75% of my back yard is bermuda grass sod. For some reason, the builder only sodded it to a certain point. The left over 25% is just pasture grass (looks like bayhaila sp?) It grows so much faster than the Bermuda of course. My question is what is the best way to get bermuda growing there? Do I need to wait until next spring to do this or can I do it now? Do I need to kill the bayhaila first and then spread the bermuda seed?