Yes, you've read too many forums. If you put down pre-emergent in March it's going to be a while before you can seed. Do you need to seed? What kind of grass is it? Where do you live? Are you saying you have 50% crabgrass because of what you had last year or are you saying you now have 50% crabgrass? Crabgrass is an annual and the pre-emergent in March should be preventing it from germinating. So maybe you have some other kind of weed? Weed B Gon and weed and feed does not kill crabgrass, by the way. They kill broadleaf weeds, not grassy weeds.

Thanks Becky. I would like to seed as there are a lot of bare batches, and I'd prefer to fill them with grass rather than let more weeds move it. Brand new lawn, seeded by the builder so I don't know what they planted. The 50% crabgrass 50% comment refers to what the yard is now. It's definitely crab grass, I just was too late applying the pre-emergent. Weed B Gon has a crabgrass specific product, maybe it's new? Or maybe it's nonsense ha. Thanks!

Where do you live? When was the yard seeded? March should have been early enough for pre-emergent. What did you use and how much product on how many square feet? Can you take pictures of your grass and crabgrass? Can you ask the builder what kind of grass he planted? The Weed B Gon crabgrass killer should work on crabgrass. Regular Weed B Gon wouldn't.

Indianapolis, IN. Seeded some time before November but I doubt I'll be able to get any specifics beyond that. I used Scotts Step 1 crabgrass preventer and feed. Used about 2.5lbs, which is what it called for for my 1000 sq foot yard,

It's dark here now but I can get some pictures tomorrow.

Seed seed seed, then start blasting the crabgrass. Once under control, all you need is a good pre emergent schedule & spot spraying

You likely have a cool season grass like Kentucky bluegrass or turf type tall fescue. Possibly rye or fine fescue. Or a mix. Those are best seeded in the early fall. Your pre-emergent will prevent germination for four months (April. May, June, Juky). So if you want to overseed, you should plan to do that in mid to late August. The Weed B Gon crabgrass killer says to apply in the spring when the crabgrass is 4 inches high and to reapply 3 weeks later. Use when day temperatures are above 45 and below 90. Limited to two applications a year. The Scott's product you used should have prevented crabgrass. Let's identify your problem grass before attacking it.

Since you're going to be taking pictures, if you can do it on a cloudy day or in the shade, we can see a lot more. Also get about 3 inches away from the grass when you take them.

That does not look like crabgrass. It is a grassy weed and maybe someone else can readily identify it. If not, you can use this resource from NC State. Here are some pictures of crabgrass. Your yard is small enough and the grass is clumpy enough that maybe you could just dig them out.

Yeah there's no crabgrass in those pictures. Crabgrass grows low to the ground and is more yellow than other grasses.

After you ID the grass there may (or may not) be a spray type solution for it. You can kill it out with something like Grass b Gon but you really have to be careful of overspray killing the adjacent grass. You can make a shield out of cardboard to cover the lawn grass and leave only the weed poking out. Then spray it.

You used pre-emergent in March and cannot seed for four months after that. The time to seed, if seeding is needed, is mid to late August. In general avoid weed and feed products. Instead use a herbicide targeted to the particular weeds only when necessary and use a fertilizer at the times you should fertilize. For cool season grass, that's late May, late August or early September, late September or early October, then a fast release nitrogen after the grass has stopped growing but before the ground freezes. Most fertilizer goes on in the fall. Always water after applying a synthetic fertilizer. My guess on your weed is orchardgrass. Check out the description and pictures on the turf ID site from NC State and see if it matches your plants. While you're at the site, you can see if you can identify your good grass. If it's Kentucky bluegrass, it will spread to fill in bare areas. If it's fescue or rye, you will need to overseed to fill bare areas.