trax wrote:

I have a big amount of lawn approximately 10,000 square feet. Location
Northern California. The lawn was established when I purchased the
house. It is a thin blade grass. I use the 'Scotts' fertilizer plan
and water regularly. The lawn was absolutely beautiful a few months
ago (April & May) but recently it has turned brown in spots and looks
dry and has lots of crabgrass. Please advice, what can I do to get my
beautiful lawn back. I also aerote twice a year.

Crabgrass is an annual. The only way to prevent it emerging is to apply a
preemergent crabgrass killer at the proper time in early spring, this
prevents last years crabgrass seed from germinating. You also need to water
deeply and regularly or lawn grass will suffer but weeds of many types will
not only survive but will flourish and crowd out lawn grasses. You also
need to mow regularly and to the correct height (no less than 2" and remove
no more than 1/3 the height of grass at a mowing), mowing too short will
harm lawn grass and encourage weeds, especially crabgrass. No matter how
diligent crabgrass will still emerge in spots, it's best to dig it out with
as much of its root as possible... spraying with spot killer will only
create a bald spot which is much more likely to host weeds before lawn
grass. You are obviously not following the Scotts program or you'd have
laid down preemmergent crabgrass killer with your first fertilizer
application in early spring (Scotts Halts +2). And the best thing one can
do to keep one's lawn healthy and weed free is not to walk on it... if you
permit kids to play on your lawn then you had best resign yourself to living
with crabgrass. If you don't trample your perennial shrubs why would you
trample your lawn grass and expect it to survive.