While mushrooms in your lawn may be unsightly, they are actually beneficial to the lawn ecosystem. The extensive root system of lawn mushrooms help the soil retain water and lawn mushrooms also help to break down organic materials, which help add nutrients to the lawn.
To keep them from spreading, however, you will want to remove them as soon as you see them as the spread quickly. During removal, you will want to contain the top, remove it, and immediately place them in a container or baggie to keep the spores from spreading. The stem of the mushroom will wither and die without creating new ones.
The below cultural practices will also help keep them from coming back:
Mow high. Not only will your grass appreciate this, the mushrooms will suffer. Check out our mowing guide here. Also, remove all mushroom tops prior to mowing your lawn to reduce the spore spread.
Dethatch your lawn. While thatch is generally good for the lawn by providing organic matter, your lawn doesn't need this right now.
Bag your lawn clippings when you mow. Again, your lawn does not need this organic matter at this time.
If you have excessive shade, pruning some tree branches will help. Your lawn will also be happy with the extra sun.
Water your lawn appropriately. During different times of the year, your lawn will require different amounts of water. Check out our watering guide here.
If these practices don't help, a fungicide may be required.