I wonder if the application rate wasn't accurate when you applied it? First, the black spots are likely where moss has been arrested. Also, the product contains ferrous sulfate (usable iron), which in excess, can burn and damage a lawn and leave dead spots. The product also will not address emerging seeds--for that, one would need to use a pre-emergent to prevent the weed and grass seeds from successful germination--which might explain why you still have weeds.
The product does not contain a pre-emergent, so you may seed as soon as you like and before the temps exceed 85 degrees F. Try applying a starter fertilizer with your new grass seed-- I don't know if you have Scott's brand available in UK, but it would be my first recommendation since the nitrogen isn't so high it will burn your lawn. Also, scotts's has a weed and feed product that is excellent for dandelions and broad leafed weeds; if the brand is not available, you may look up the composition of this product online and find a comparable brand in UK. Good luck, and please feel free to leave me a shout if I can help. Good luck
The product does not contain a pre-emergent, so you may seed as soon as you like and before the temps exceed 85 degrees F. Try applying a starter fertilizer with your new grass seed-- I don't know if you have Scott's brand available in UK, but it would be my first recommendation since the nitrogen isn't so high it will burn your lawn. Also, scotts's has a weed and feed product that is excellent for dandelions and broad leafed weeds; if the brand is not available, you may look up the composition of this product online and find a comparable brand in UK. Good luck, and please feel free to leave me a shout if I can help. Good luck
