The tomato is botanically classified as a fruit, specifically a berry, though it is often treated as a vegetable in the kitchen. It is the plant’s reproductive vessel, developed from the flower’s ovary to house and protect its seeds. The number of seeds contained within a single tomato is not fixed. The amount of seed material varies enormously, making the count a complex biological question.
The Typical Seed Range
The number of seeds found in a single tomato is highly variable, depending on the specific variety and the fruit’s size. A medium-sized, standard globe tomato typically contains a seed count ranging from 50 to 150 viable seeds. This range represents a functional average for common varieties found in grocery stores and home gardens.
Smaller types, such as cherry or grape tomatoes, often contain the lowest seed counts, sometimes holding fewer than 20 seeds. Large beefsteak varieties, which are bred for maximum size, can contain 300 or more seeds.
Factors That Influence Seed Variation
The variation in seed count is fundamentally driven by the fruit’s internal anatomy, particularly the number of locules. Locules are the jelly-filled seed chambers within the tomato, and a higher number of these chambers directly correlates with a greater potential for seed production.
Smaller, elongated varieties like plum tomatoes tend to be bilocular, meaning they have only two seed chambers, resulting in a lower seed count. Conversely, large heirloom tomatoes are often multi-locular, possessing many small, irregularly shaped chambers that hold a significantly higher quantity of seeds.
This difference in internal structure is a key distinction between modern hybrid varieties and older heirloom types. Many commercial hybrids are selectively bred to have fewer locules and a thicker wall, which reduces the overall seed and juice content.
The success of the initial pollination and subsequent fertilization also plays a direct role in the final number of mature seeds. Each ovule within the locule must be successfully fertilized to become a viable seed. Environmental factors like temperature, humidity, and the presence of pollinators influence the efficiency of this process. If pollination is poor, a tomato may still develop, but the number of fully developed, viable seeds inside will be lower.
The Botanical Function of Tomato Seeds
The tomato is a simple fruit, a fleshy berry that develops from a single ovary, and its primary biological purpose is seed dispersal. Each small, flattened, kidney-shaped seed is encased in a protective, gelatinous sac known as the aril, which is derived from the placental tissue inside the fruit. This aril protects the embryo and plays a role in regulating germination.
The moisture and chemical compounds within the aril actively inhibit the seed from sprouting while still inside the ripe fruit. In nature, this ensures that the seeds only germinate after the fruit has fully ripened, fallen, and decomposed, or after passing through the digestive tract of an animal.
For gardeners interested in seed saving, this natural inhibition must be overcome by a process called fermentation. Fermentation involves placing the seeds and pulp in a small amount of water for several days, which mimics the natural decay process. The beneficial bacteria break down the gelatinous aril, cleaning the seed and removing the germination-inhibiting substance. Once the aril is removed, the viable seeds sink to the bottom, where they can be collected, dried, and stored for future planting.