Compost

Compost is wonderful stuff, but IMO it's better to use sterilised compost for seed sowing.

Not yet having much in the way of mature compost we have no option but to buy it in.

I've never really given it much thought before but after experimenting with a few different types over the last 12 months we've settled on a professional modular seed sowing compost with added fertiliser. Having used standard multipurpose stuff, peat-free, organic and John Innes types in the past, and blends of all of them, we're now really seeing the benefit of using the professional medium, especially for larger modules where the seedlings spend a bit longer in them.

My view is that buying a good quality seed compost represents very little outlay for the peace of mind it gives one at those important early weeks of growth. That said, done well, 'home made' unsterilised compost is full of beneficial microbes and other plant growth promoting bits and bobs that can give seedlings an equally good start in life!

I use multi-purpose (Miracle-Gro) and find it very good for both sowing and potting-on despite the fact that germinating seeds don't need much in the way of nutrients. They don't like being too damp either and MPC does better on that score than a soil-based one.