What are the little grey eggs on top of the soil/moss on the plants?

I water the office plants every Friday. Today, I noticed what looks like little light gray pebbles on the moss covering the dirt in the pots. They are on all plants in various offices. They feel hard but have a mushy center when cut open. I've also noticed that the roots are pulling out easy. I thought I might be over watering. Am I in for a huge bug infestation?