you.
Saving Tomato Seeds
Hybrid tomatoes are hand-pollinated from choice parents, and any seeds you save will produce a wide variety of fruits, rarely much like your original hybrid. Heirloom tomatoes, on the other hand, are strains that come true from seed, and you can save and grow them year after year. The seeds must be freed from the pulp, however, before they can be dried and saved. One method of doing this is to allow the pulp to ferment for two or three days then wash the seeds and allow them to dry.