I use disposable plastic drinking cups and 3/4 fill with general purpose composting soil. 1 seed per tub. Water a little,frequently,keep in the green house. No problems. Have just planted out into their final postions.
Why use a seed tray then a pot and then into their final postion.
Least disturbance for any plant is better!!
I know you use more composting soil but it does get the results you want.
Thanks for all your replys,I have planted some more seeds into cardboard toilet roll middles then I can plant them with no root disturbance at all as they will break down in the soil.
Thanks again Keith.