A seed contains all the genetic characteristics of a plant. The genetic code contained within a plant dictates whether it is regular, feminized, auto-flowering, or auto-flowering feminized. Seeds are the result of sexual propagation, and contain genes from each parent, male and female.* Some (inter-sex) plants, known as hermaphrodites, bear both male and female flowers on the same plant. The genes within a seed also dictate a plant’s size; disease- and pest resistance; root, stem, leaf, and flower production; cannabinoid levels; and many other traits. The genetic makeup of a seed is the single most important factor dictating how well a plant will grow under artificial light or natural sunlight and the levels of cannabinoids it will produce. *See chapter 25, Breeding, for deviations from the above rule (i.e., in relation to inter-sex plants).
The genetic makeup of a seed is the single most important factor dictating how well a plant will grow under natural or artificial sunlight and the levels of cannabinoids it will produce.
All seeds have the same basic requirements for germination and seedling growth. Strong healthy parents, proper breeding practices, and excellent care will yield strong seeds that germinate well. Strong seeds produce healthy plants and heavy harvests. Seeds stored under ad- verse conditions (hot, cold, or humid) or stored too long will germinate slowly and have a high rate of failure. Vigorous seeds initiate growth within a day or two. Some seeds take longer to germinate. Seeds that take longer than a month to germinate might always be slow and less productive.
The cask, or protective outer shell, on some seeds never properly seals, which allows moisture and air to penetrate. It also causes hormone concentrations to dissipate and make seeds less viable. Permeable seeds invite diseases and pests to move in. Such seeds are white, immature, fragile, and crush easily with slight pressure between finger and thumb. These are weak seeds that do not have enough strength to germinate and grow well.
A simple view of a seed exposes an embryo containing genes and a supply of food wrapped in a protective outer coating. Seeds range in size from small dark ones from tropical climates to huge seeds bred for hemp oil extraction. Mature seeds that are hard, beige to dark brown, and spotted or mottled have the highest germination rate. Soft, pale, or green seeds are usually immature and should be avoided. Immature seeds germinate poorly and often produce sickly plants. Healthy, fresh, dry, mature seeds less than a year old sprout quickly and grow robust plants.