Something has been munching my seedlings and transplants off right at the ground, so I’ve been using cardboard toilet paper tubes to foil the little buggers. When planting large seeds like melons or squash, I push a section of tube (I cut the rolls in half) into the soil so about 1/2″ of the tube is above ground level and then plant my seed inside the tube. I do the same with small transplants, making sure not to damage the roots as I push the tube around the plant. The tube will decompose over the growing season.
It does work. I planted out three small pepper plants the other day, but only used a cardboard ring around two of the plants. The third, unprotected pepper was gone by the next morning.
To use this method with bigger transplants, just cut the ring open and slip it over the plant’s stem.