Adrienne
I’ve done likewise to you this autumn and used spent haulms of healthy tomato/potato plants, allied to the spent compost to create a ‘bed’ which I covered with grass cuttings and then topsoil (which created a ditch around the bed).
I sowed winter onions and garlic in it and all are now showing healthy shoots under 2 weeks later.
Too early to say how super-duper it might be or not, but it certainly won’t kill your crops!!