Absolutely kill the plants and DO NOT TILL. Yes, I was shouting. When you kill the plants you leave the soil structure intact both physically and biologically. If you could scrape off the surface plants, that would work fine, but that's hard to do on a small scale. If you're doing more than 10,000 square feet you might want to hire a landscaper with a tractor and box blade to scrape it off. They can do that very quickly and you'd be ready for sod or seed right away.

This is not the best time of year to put seed down but it is fine for sod. Spring seeding always brings up the crabgrass along with regular grass. Fall is the best time for northern type grasses.

Darn. I guess I will be waiting to seed in late summer/early fall then. I was hoping to have it all done in time to have a nice lawn for summer, but I suppose it will be better to do it the right way. :-)

Thanks dchall, & becky for the great advice.

To add to the advice you've already been given, now would be a great time to have a soil test done so you can begin to get the soil ready for the new seed. If there are problems these issues can be addressed now. Another advantage (I know this will sound silly) is that the current grass/weeds will be healthy when it comes time to kill them. Healthy plants are much easier to kill with herbicides than unhealthy stuff because they absorb the weed killer much better.

Use the spring and summer to learn and practice good grass management habits. Sometimes well cared for weeds will look very nice for a season.

Basics of Lawn Care

After reading numerous books and magazines on lawn care, caring for lawns at seven houses in my life, and reading numerous forums where real people write in to discuss their successes and failures, I have decided to side with the real people and dispense with the book and magazine authors. I don't know what star their planet rotates around but it's not mine. One of their problems is they write for local readers. With that in mind, here is the collected wisdom of the Internet savvy homeowners and lawn care professionals summarized in a few words. This should work for most of the US of A. If you follow the advice here you will have conquered at least 50% of all lawn problems. Once you have these three elements mastered, then you can worry about weeds (if you have any), dog spots, and striping your lawn. But if you are not doing these three things, they will be the first three things suggested for you to correct.


Watering
Water deeply and infrequently. Deeply means at least an inch in every zone, all at once. Infrequently means monthly during the cool months and no more than weekly during the hottest part of summer. Do not spread this out and water for 10 minutes every day. If your grass looks dry before the month/week is up, water longer next time. If that does not work, then you might have to water more than once per week during the summer's hottest period. Deep watering grows deep, drought resistant roots. Infrequent watering allows the top layer of soil to dry completely which kills off many shallow rooted weeds.

You will have to learn to judge when to water your own lawn. If you live in El Paso your watering will be different than if you live in Vermont. Adjust your watering to your type of grass, temperature, humidity, wind, and soil type. It is worth noting that this technique is used successfully by professionals in Phoenix, so...just sayin.' The other factors make a difference. If you normally water 1 inch per week and you get 1/2 inch of rain, then adjust and water only 1/2 inch that week.

Mowing
Every week mulch mow at the highest setting on your mower. Most grasses are the most dense when mowed tall. However, bermuda, centipede, and bent grasses will become the most dense when they are mowed at the lowest setting on your mower. In fact there are special mowers that can mow these grasses down to 1/16 inch. Dense grass shades out weeds, keeps the soil cooler, and uses less water than thin grass. Tall grass can feed the deep roots you developed in #1 above. Tall grass does not grow faster than short grass nor does it look shaggy sooner. Once all your grass is at the same height, tall grass just looks plush.

Fertilizing
Fertilize regularly. I fertilize 5 times per year using organic fertilizer. Which fertilizer you use is much less important than numbers 1 and 2 above. Follow the directions on the bag and do not overdo it. Too much is better than too little*.

At this point you do not have to worry about weed and feed products - remember at this point you are just trying to grow grass, not perfect it. Besides once you are doing these three things correctly, your weed problems should go away without herbicide.

* This used to read, "Too little is better than too much." Recent test results show that you cannot get too much organic fertilizer unless you bury the grass in it.</i>

I am appending to this thread because I have a similar till vs. kill question and wanted to know the right order and timing to kill weeds and apply amendments to be ready for a late summer/early fall seed application to establish a cool season grass lawn in shade/part shade in Zone 7A (northern Virginia).

My existing lawn is at least 90% weeds (at least they are green for summer) but I want to work to establish a lawn in late summer/early fall. I appreciate the advice from beckyinrichmond about when to apply weed killer to those existing weeds.

The advice that came back from my soil test did not mention weed eradication at all but indicated I should till in the amendments, 110 lbs of limestone per 1000 sq. ft. and the nitrogen only fertilizer (soil is high or very high in other nutrients), to a depth of 6 inches. My local extension agent indicated that if I can't or don't want to till then I should aerate to provide conduits for nutrients to reach root zone. First question: What are thoughts on tilling vs. aerating vs. surface application of these amendments?

My bigger question is on the order of events. Should I apply both amendments now (using suggested method from above), though I may spread out the lime applications over the next six months, and start killing the weeds in July, and apply another dose of lime just before seeding in late August (hopefully). Or is there a better order of events? I read on another thread that I want the weeds to be healthy before I kill them (they will uptake the agent better) so I am thinking lime and fertilizer now would be good so they will be very healthy by July.

This is a relatively small lawn (less than 2000 sq. ft.) and I am hoping to do this myself starting as soon as possible. I bought the seed mix now because I thought I might test what is now a nearly bare patch that receives the least amount of sunlight. But I am trying to be patient. Thanks for all your advice.

Don't till. Aeration would be helpful to get the lime down into the soil but it's not required. If you're going to aerate, it would be good to do it anytime from now to early August and put half the lime down right after you aerate. Water it in. That would give the lime time to settle in and allow time for the holes to fill back in before you seed (you don't want the seed to fall too deep down the holes). If you don't aerate, you can put half the lime down now. Put the other half of the lime down in late fall. It's better not to do lime and seed at the same time, as the lime temporarily pushes the surface pH up high. You may want to look into fast acting lime instead of ordinary lime. You would use a lot less at a time of a product that costs more. It does work faster. Ordinary lime can take months and even years to work. See what they have wherever you shop for supplies. My daughter is in the Westover area and I know you have limited options locally. But it is surprising how much you can find at Ayers.

I think you can skip fertilizing the weeds in the summer. If they're green and growing, they will absorb the herbicide. If they're not growing, it will be because the heat is too much, even for them, and fertilizer would be another stressor. I suppose you could do fertilizer for them now. From my experience, crabgrass and Bermuda are thriving in August no matter what. Everything else is limping along.

You could do the first round of gylphosate in early August, do light watering to encourage weeds, then do another round in a couple of weeks, more light watering, then spot spray any remaining stragglers right before you seed. Mow everything as low as your mower will go and bag the clippings. If there are still mats of dead vegetation on the ground, you need to rake them up so seed will fall on bare ground and not on dead leaves. Aim to seed in late August. If it's still 100 degrees, wait a bit. Hopefully it will be more like 85. Water the ground well. Spread your seed and fertilizer. You can lightly rake some dirt over them or use peat moss or compost for a very, very light covering. You don't have to cover, though it is helpful. You do have to water. Water lightly several times a day so that the seed stays moistened. As the seedlings come up, you can decrease the frequency and increase the amount of water.

What kind of seed do you have? Do you have irrigation? If not, you need to gather hoses and sprinklers and a timer and see how you can set them up to cover the area. I did overseeding for my daughter's yard a couple of years ago and there was just one outside spigot. I got a timer that connected to two hoses. One hose went to an oscillating sprinkler in the front yard and one hose went to the back where there were two rotors set up with a connecting hose, daisy chain fashion. The further rotor got less water and it wasn't the best set up but it was okay. The timer sent water to one hose then to the other at set times for a set number of minutes. The yards were small, maybe 1500 sq ft all together.

I bought Pennington Smart Seed blend with fertilizer. It includes a few fescues, bluegrass and ryegrass. So I wasn't sure if /when to apply additional fertilizer. I could return this if you recommend something else. I do need to invest in additional hoses sprinklers and timers. I have one spigot with a split connection so one hose will be directed to the back possibly with a configuration similar to your daisy chain for side yard and another for the front. I estimate area to cover is no more than 1500 sq ft. I'll look at HD and Lowes for lime options. I'd found pulverized and pelleted cheap at Tractor Supply but may not be fast acting.

Pennington Smart Seed is a good choice. However the Pennington Smart Seed Tall Fescue might do better if you have shade. KBG needs lots of sun. Rye isn't going to survive in our heat. If your yard is mostly sunny, the mix with the KBG could work. Are you sure it has fertilizer? What I've seen is just seed. Are you interested in synthetic or organic fertilizer?

I rechecked the bag. It's called Smart Blend. It's their seed mix plus fertilizer (available at Costco). I do prefer organic but open to whatever will be most successful. I'll look for the tall fescue at other locations if you think it might be more successful in my shade. I've got one sunny area but the front and most of the back are pretty shaded by tall trees.

Thank you so much for all your help.