Basic modes for folkies is much easier than that. The ones you need most are -
on the white notes of a piano, from C to c = Ionian
from G to g = Mixolydian
from D to d = Dorian
from A to a = Aolian
Most British/American/Aussie/Kiwi 'folk songs' use those ones, except for areas where there is an Asian or European influence.
The first 2 are most common for songs but if you're playing at a diddly session you'll probably need the other two as well.
Robyn