Every year I have the same problem: As soon as newly planted seeds begin to sprout or newly transplanted things like cabbage or broccoli are put in, they get eaten! Have never known what the pest is, but last year discovered that if I put window screens down over the rows and the individual plants, they are safe!
This year thought I would do an experiment at least to determine how big the pest is. So, I have 3 different sizes of screening over the plants this year, quarter inch hardware cloth, half inch hardware cloth, and finally 1 inch chicken wire. Only have about 3 plants out there for now, just to see what happens. No window screen out right now, since I know that works. This is to determine how big the openings in the screen can be and still work.
I thought the pest was grasshoppers but there are none out yet, and already I have lost a plant. The whole space is fenced to a height of 7 feet with half inch hardware cloth already. I'll see what happens. Hope I get this figured out.