I am currently experiencing that my tall fescue/bluegrass lawn, 4 years old, is in need or repair from old thatch and minimul dead spots. It is also not so green as it once was when it was young. My plan is either hit the lawn with some ammonia mix or synthetic quick fertilizer OR plant some quickly germinating Perennial RYE seed. I do have some thin struggling areas in the lawn so new growth would help thicken up and bring the green if I planted Rye. Would germinate in about 3 to 4 days and the weather here is high 70-to a high temp of 81 and showers every other day. Not a bad time here to plant. The downside of planting the rye seed is I wouldnt be able to fertilize the yellowing grass for a few weeks. What would you guys do. The weather here is unseasonably cool and perfect so although it seems as if I am late in the season to plant, thats not an issue. Fertilizer and seed with both run about the same price and both are not a problem of time and or work involving their application.