Will the salad still be good or do I have to start over and make it again?
Well, it all depends on how much the mushy-ness bothers you (and how mushy they are), what recipe you're using and how important the wheatberry element is. Can you tell us what recipe you're using?
I don't think that the broth would make them mushy, unless perhaps somehow it's because of the salt content of the broth. Purely brainstorming though.
I agree with the above and I'm thinking you used too much broth.
I've found that recipes tend to over cook wheat berries. I do an overnight soak and a quick boil 10? minutes just to get rid of anything "bad". You can always use the mushy ones to make more of a porridge type thing. Add milk/cream bananas, etc.
wow, did you cook them for 10 hours or something? I've never cooked mushy wheat berries and i cook them a few hours, so i am surprised. the cereal or soup suggestion is a good one for using them up. the type pf water or broth should not play into causing mushiness.