John Innes seed compost. Some of the more fibrous composts seem to invite trouble.
Verve (John Innes No 1) Seed Compost from B&Q - this year I've had an almost 100% strike rate.
Which? also recommended the Verve multi-purpose compost as being just as good as a seed compost, and much cheaper. I have used it for my tomato and some flower seeds, with good results so far.
I just used all pupose compost and sifted it a few times - got in there with my hands and spread it around in a large sifter over a pot and picked out the few small stones.
Almost all seed packets and tips will say use seed compost or all purpose.I have had really good results.
I have used a John Innes seed compost & when that ran out I used Blue Diamond but I am not sure what the exact name of the compost is only that we bought it from the Blue Diamond Garden Centre. I mix perlite or vermiculite with the compost.
Aldi compost for seedlings - £1.49 a bag. It's good this year, hasn't been in previous years but appears much improved. Retains moisture well and my seedlings are romping away in it.
I AGREE with zoomer I have used aldi seedling compost and good results .
Verve 'John Innes' Seed Compost from B&Q. Almost perfect strike rate on seeds.
JI for me too, but it does vary a little, depending on the quality of the loam used.