Making Your Own Garden Soil Mix

I have put in a raised garden. I gathered cow manure in December, added food scraps to it, and let it cook for about 5 months. Before I put the soil in the boxes I mixed it with 1/3 vermerculite, 1/3 potting soil and 1/3 aged manure. Now my plants have turned yellow and are not growing What have I done wrong? What do I do to get a nice green garden?

Hardiness Zone: 6a

By Sue from OH