He picked 80 peppers because 7 + 12 + 14 + 12 + 5 + 18 + 12 = <<7+12+14+12+5+18+12=80>>80
80% of the peppers are not hot because 100 - 20 = <<100-20=80>>80
He picked 64 non-hot peppers because 80 x .8 = <<80*.8=64>>64
#### 64