I think you're kind of late for onions and carrots (depending exactly where you live).
Note that if you're in this general neck of the woods - this is an excellent gardening publication IMO (the print edition is shorter than the online edition but you get it sooner):
http://clay.ifas.ufl.edu/CONTACT/Con...eb_2013CCC.pdf
It costs $3/year (for postage) and will let you know about the planting seasons for just about everything (in addition to lots of other information). Robyn