What can I do to fix this? Is there something I can add or take out.

Before I know it it'll be time to transplant the rest of my vegetables.

Sounds like a good case of severe nutrient and mineral deficiency because your bed is essentially sterile.

Compost is only a source of nutrients IF there is an active soil micro herd in the bed to digest it and convert them. In a new bed that doesn't exist. And in a new bed with no incorporated soil it can't even begin to develop.

Compost is primarily a soil amendment, not a growing medium. It can be a source of supplemental nutrients with time to decompose over time but only dirt contains the needed minerals and micronutrients unless you provide them regularly.

So you need to mix in soil - dirt. Minimum of 1:1 soil to compost. And until the soil food web - the bacteria and soil residents - has time to develop over at least a couple of seasons you'll need to supplement with nutrients and micronutrients - fertilizers. The type you use is your choice but liquids are more fast acting than granular supplements.

Dave

I have noticed that fresh MC does tend to kill or stunt plants....after it's weathered a year, it's great stuff.

They never bother to explain that compost has to be converted to nutrients usable by the plants and that conversion requires active, diverse soil bacteria and by soil-dwelling residents - worms, beneficial nematodes, grubs, pill bugs, etc.

They eat and digest the compost and poop out nutrients the plants can use and absorb with water. They are all lumped together under the label "soil food web". Unless you directly add them (which many do) and add dirt to the compost (which already contains them), it takes seasons of time for them to move into the beds.

Add to that the issues others have mentioned with mushroom compost (as opposed to manured compost) of low nutrient levels, high salts, and alkaline pH. All of those issues also require time to resolve themselves. The soil food web needs time to grow, the salts need time and rain to leach out, the compost needs time to decompose and neutralize the pH down to neutral, and the low nutrient levels need to be supplemented with additional sources.

You don't have to wait numerous seasons to use the beds. They can be used but you do have to supplement the nutrients and the soil web until the beds are well established and that takes seasons. You will also have to add fresh compost 2x a year as the beds shrink (decompose).

So mix in as much dirt as possible, research adding Mycorrhizae (bio-organics), look into nutritional supplements (both organic and synthetic), and accept very limited results this year. Over the winter the bed will be improving (any new beds need to be fall constructed) and salt leaching out so next year will be better if you keep up the supplements. By the 3rd year you'll see substantial improvement and by the 4th you'll have great beds that only need minimal side dressings with fresh compost to sustain good growth.

Hope this helps.

Dave