Soybean, also known as edamame, earns its spot on the challenging list because of how much critters love it. Grow a crop of edamame, and you’re rolling out the welcome mat for deer, groundhogs and rabbits. These animals consider soybeans candy. Take care to protect plants as soon as you plant, which shouldn’t be too early, because soybean is very cold sensitive. Wait until temps are reliably above 55 F.