Raising seedlings can be done directly in the garden, or in pots or seedling trays, depending on the local climate, available options and intended use of the seedlings.
The key factors that affect seed germination are:
- Oxygen - there is no root or leaf system to breathe, so oxygen must be able to reach the seed. A light porous soil helps. The main thing is not to bury them in a hard clay soil, or bury them too deeply within the soil, or have a soil which is waterlogged, or the seed may die.
- Temperature - many seeds prefer a temperatures around or slightly above room-temperature, 16-24 deg C (60-75 F) - this applies to most food plants which are commonly grown. (Other plants have more unusual requirements, but you generally won't encounter these when growing vegetables or herbs. Some cold-weather plants can germinate just above freezing. Others response to changes in temperature between warm and cool. Some seeds need to be exposed to cold temperatures (vernalizationW) and then be allowed to warm up, to break dormancy. Some seeds only germinate after hot temperatures during a forest fire which cracks their seed coats.)
Hot, cold, wind, pests excess sun can threaten seedlings.
Create the environment
Check your setting for the threats above, and look for ways to minimize them.
Notes and references