I'm a novice gardener but undertook the job of seeding a new lawn as so:
Rotivated 2 areas around 50 square metres each which has old grass on, applied pre-seed fertiliser, sprinkled seed as instructed, laid top soil over and gentle rolled over it. Since this was back early to mid March and was nice weather and hosepipe ban was not in force I did water it every morning and evening without drowing the seed.
The grass grew in patches but I'd say overal only 35% of the seed has grown through and since then obviously we've had nothing but cold weather and rain.
The topsoil I used was from a company in London that provides organic fertiliser as well, this top soil looked more like fertiliser but when I challenged them they said it was a special mix, should it stop the grass growing even if it were?
The only other explanation is birds???? but I put a lot down and can't see birds eathing that amount, maybe overseeding was an issue? Or maybe too much top soil (approc 2cm).
I have spent a lot of time and effort and would love to hear from someone who has some advice.