Text wrap for plot titles

try adding "\n" (new line) in the middle of your title. For example:

plot(rnorm(100), main="this is my title \non two lines")

You can use the strwrap function to split a long string into multiple strings, then use paste with collapse=\n to create the string to pass to the main title argument. You might also want to give yourself more room in the margin using the par function with the mar argument.