I saw that you need to make an appointment. Is that just during the tulip festival or because of Covid or is that always the case?

It's because of covid.

You can chance showing up but may have to wait if they have reached capacity for that time slot. The tulip festival is the busiest time of year.

I've only been there once, just this past weekend. It's my understanding the reservation times are to help socially distance from others during the same time.

The appointments are part of the COVID precautions.