March is the month for frost seeding.  This is the easiest work you will ever do on your food plots and should be done every spring on perennial plots.  The best time is when the weather is freezing at night and above freezing in the day.  Frost action, late snow and heavy rain will drive the seeds into the soil and get them into good contact with the ground. 

This is a great time to introduce new varieties of clover to your clover plots.  I like to mix varities that have different pH tolerance and maturation rates.

You can spike your plot with brassicas but only use hybrid types, not turnips for early spring. 

Put 1 or 2 pounds on per acre with a hand spreader.  Its a great way to get outside in spring, get some excersize and maybe even find a big shed lying around.