This is called phenology. And low and behold, there is a lot more value in this interdisciplinary science - various plant phases can be monitored over time - as one way to understand climate change. Here is a definition from this national website: Phenology is the study of recurring plant and animal life cycle stages, or phenophases, such as leafing and flowering of plants, maturation of agricultural crops, emergence of insects, and migration of birds. Many of these events are sensitive to climatic variation and change, and are simple to observe and record.
Here in my zone 6a garden snowdrops are a sure sign of the ground warming up. Another sign is the witch hazel tree, which has these amazing blossoms. If you don't know what a garden zone is, check out the map at the US National Arboretum (it includes Canada too!).
How to start seeds:
There are many many great resources out there with good "how to" advice. I'm including a link to Renee's Garden - great seeds and informative website and blog because I like her product and company profile.
