i dont see why they would burn... but if you are worried... i mean just make a mix equal parts aeration, compost, and peat. you can't go wrong. they need so little when they are small like that.
this thread is full of some very good advice!
An easy way to check to see if your soil is too "hot" is to plant another garden plant in it and observe. Within three days or maybe five at the most, you'll see either the plant take off, or not.
another easy way to make sure is to cut that mix 50/50 with pro mix or something like that.
Usually too "hot" really means not aged enough, but "hot" is a generic term, I've even heard growers use that to describe acidity (albeit incorrectly)
In my world, too "hot" is referring to nitrogen, more specifically the readily available kind, like urea. Or in some cases the water soluble kind, guanos, blood meal (kinda), fish emulsion, squid emulsion, those types of things.
In my experience, I've never, ever, ever, burned a plant from organics, BUT I am a notoriously light feeder, I mean I did "water onlys" for bagged soils on numerous occasions.
The key to it all, is to mix all your nutrients in with your compost, and let in age. It's not hard.
Make two batches of soil, one that's aging and the one you are using. After harvest plant legumes to live and die through the winter, they compost, and by the time your compost is ready, you add in with your old soil, repeat as needed.
Make an amended leaf compost every autumn. And by early spring if you did it right your compost is done.
It's actually pretty damn cool, the seasons tell me when to add more leaf compost.
I've done three runs without amending, and haven't seen problems.
Other than soil compacting.
SO three runs happens to be the approx. time between reamending.