I think I have tried about everything under the sun to get grass to grow in my yard. Have tilled, fertilized and sewn several varieties of grass seed in the past five years with no lasting luck. Kentucky 31 mix and a Fescue seed were the last I used due to advice from my County Ag Extension Agent. Have used everything from commercial fertilizers applied per instructions, to using cow manure. No luck. My lawn will green up very nice after planting and slowly die out to nothing each time. It always gets enough water but it seems that the first places to start dieing is in the shadiest spots of my yard. I have several large oak trees surrounding my house and this problem just leaves me scratching my head. I have a sand/sandy loam yard with good drainage and ample water. I've trimmed all my trees back as far as I can without making them deformed. Any sound ideas?