The most likely culprits are tiny baby slugs or earwigs. Both love the tender petals. To catch them set a wad of damp newspaper near the plant. In the afternoon both slugs and earwigs will hide in the cool paper. There is a slug bait that also takes care of earwigs called Sluggo Plus. You can also go out at night with a flashlight and catch them in the act. Handpick and squish them. Keep growing, Marianne Binetti