Pot Marigolds, with their bright yellow to deep orange flowers, light up the garden from early summer into fall, under the right conditions. Although perennial, they are commonly treated as annuals, particularly in colder regions where their winter survival is poor and in hot summer locations where they also do not survive. Happily, they often reseed.  Start indoors 6-8 weeks before last frost or direct sow 2 weeks before last frost.  Cover with 1/4-1/2 inch soil.