I've seen that the museum is free after 3pm. Would that include the butterfly garden? If not are we allowed to just purchase a ticket for the butterfly garden?

On saturdays , they seem to be closing the butterfly garden. You may want to check the weekend hours.

L.A. County residents receive free Museum Admission 3-5 pm daily. Additional tickets must be purchased to see special exhibitions, Butterfly and Spider Pavilion, 3D Theater, and other special ticketed experiences.

As all mentioned purchase butterfly garden tickets online, note they go quickly on the weekends

You can buy a last minute ticket for the butterfly garden but they sell fast and they are time specific. It's better to buy them in advance. I don't know about the free admission after 3pm. I do know that 2 adults and 4 kids can get in free with EBT.

No, the butterfly garden is a separate ticket, reserved for a specific time slot, so it should be purchased ahead of time.

Yes, you can purchase only the ticket for the butterfly garden