that potting mix really does not look good from what is shown, it looks just like fairly decent sized chunks of uncomposted pine bark with salt build up (either from the mix, your water, or fert if you are using it which you shouldn't be), possibly it's better underneath as all the bigger bits have come to the surface, but still not really what i'd call good in any way.
You'd be aiming for a finer more well drained, airier, sandy compost. Or preferably a seedraising mix (you'll notice these are fine and well drained, easy for roots down and veg to break the surface, which then can be moved onto a more sandy compost. Torsten has spoken a lot about coarse sharp sand and compost mixes over the years have a search.
Most potting mix is crap, even 'premium' ones, the industry needs a shake up and dont get me started on all the gardening shows floggin the shit, poorly composted materials with added fert yuk, and it's not really the best to start seeds in, getting away with potting mixes, even poor ones are more in the realm of plants/established seedlings with rootballs. I avoid them or add them as a small part of a mix.