Janet Tweedy writes
In article , WaltA
writes

Hmmm, you want 12 bags though ,, not sure about that, have you got
some energetic helpers ? and a steam sterilizer ?
(I use a spare microwave for my modest requirements these days, even
so, - small lots frequently - soon gets a lot done ! )


Not sure even my microwave can get through 12 bags
I have often thought of mixing my own compost but never actually got
round to amassing the right ingredients. Usually I get seeds then dash
out into the garden to find some compost to sow them. The only thing I
try to do is use really clean pots or trays and use clay pots for seeds
that take a long time to germinate.

Why clay pots?

I usually put long term seeds into plastic trays inside a sealed plastic
bag, because otherwise I always forget to water them. That's what I'd be
afraid of using clay pots.

I did think of doing what was often done in propagation which is to sow
into a surface layer of seed compost but have a 'stronger' mix for the
bottom layer so if the seed don't get potted up quickly enough they
will have some food to get on with.

Would that work at all? Does any one know?

Wouldn't the higher nutrient of the stronger stuff in the base simply
leach upwards? Would it be a problem if it did?

How deep is your pot or seed tray for this? Even an apparently tiny
plants can have an extensive root run, which in a seed tray just goes
sideways and gets tangled in all the other seedlings (speaking as
someone who doesn't always pot on as quickly as I should)
--
Kay