There are a lot of moisture and the connection to the soil is dense, it happens, because the old flowers and the leaves die become the natural compost (decayed plants fertilizer on mineral oils filled), the problem is the flower beds, we fail to Rake them off in the autumn, and compost in the soil, and turns to the yearand it gets trapped in a dense, much of the moisture and little if any of the air carrier concerned, and decayed becomes the new top of the soil, and yes it tacky.