Now is the time to encourage flowers for next season. If the bulbs are crowded split up the clumps. Give the bulbs a good sprinkling of potash now, it is a good idea to leave the foliage to die back naturally. I'm sure that you will soon enjoy flowers.
The reason bulbs go `blind` is because they get cut back too soon by over keen gardeners which robs the bulb of food it needs to flower next season which is stored in the leaves. Wait at least six weeks after flowering before mowing lawns with daffs growing in it and feed with a liquid feed