50% of the nitrogen in our Country Estate Lawn Food is slow release although Nitrogen is only 22% of the total nutrients in the bag. I’m unsure of what the cooperative extension means by “30%”. Red thread thrives when we have a cool damp spring like this. They are correct, a shot of nitrogen usually clears up the problem. Our Country Estate Lawn Food should do the job and we also carry Espoma Organic Lawn Food which would also work. If you have a sprinkler system, that may also be contributing to the problem by keeping the lawn damp for extended periods. You should also do a pH test since acidic soil makes nutrient, including nitrogen unavailable to the grass.