Your caterer will probably prepare a certain number of vegetarian meals based on his experience of the percentage of guests who usually ask for one. If you know that there will be X-number of vegetarian guests at your wedding you can share that information so he’s aware of a minimum number of vegetarian meals to offer.
Vegan, gluten-free, kosher and other special meals should be ordered in advance since your caterer may not include them in his usually tally. Some of these meals may cost an additional fee.
Be sure to tell your caterer how many of each special meals there are, and if you can which table each guest will be at so the waiter brings the right meal to the right table.
You may not be aware of every guests’ dietary restrictions, including allergies, but your guests do. They’ll know to ask if something is made with nuts or has mushrooms in it and will take care of themselves. You don’t have to prepare for every possible situation.
I also suggest talking to your caterer about what they can do for guests with dietary restrictions and if they should prepare a few dishes on the side just in case or if you need an exact number to order in advance.