seed

In agricultural practice, a seed is any structure a grower plants to produce a new crop plant. The term covers true seeds (the ripened ovule containing an embryo and endosperm), but also extends to seed potatoes, tubers, bulbs, and cloves because functionally they serve the same purpose: they carry the genetic material and stored energy needed to establish a new plant from dormancy. A sunflower achene, a carrot umbel fragment, or a garlic clove all count as seed in the field, even though botanically they are distinct structures.

True seeds, the most common type in commercial agriculture, consist of three parts: the coat (testa), which protects against disease and damage; the embryo, which will become the root and shoot; and the endosperm, a starchy or oily mass that feeds the seedling until it establishes photosynthesis. Seed size ranges from dust-fine lettuce seed (500,000 seeds per kilogram) to large beans or grains. Oil content, germination temperature, and dormancy characteristics vary widely. A maize kernel germinates quickly in warmth; a winter cereal may require a cold period before it will sprout.

Vegetative propagules, potatoes, yams, ginger, tulip bulbs, strawberry runners, are called seed when sold for planting, though they contain no true seed. A seed potato is typically a whole tuber weighing 40 to 100 grams, cut into pieces weighing 20 to 30 grams if large seed potatoes are used, each piece carrying dormant buds. These materials bypass embryonic development and regenerate an identical genetic copy, which matters for maintaining specific cultivars and avoiding the segregation and weakness that can occur in true-seed crops over generations.

Seed Quality and Handling

Commercial seed must meet germination standards, typically 85 to 95 percent for field crops, verified by testing laboratories that count sprouted seedlings after specified incubation periods. Seed is rated by purity (percentage of desired species by weight), moisture content (often 10 to 13 percent for storage stability), and vigor (speed and uniformity of germination under stress). Fungal and bacterial contamination is managed through hot-water treatment, chemical dressing, or both. Storage conditions matter acutely: most seed keeps longer in cool (4 to 10 degrees Celsius), dry air; oil-rich seeds spoil faster than starchy ones.

In the trade, seed sits at the intersection of genetics, logistics, and regulation. Farmers either save seed from their harvest, buy certified seed carrying disease-free status and varietal purity guarantees, or use hybrid seed that must be purchased annually because progeny do not breed true. Seed companies maintain breeding programs, multiply stock in controlled environments, conduct germination and purity trials, and handle paperwork for phytosanitary certificates when crossing borders. The choice between saving seed and buying it turns on economics, regulatory risk, labor, and the cost of genetic improvement.