bitter greens

My lettuces looks so good and tastes so bitter.  This was the first year I have grown lettuces.  I started it in the fall, tried four different kinds of leaf lettuces.  I thought we would be enjoying lettuces out of the garden until it got hot.  No one wants to eat it.  Did I grow the wrong kind?  I thought maybe it needed more water, so I have been watering it, that has made it grow more, but it is still just as bitter.  It's in a first year hugelbeet with lots of organic material.  The bed has a different variety of leaf lettuces on each corner and bush peas through out.  Would love any ideas.  Thanks

It likely needed more water earlier during growth. Or, it is too hot. When it gets warm and your growing lettuce, baby leaves are the best. No big deal, just try again.