I have a client who wants to fill in his existing bermuda yard with seed. Mainly sand on the property about one mile from the beach.There are a few 10X10 areas that need seed. He wants to seed the entire yard. The coverage he has now is sparse in a lot of areas. When I seed new lawns I rake, seed. and cover with hay, water everydayand keep seeds moist till they sprout. Then I cut after a few weeks. I can't do this with his yard. If I let it grow for a few weeks all the existing bermuda will get too tall and will brown out when I cut . Enough water for the seed will be too much for the current lawn, any sugestions ?