A tomato seed is the botanical structure capable of reproduction, representing the beginning of a new plant. These small, flat structures are found inside the tomato fruit, suspended within the pulp. Their appearance changes significantly depending on whether they are freshly harvested or prepared for long-term storage and planting. The visual characteristics of the seed provide clues about its maturity, viability, and readiness for cultivation.
Appearance of Fresh Tomato Seeds
When a tomato is sliced open, the seeds appear encased in a translucent, gelatinous coating known as the aril. The aril is typically clear or very pale green, giving the seed a slick, wet, and slightly slimy feel.
The primary purpose of this gel sac is to prevent the seed from sprouting while it is still inside the tomato. It contains chemical compounds that act as germination inhibitors, ensuring the seed remains dormant until the fruit fully ripens and decays. In nature, the gel breaks down through fermentation after the fruit falls, allowing the seed to germinate when conditions are right.
Appearance of Dried, Viable Seeds
For a tomato seed to be stored or planted, the surrounding aril must be completely removed, resulting in a distinct visual transformation. Once cleaned and dried, the seed takes on a firm, pale coloration, ranging from light tan to pale yellow or light brown. A healthy, viable seed in this state will appear plump and robust, not shriveled or dark.
The cleaned structure is relatively flat and small, generally exhibiting an oval or teardrop shape with a slight point at one end. The seed coat, or testa, is covered in fine, hair-like projections, giving it a slightly fuzzy or spiky texture when viewed closely. This characteristic texture is known as pubescence.
This fuzziness is thought to help the seed anchor itself into the soil. The hairs can trap moisture and fine soil particles, which helps secure the seed in place after planting. This rougher, matte texture replaces the smooth, glistening appearance the seed had when fresh.
Size and Shape Variations Among Tomato Types
While the fundamental color and pubescent texture remain consistent, the exact size and minor shape of the seeds vary depending on the fruit’s variety. Generally, the size of the seed corresponds with the size of the tomato it came from. For example, seeds harvested from a tiny cherry tomato are noticeably smaller than those found inside a beefsteak variety.
Cherry tomato seeds are petite, often measuring around 1/8 of an inch. Conversely, seeds from large slicing tomatoes, such as an heirloom beefsteak, can be closer to 1/4 inch in length. The overall shape remains a flattened oval, though some varieties may have seeds that are slightly more elongated or rounded than others. These minor differences reflect the genetic diversity within the thousands of existing tomato cultivars.