I'm in Illinois and my lawn has so many weeds in it and I've tried for the last two years to get rid of to no avail. I've tried everything from pulling them by hand to using spraying them individually with a general weed killer to using Scott's Weed and Feed with a handheld spreader and nothing seems to help.

What is it I'm doing wrong? Should I have used the Scott's Weed and Feed with a push spreader instead or should I just try a totally different product? It seems like lawn care services use some sort of a spray. I just want to know what their secret is.

Like I said, I can't afford to hire someone to fix this lawn, so I would like to have some suggestions on what to do and use on my own. Also, I would like to add some grass seed to some sparse spots - should I do that before or after getting the weed problem under control?

Thanks in advance for any suggestions!

1. Soil test. You can't have a great lawn with poor soil. It will save you money in the long run as it will eliminate unnecessary fertilizers/amendments. Logan labs, $20 basic soil test, www.loganlabs.com.
2. Kill weeds with a liquid weed killer(s). Weed and feed products are an ineffective means to kill weeds, and it provides fertilizer at the wrong time. Spray weeds with a product like Weed B Gone Max via a hose end sprayer or tank sprayer. Some weeds require Weed B Gone Clover, Chickweed and Oxalis killer, and some require two doses two weeks apart.
3. Apply a preemergent herbicide like Dimension, Stonewall, or Barricade now to kill all future germinating weed seeds, especially crabgrass which germinates when soil temps get above 60 degrees. This will also prevent new grass seed from developing, which is fine since you should seed in late summer/early fall. The preemergent should have worn off by then, but read to label to make sure it wears off about a month before you do any seeding.
4. Raise your soil's level of organic matter via regular applications of organic fertilizers like Milorganite, corn and soybean meal, compost, and mulch mowing. Your soil test will indicate the percentage of organic matter when you get it back.
5. Mow your lawn regularly at the correct height. Most cool season grasses do well around 3 inches. Some prefer a bit longer, some a bit shorter. When mowing don't cut more than one third of the blade at a time. So if you want to keep your lawn at 3 inches, then mow it when it's 4-4.25 inches tall. If you like 2.5, then mow it when it's about 3.25 inches tall. Taller grass needs less water, and keeps the ground a bit cooler, but too tall can lead to problems.
6. Water your grass when it needs it, and do it all in one shot. Short daily waterings encourage shallow rooting. Most grasses need about one inch of water per week but this can vary. Some areas might need more, some less depending on proximity to the street, shade, soil, etc. Do your watering in morning before sunrise to reduce evaporation and disease.
7. If you do use synthetic fertilizers do so at the correct time and the correct rate. For most cool season grasses this is in mid to late spring (May), early September, Late October, and late November (this one should be quick release nitrogen applied when the grass has stopped growing but the ground isn't frozen). If you use all organic fertilizer you can pretty much apply it whenever. Never apply synthetic fertilizers in the summer. Organics can be applied in the summer, but I would cut down on the rate and frequency a bit.
8. Assess your lawn in late July/early August to determine if you want to over seed, or renovate (kill all grass and start new lawn). If you don't need to seed then apply preemergent again in late August to kill winter annual weeds.

Fescue lawns tend to thin out for various reasons. Once they thin out the only way to make them dense again is to add more seed. Many people will mix fescue with Kentucky bluegrass so the bluegrass will spread and fill in when the fescue thins out. Thin lawns allow the weeds in to take root.

Since you have a weed problem now, I would raise the mower all the way to the top until you notice the weeds are declining. Tall grass shades the soil cutting down on the weed seed germination.