Root trainers

Hi,  I am using 5" root trainer pots what is the best seed growing medium to use?  I am using John Ennis seed and I am finding it just pours through the large hole in the bottom and the soil level keeps sinking after watering and taking the seed with it.

Mike.

I had that problem too so i used multi purpose compost halfway and then sowing compost for the rest.  Just had to be careful to pick out all the twigs and debris from my cheap MPC or else it created a blockage.

Just to say I have been using rootrainers for many years now and a general compost will suffice.
Fill the trainers to the top, give them in the rack a sharp tap or two which settles the compost, some compost will come out at the bottom, then either add more compost if you are sowing small seed or in the case of beans place the bean/pea seed in and then top up with more compost. Keep moist as they dry out quickly.