January & February is when many gardeners begin to think about what they want to grow and start ordering their seeds.
Click here to see which seeds you can plant in your zone: https://www.seedsnow.com/pages/shop-all-seeds
If you are interested in starting plants inside, February is not too early to begin preparing for this. Expanding seed starting soil pods will will make starting seeds indoors much easier.
Here are some related links/blog posts that will help:
Getting Started: A Guide to Starting Seeds Indoors
How to Get Even Better Seed Germination
Tips for Successfully Starting Your Seeds Indoors
In March, in addition to starting plants inside, gardeners with cold frames (see season extension techniques) may use them either to start an early crop of greens (especially spinach) or to start plants like broccoli that will later get transplanted outside the cold frame.