ahh yes the joys of new homeownsership, am there as well and just dealt with 1/2 acre of crabgrass

i got alot of flask for doing it this way but it worked for me.

1) stop watering, (period, no water till the new lawn is in)\
crabgrass is an annual, so the seeds are down there, and will germinate shortly (few months) the current batch should be dying off within the next 6 months
2) rip out as much from above ground as you can, as fast as you can.
kill the green stuff, let the sun dry it out as much as possible, and turn it into mulch)

3) till deeply (this is where i got the most flack) by tilling you will bring up the seeds that will turn into crabgrass. but by deeply i mean at least 6 inches down, and till it through and through, not a single clump should remain intact
4) get/steal/buy lots of compost, newspaper, and soil (same as is currently in the ground)
5) ;lay down a single layer of newspaper (black and white only please) and mist it so that it doesnt fly away.
6) lay down at least 4" of compost and natural soil (not the potting or fake soil) on top of the tilled lawn
7) spread new seeds for your lawn cover)
8) spead a light layer of soil and compost on top of the seeds
9) water well to about 6"
10) keep misted daily and water every 3-4 days
11) in about 2 weeks you will see nice little green things pop up

my 1/2 acre of crabgrass os now a mix of clover and other grases, about 15 crabs came up where i didnt lay down the newspaper properly. the newspaper will dissintegrate in about 3-4 weeks, and hopefully by that time the new grass will be growing and will prevent the crabgrass from coming back.

for the next three years you will need to yand crabgrass as soon as you see it.

woohoo

I'm going to try riegersteve suggestion. Also I've been using corn gluten spring/ mid-summer/ fall this is an organic method but very long to see outcome. The corn gluten will prevent the crab grass seed ( any seed) from growing. Also cut your lawn 2.5-3 inches high this will also prevent weeds from growing,.So these methods may be an answer for both of us.
Also as a new gardner, if you don't have a compost bin...get one. Contact your local city or Agricultural extention Dept. Follow the instructions and it will make clean up and gardening easier.
Good Luck

I'm just going to suggest something completely different.

Can we assume you live in Sacramento, CA? Because crabgrass is a summer annual plant that requires full sun to thrive. If you have something growing in the middle of your lawn currently, it is not crabgrass. Crabgrass is dead, Dead, DEAD in the winter and does not come back in the spring...except from new seed. Can you take a picture and post it? We can help you post it if you can take the picture.

What I suspect is you have some sort of fescue growing around the edges and St Augustine grass growing in the middle. St Aug will likely be green now if you have had a mild but rainy winter. St Aug is a broadleafed, warm season, grass that resembles crab grass to the uninitiated. If I recall Sacramento, CA is a fine place to grow St Augustine due to the warm summers and mild winters.

First you have to decide what you want to use the lawn for and what you want it to look like. If you are going to play football on it and let the Great Dane pups frolic, then you need different grass than if you are going to just look at it. You also have to decide fine blades (like the fescue) or coarse (like crabgrass and St Aug)? Fescue is going to need a lot of water in the summer because of your heat, but there are varieties that will work well. St Aug can be very lush, but you have to adjust to the coarse appearance.

Next you should know that you don't have to have crabgrass at all. There are a couple things you can do to keep it away from your yard. First is to water only infrequently but deeply. Crabgrass seed needs several days of moisture to germinate. If you water once and let that soak in for a week or longer, the crabgrass seeds will not germinate. However Mother Nature is about to through you a curve and water for several days. When that happens your second line of defense is to have the tallest grass you and your spouse can agree to. Set your mower to the highest setting and mow at that height for a month to see how you like it. Don't judge before the end of a month because it will look straggly until it all grows up to the right height. So why mow high? Because crabgrass requires full sun to thrive. Tall, dense grass provides enough shade on crabgrass seedlings that they cannot set a good root, so they die. In this regard, St Augustine is a winner for a few other reasons. One is that St Aug is a sod-forming grass that grows very densly in full sun. Fescue is a bunch grass that grows one plant from each seed and does not knit together to cover the bare ground. Bare ground will fill up with weeds. That is Mother Nature's law. The other advantage with St Aug versus crabgrass is that crabgrass is not very salt tolerant while St Augustine will grow out into the sea if you let it. Thus you can kill any amount of crabgrass and retain all the St Augustine by sprinkling the dampened crabgrass with baking soda. The crab dies in a day or two and any intermingled St Aug is unaffected.

Sac'to has a lot of options for either warm season grasses or cool grasses. You need to make some decisions about what the lawn will be used for, how you want it to look, what you are willing to put into it, and what you are willing to put on it. Then get back here with the answers and we can help you.

By the way, tilling is a bad idea for lawn surfaces. It might work for gardens, but you don't have to walk on those. Tilling now will result in a lumpy, bumpy lawn in 3 years.

Thanks for all the suggestions. I will try to get a picture taken this weekend. But I know for sure it is crabgrass, as they all died over the winter and are now popping back up. Is there another way to fix the lawn without having to till it? It is the front yard, we don't have any traffic there and it's about 700 sq feet, very small.

Sounds more like crabgrass if it died out. Still late January is a little early for most crabgrass to sprout. Now that its been a week, is it still looking like crabgrass? Is the rest of your lawn dormant?