I'm in south east London, England. Ive seen so many different mixes of soil type for bonsai trees too, does it matter right now what I replant them into?

If you are going to keep it potted (and not in ground) then it is better to get them into a good mix as early as possible. It does not have to be a specific bonsai mix but should be a well draining mix with good air porosity. Regular potting soils are notoriously bad for containers. I am not sure what you can get in UK. You can get an idea of a good container mix in this thread. Conifers do not like soggy soil at all. They are more like cactus in that way. But since they are seedlings now you should keep them just moist and when they are established they will prefer to be on dry side.

Glen I have the same exact kit I think, I went and tried for Red Maple and Birch as well but they are not germinating, only the Mugo Pine ones. I have 4 looking like yours and in the other pot, 4 dead and one looking like twice as big as the others. I am also wondering what to do. I have them under a grow light right now but I have no idea how to water them. I watered them a lot today and I really hope that doesn't KO them. So many of them died last week as they were 2 inches tall and I don't remember if it was from overwatering or underwatering. tropicocancer, thanks for the advice. I would pot them up into a larger pot with proper soil but then won't this current soil be bad, even inside some good soil? It's 70 F in my house so I'll wait until it is 70 outside and bring them out.

Seedlings at this stage are vulnerable to fungal problem called damp off. The stem rots close to the soil and the seedling dies. So it is important to not over water and yet keep them from drying out completely.

Seedling at this stage do not have much roots or much soil sticking to the roots, so it is OK if a different soil mix is used. I would not disturb the root ball too much while transplanting and blend in a bit of the new mix.

I start most of my seeds directly in 511 mix with may be a thin layer of peat or bark fines on top. I only mist the top a bit during germination. After germination I am more careful in not keeping the top wet.

Gently introduce to them to outside while it is still cool like 50's You might to have keep them lightly covered so the leaves do not struggle and wilt. Keep in open bright shade for a while.

Thanks for the advice TOC. I made a new batch of seeds today. Tried several different combinations of soils to experiment including only Turface, only gritty, etc..

Plant some of those seeds in another pot and keep them outside if you can. That you can compare how they fare.Keep them a bit protected from wind and you should be fine.

I do not start from seeds these days except some tropicals and veges. But I bet you will see a difference in robustness of those plants grown outdoors.

Okay I'll play:

3 dead on the right, one dead on the left (put something like 5 seeds in each pot) let's see if that overwatering I did will take these out or not, the one to the right seems more robust than the rest and it looks like it has a second set of needles already grown, don't think I'll water until at least one or two weeks from now, then maybe put them outside if they show strength

Those seedlings that have keeled over is a classic sign of fungal damp-off problem. Pull them out and if you have any fungicide use it. If nothing sprinkle a bit of cinnamon powder which has anti-fungal properties.

I have hydrogen peroxide and cinnamon powder, which one is best? For some cuttings that got the damp-off problem I used 50/50 water and hydrogen peroxide in 2 sprayings it took care of it (along with removing the mini greenhouse plastic bottle tops for more air circulation).

Sorry. I did not see your post for some reason. I am a bit cautious with peroxide and never really use it on plants or soil. I may wet the soil with undiluted household peroxide before planting anything. I also use it to wash seeds before storing. I have read scientific articles that cinnamon has fungicidal properties and so I suggested that you sprinkle them on soil. I have not used it myself. I have used it on some seeds for temporary storage in the fridge when the seeds need to stay moist for viability. The only fungicide I use is a copper based fungicide for fighting mildew and blight on veges in summer.

Okay TOC. Weird that I don't have cinnamon in the pantry, gotta get some.