My front lawn only has one thin layer of good top soil (around 1").
Below that is sandy soil. My front lawn always has much more bare
spots than the lawn in my side-yard (3" top soil) and in my backyard
(6" top soil). I believe the fact that my front lawn has thin layer of
top layer is one of the primary causes of having bare spots in my
front lawn (the other cause is I don't water enough for this sandy
soil). My theory of my problem is: The sandy soil doesn't hold water
well, and the water in the thin layer of top soil gets dried up too
fast -- the grass suffer.

What can I do about this without completely replacing the soil? Of
course, I can keep watering the lawn very frequently to keep the sandy
soil moist; but this is expensive to do that. Therefore, I am thinking
of improving the soil.

I am under the impression that I can improve the soil by putting a lot
of organic materials onto the soil, and let earthworms to incorporate
the organic materials into the soil. I have a couple questions on
doing this:

- What is the best way to improve the soil? Is using compost the
best way? Or should I use organic fertilizer such as the one made from
sewage (from Milwaukee or some other city)? Any other choices that I
should check? Is there something that is cheaper and better?

- Can I mix using organic fertilizer and chemical fertilizer? Do I
have to go totally organic? Will the chemical fertilizer hurts
earthworms in anyway?

- Should I expect to see thicker top soil in three years if I use
organic fertilizer twice a year and spread a lot of compost on my lawn
every fall?

- Is there any existing "action plan" that I can refer to?

Thanks in advance for any info on this issue.

Jay Chan