Welcome to the GardenAction forum. Feel free to post a message.
I used multi-purpose. I must say that last year, my Brussels Sprouts seedlings went the same way - doing well, then just collapsed. I was told to put them in a deeper tray for the roots to grow, which I did this year, and I have just planted all of them out this week. There is nothing that I can say really of what has gone wrong with your cabbage seedings!! A mystery indeed!!
I will try with seed compost and then if it goes wrong again I will buy some root trainer cells to see if it is the depth of compost that is the problem.This happened to me last year aswell but I am new to growing my own so I put it down to not knowing what I was doing,obviously learnt nothing in a year!!
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.
Hope this helps?
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.
Be sure not to over water. We all have a tendancy to water too much. Summer sqaush and cucumbers damp off quickly also.