You can seed grass anytime between March and October but generally the weather is hot and dry June - August so seeding is often less successful. Seed over the summer months and you need to be very dedicated to watering the seeds every evening in the absence of rain.
Not a waste of time, no. DH We planted a new lawn two weeks ago and it's doing well; if anything I reckon waiting until September would be a bad move because plenty of daylight is needed for h new grass to grow.
Maybe what your DH is thinking of is heavy pruning and trans-planting, which are best done in the Autumn?
Hi, New gardener here, so sorry if this is really a stupid question. I need to plant quite a large area of grass in our new garden. I wanted to do it a couple of months ago but the ground wasn't ready. Now it is, but my husband told me it was a complete waste of time and that I should wait till September. Since it isn't at all warm at the moment and there is rain forecast this week (plus I'm on holiday soon so can water it frequently), is it a waste of time? Should I wait? Thanks