Can you guess?  What I'm thinking of.

January 9th.  If your seeds need 8 weeks to germ - sowing the seeds now,  that's the second week of March.

Giving about 3 more  weeks to grow - repot into a larger container.  4 more weeks to grow into

a nice size - April 8th or 9th.  start to harden off.

Depending on weather, of course, and what type of plant.  You might begin to transplant into

the gardens mid - April or so.   JUST BE SURE to watch for FROST WARNINGS, you may

have to cover your new transplants.  

Nebraska can have killing frosts as late as Mothers Day.  

I'm always too anxious to wait until mid May to be planting bedding plants and have (from time to time) lost a few plants to cold.  BUT usually the bedding plants survive and thrive.

Have fun reading those gardening catalogues.