Thank you.
Lavender always works to have butterflies if you won't mind having much of the cabbage butterflies, I noticed you have cabbages, they'd probably lay their eggs on them. I suggest you collect their larvae and place them in a glass with a cover, that way you can do some damage control on your cabbages and have plenty of butterflies to start with. By the time they would hatch and lay eggs again you must have already harvested your cabbages and if not just continue doing the process. Good luck!