Whether planting seeds of shrubs, trees, vegetables or flowers, all seeds share certain requirements for proper germination. Understanding the basic needs and principles behind seed biology and growth can help gardeners provide the best growing environment for their future seedlings.
The Right Temperature
Seeds have an internal mechanism that triggers growth when the seed is in the correct temperature. That temperature varies by plant type. Some seeds will grow immediately upon being placed in the appropriate level of warmth. Other seeds, such as many types of nuts, require stratification, which involves a period of cold temperature that mimics the winter, followed by warmth which triggers the seed to leave dormancy.
Dry seeds are metabolically inactive until given water. Once watered, moisture enters the seed cells and activates its stored enzymes, which converts the seed's starches into sugars to feed the young plant. The moisture also triggers a range of activities, including the activation of the seed's mitochondria and protein synthesis, and begins the process known as germination.
Some seeds can sprout on the surface, such as on moist paper towels, a seed-sprouting tray or a substrate product like vermiculite. Most seeds must be buried to a particular depth for proper germination and development. Seeds may be planted in soil or in a sterile soilless mix. The proper depth for appropriate development varies by the seed type. Some seeds are sown shallowly at a depth of less than half an inch, while others should be buried an inch deep or deeper.
Light is typically not required for seeds to start sprouting; in fact, some seeds require darkness to germinate properly. Once they have germinated and generated a shoot with small leaves, the seedlings require light for photosynthesis. Without light, the seedlings will quickly die.