Question
Are fish emulsion and liquid seaweed good enough for my vegetable garden? the soil has a good base of organic matter and I have been using cow manure up til last year.
(ithink i asked this before, but don't have the answer.)

Answer
Those are excellent choices for your vegetable garden.  Also consider mixing the two and applying to your plants in a foliar fashion every two weeks.  That also helps them tremendously.  
As far as cow manure goes, I was unclear on your statement.  Were you meaning compost from cow manure?  You should never apply any kind of animal waste in an uncomposted form to any part of your garden.  Adding compost in the spring in fall to your garden plus the fish emulsion and seaweed should give you great results!