Seedling Fertilizer

I thought I had the PERFECT indoor seedling fertilizer. I was using second-hand coffee grounds, adding milk to balance the pH, and diluting with water. I decided to test the nutrient content with my little chemistry set and was sorely disappointed. I know there are a lot of ideas for seedling fertilizer, but anyone have any that are home bi-products, tried-and-true, and not fly breeding haven? Also, consider we are talking greens which I will be ingesting with minor cleaning. Thanks!!

I have a big jar for watering my seedlings, every once in a while I put a handful of fresh wormcasting in the jar, which gets mixed with the water (rainwater, not tap). When I water the seedlings I never empty the jar completely, so there are always some wormcastings left at the bottom.

It's fun, when the water settles you can see all the squiggly-wigglys swimming around. It seems to be doing good to the seedlings.