13 inches too close?

[AlittleSalt]

I'm planning our pepper beds to plant out. They fit perfectly if I can plant them 13 inches apart. (I have always planted 18" apart)

So, I Googled it,

"Plant peppers in a bed that receives full sun. Provide a sandy loam soil that drains well and contains plenty of organic matter. Depending on the size of the pepper varieties planted, spacing should be 12-18 inches apart."

What do you think - too close together?

Here are the varieties. The number is how many plants I have of each kind:

6 Thai Chili
6 Red Cherry
6 Jumbo Jalapeño
6 Jimmy Nordello
4 Early Jalapeño
2 Cayenne
2 Chocolate Beauty
5 Tabasco
5 Shizhito
3 Aji Amarillo
5 Leutchauer Paprika
3 Anaheim
2 Thai Chili Large
5 Serrano
6 Poblano
5 Stavros Pepperoncini
3 Penot Noir
3 Chocolate Cherry Bomb
2 Hungarian Wax
1 Twilight
1 Riot
2 Sweet Cayenne
3 Bishop’s Crown
2 Peppadew
6 Aji Limon

This is how it looks laying it out. Oh, and anything you see green in that bed is a volunteer tomato plant. There's a bunch of them.