Slugs in my garden

They are eating my marigolds, have compeletly spoiled my ranunclus flowers,0 whole plant is dried now.
I just bought a snail and slug killer, its name is multiguard, this is eco friendly as it has iron chelate and not methaldehyde, and this product is gentle on soil and it dissolves into soil.
I now understood how difficult it is to grow our own food, people take their food for granted, only if they work on growing their own they would understand the efforts that go in producing the food that we eat.