If you have mushrooms growing in your garden, this is actually a good sign. When you have mushrooms growing in your lawn or garden, this means that the soil is rich and fertile. Mushrooms can be a nuisance in a garden, however, and they are nearly impossible to get rid of completely. You can take certain measures to control the mushroom population in your garden, or you could simply turn the mushrooms into the garden soil with a pitchfork to further enrich and fertilize your soil.
Dig up the mushrooms from your garden using a spade or shovel. Remove all of the mushrooms and discard them or toss them in your compost heap if it's far away from your garden.
Spray the mushrooms with a fungicide. Follow the directions on the label exactly. The fungicide will usually kill the mushrooms but won't necessarily prevent spores from producing new mushrooms, so you may need to use several applications of the fungicide.
Lay landscaping fabric or black plastic around your garden plants. Cut the plastic or landscaping fabric so that you don't cover any small shoots of garden plants or seeds.