From the ArcaMax Publishing, Gardening Newsletter:
http://www.arcamax.com/news/gardening/s-2500-225943
To get the best basil crop wait until the soil has warmed to 65F to plant. Basil is very susceptible to chilling; if the weather's too cool, the leaves will brown and the plants wilt.
This news arrived on: 05/17/2008