One tree can make 300 pounds of fruit.
In some cases, the ideal thing with organic gardening is to have more than one garden - one plot where you're adding compost and letting it rot and another where you're actually planting something. When you add too much compost into the garden and plant the same year, it might be difficult for the plants to grow the first year, as the compost decomposes.
Fleas actually like warm weather. I don't know that in the summer we'll see a reduction.