I ordered a smorgasbord of seeds of horse-friendly herbs and flowers that I'd love to plant in my pasture to create a medicinal, free-choice grazing area. However, most of these seed packets say to start them indoors several weeks before the last frost. I'm wondering what most people use to start a mass amount of seeds? I've purchased seed trays in the past but that can get expensive. Anyone have any ideas or experiences they mind sharing? I saw a YouTube video from one gardener who used egg cartons to create their own seed trays. I have plenty of egg cartons....so that is an idea, but I'd rather have feedback from others who have tried it first.