Certified GKH Gardening Expert
They are mushrooms! This is due to the soil remaining wet for too long. This is likely because of the materials covering the soil. This paper should be tilled in, or removed prior to planting.
This soil should be allowed to dry out throughly. Although those mushrooms are not harm to your plants, they are a sign that there is a good bit of rotting material in the soil
This will be what is, also, causing bloom drop.
I would recommend removing the covering material from the soil and treating with dolomitic lime and wettable sulfur. This will kill off anything bad in the soil, as well as condition the pH and contribute calcium and magnesium.