Seeds remain dormant until suitable conditions come together and trigger them to start growing. This germination is based on both the internal physiology of the seeds along with external or environmental conditions. Internal triggers are the age of the seed, it's food storage, health, seed condition, etc. But more important may be the external conditions........
1. WATER- Dormant seeds are dry seeds. They require a significant amount of water to soften the seeds and expose the embryos to moisture. As the seeds absorb the water they swell and break their seed coats. Food reserve in the seeds are activated by the water and provide nourishment for the seedlings.
2. OXYGEN (respiration)-Oxygen is needed for metabolism and energy. Seeds that are buried to deep, are planted in heavily compacted, or overly wet soil, will be oxygen deprived.
3. TEMPERATURE- The temperature of the soil at which seeds germinate can range from the low 20's to high 80's. If the soil temperature is to hot or to cold, then the seeds will have a lower success rate, a longer germination period or not germinate at all. Some seeds need to go through a cold snap or even the heat of a fire before they will germinate!
4. STRATIFICATION (preconditioning)- Altering the seed coat to make it permeable to water. This can be done by roughing up seeds or soaking them in water prior to planting. The seed coat is weakened making germination easier.
5. LIGHT-Most seeds will germinate in the dark. Some seeds need to be exposed to light for a length of time before they will start to germinate. There are some seeds that will germinate in both. Check your seed packet for light requirements and planting depth. Seeds that need light can be placed on top of the dirt. Seeds that need darkness should be planted 2 to 3 times their diameter, placed in darkness, or covered to block out the light (until germination starts).
There is nothing more exciting then seeing the seeds you have planted start to grow!