Seedling starting soil without buying stuff

I would really like to know if anyone of you permaculture heads know a great seedling soil build method.  The hope is that i can do it so that it can perform  just as good or better than the store bought stuff.  I know time is often a big part of any building process and i figured this year was the year to get that ball rolling.   I am curious if this is even possible with what i have on the farm?  Or is simply doing the 1 part peat, 1 part perlite, and 1 part compost the best often used method?  Id almost hope i could negate the unatural ingrediants like perlite, and unsustainable peat.  I operate a CSA and do some market gardening to make ends meet.  So i mean business.  Thanks in advanced to any of who contribute ideas or suggestions.

Leaf mold. Go into a heavy thicket. Pull back the leaves and get what is underneath.

My Grandparents had a greenhouse and they always made their own seedling starter mix. I still carry that tradition on.

We have old growth forest here that has never been cleared for fields...like ever, so I use that soil, and mix it in with my sheep manure. Sheep manure is great because it does not burn seeds like other manure, yet is high in NPK. Here we have a seaweed factory that makes carrageen. and so I can use that as a makeshift perlite. It has a lot of micronutrients in it too.

I mix all this up in my cement mixer, a tool I use more for mixing other things than concrete!! It works great! You can buy some really cheap ones that Harbor Freight that hold up well I am told. I highly recommend it as mixing is where all the work is.

The trick is to do all this in the fall, digging out the soil and screening it over hardware cloth to take out the rocks. Then mix it up before the ground freezes. That way in Feb when the blizzards are cranking outside, your little seedlings are in some super-great soil, merrily growing away in the greenhouse!

1 part peat, 1 part perlite, and 1 part compost the best often used method?

I've used something like this in very rough approximation for years without issue. In fact, I've never had an issue with my seedling mix so I've gotten lazier as time goes on and just mix whatever is handy. Usually some old indoor potting soil (made of coco coir, vermicompost and vermiculite), a bit of vermicompost, and sand as of late. I've also used soil from outside — our soil is very sandy. Pretty much the only thing that seems to matter is that it's well draining and screened to take out the big chunks.

I was lucky enough that I have access to a dilapidated barn on an old homestead where there was about 2 tonnes of cow manure that had been aging on cement for probably 10 or more years. Unfortunately I have exhausted most of that after 3 years, and like JADAM techniques and others have suggested, leaf mold will be my next resource.

This year I did potting soil, manure and sand in equal parts and added fireplace ashes to the mix when I had them. The sand seems to makes the plants healthier by allowing water and air to more freely travel through the soil, and the chance of damping off is reduced also. I have about 25 pepper plants that I transplanted to bigger pots and they came out of the smaller pots easily - not nearly as many injured tap roots as when sand isn't in the mix.

I always reuse soil from potted plants that died - dried and combined with shredded leaves and leaf mold, I'll sift out unwanted material like pebbles and small rocks and other bits that would prevent the seedling from growing properly. Fine charcoal (not ash) is good addition too but soak with compost tea or urine a week before using - combine with the rest before sifting with an old strainer.