A turf lawn that sprouts a colony of early spring daffodils is a most delightful sight, and it is rather easy to achieve simply by planting bulbs randomly around the lawn. But you will need to limit your use of pre-emergent weed killers, which can kill off the daffodils before they even appear. And if you use post-emergent weed killers, they will need to be carefully applied, spot-spraying individual weeds rather than broadcast spraying. Further, because daffodil foliage needs to die back naturally in order to replenish the bulbs, you will need to allow your lawn grass to grow long for the spring period. When the daffodil foliage turns yellow and dies, then you can resume normal mowing.