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To kill or not to kill lawn?

Discussion in 'Turf Renovation' started by oldlawn, Mar 30, 2008.

  1. oldlawn

    oldlawn LawnSite Member
    Posts: 4

    I have an old lawn that was neglected for years (very compacted). It has a myriad of undesireable weeds, grasses, clover, etc. I want to aerate and seed, but am unsure of whether I should roundup everything first. My experience has shown that if I spray broadleaf killer throughout the summer the grass will take off enough to look good until the August heat wave comes.

    My plan was to:

    1. Mow it low
    2. Aerate
    3. Lay down seed
    4. Add some starter fertilizer
    5. Add compost and lightly rake

    Not sure if and when I should add pre-emergent to treat some of the existing weeds, grasses.

    Thanks for any input.
  2. Mark Bogart

    Mark Bogart LawnSite Member
    Posts: 174

    If you add compost, it will be more beneficial for the soil and the turf if it is worked in the first 4-6" of soil. What your asking has a lot to do with how much money do you want to invest in your lawn? If money isn't a consideration I would spray the entire lawn with a non-selective herbicide to kill all existing vegetation. This may take several spray applications. Than work in several inches of compost into the soil. Regrade your lawn, add starter fertilizer, sod, and water. Hope this is helpful and good luck.
  3. Runner

    Runner LawnSite Fanatic
    Posts: 13,496

    Yep. Just like Mark said. I don't think it will take several applications of Roundup, but a safe thing to do is wait about two weeks and then you an respray any areas that didn't get fully treated. (this wait is not a necessary thing with Roundup or anything, it is just for the benefit of eventually seeing that you got everything). If you are going to aerate it and overseed, you want to aerate the heck out of it...almost like tilling. An even better route would be to slitseed it. This assures a uniform growth pattern, and a higher yield on your seed. After that, is just watering properly. Do NOT put any pre-emergent on it of any sort.
  4. lawnpro724

    lawnpro724 LawnSite Silver Member
    Posts: 2,201

    If you have more weeds than grass, kill the entire yard off and ad compost and mix with good topsoil and till the entire yard to mix it in good then re-grade the entire lawn, seed and roll the lawn for good seed to soil contact.
  5. TonyG

    TonyG LawnSite Member
    Posts: 80

    after you set the seedbed, what do you use for a top dressing to completely cover the seed?
    We use peat and then straw, I'm looking for other ideas and a means to apply it.

  6. oldlawn

    oldlawn LawnSite Member
    Posts: 4

    Cost is somewhat of an consideration, but time is biggest. Laying sod is not really an option right now. My neighbors laid sod 2 summers ago, and their yard looks decent, but I think I could get mine looking similar with half the labor.

    It sounds like aerating it heavily, spreading seed, and raking over compost is my best bet.

    3 questions:

    1. Am I safe doing this on March 30 in VA? Some posts suggest only doing this in the fall.

    2. What precautions do I need to take when spraying broadleaf weed killer before, or after I seed?

    3. How often should I water with this overseeding technique?
  7. Marcos

    Marcos LawnSite Gold Member
    Posts: 3,720

    I don't live or work in Va, so I can't speak for the spring climate there.

    But I know the late summer "dog days" are about the same there as they are here in S. Ohio...dry....with intermittent thunderstorms if you're lucky.

    I say go for it this spring if you've got the gumption, energy, and resources to do multiple passes with a core aerator.

    I'm not sure what kind of "undesirable grasses" you have in your yard right now that you're worried about...without seeing digital pics.
    The 'spring' weeds to be mostly concerned about are the 'spreading' broadleaf type; such as white clover, chickweed, and henbit...because they'll tend to smother your work-in-progress before it's finished.

    I'm not a real big advocate of spreading a lot of compost on top of grass seed.
    Here's what I'd do; to maximize excellent seed-to-soil contact (which is an equal priority to that of getting proper watering later!)

    1) Aerate the lawn multiple times.
    Consider the experience an aerobic workout. :weightlifter:

    2) Spread over the lawn one half the intended amount of seed you intend to ultimately use.

    3) Spread compost over lawn, and as you do; take the time to rake the cores, seed, and compost together.

    4) Spread rest of seed over the top and fertilize.


    Think about this sequence...and you'll understand why and how it improves overall seed / soil contact...because it intermixes the seed better with both existing soil and the compost you're adding.

    Plus, by doing this, you're increasing the overall vertical percolation potential of the lawn (water will soak in easier down the road!:laugh:)

    Another reason I suggested this is because in the initial blog you said that your lawn is compacted.
    Well, sometimes simply aerating won't solve the nightmarish problem of "sheet wash" that could come up later in a situation like yours...when you wake up one morning, hear a clap of thunder, and look out the window only to see much of your compost sliding into the storm sewer !:cry:

    As a matter of fact...it may be a good idea to include some broadcasting of COARSE SAND (about 150# dry course sand / 1000 sq ft) right after the aeration...if it's in your "back", and your budget. ( But I don't know your soil 'type' here...so I'm just guessing)

    There is herbicide available called Drive DF, made by BASF Corp, that can really be helpful to you in this seed project.
    Here's a label:


    Drive DF is a dry flowable, so you have to mix it with water and a surfactant and spray it.
    The neat thing about Drive is that you can use it before, during, and after seeding and not damage (most) species of grass seed germination to any large degree.


    I recommend, initially, until about to the point at which you can mow it the 1st time; very frequent but shallow waterings.

    Thereafter, switch this schedulecompletely upside-down (to encourage deeper rooting); by resuming a "normal" infrequent, but deeper watering pattern.
  8. oldlawn

    oldlawn LawnSite Member
    Posts: 4

    Thanks for the thorough explanation Marcos.

    The soil in Southwest VA is mostly red clay. I like the idea of putting down some sand. I imagine it will work its way into the core holes, and help future compacting a lot. My thought was that the compost would do the same, and add some much needed nutrients for old grass and new seed. I'll use a little of both.

    As for weeds, I have some clover (purpleish I believe), chickweed, a little violet, and some broadleaf stuff that usually dies for a while when Ortho broadleaf killer is applied. The undesireable grass is commonly called wire grass here (not sure if that name is correct). It thrives in the heat and runs horizontally.

    I'll spray a good broadleaf killer a few days before I aerate.

    Does grass seed have a shelf life? I bought some in the fall, and have half a bag left.

    I typically get starter fertilizer for new seed. Any better recomendations?
  9. Marcos

    Marcos LawnSite Gold Member
    Posts: 3,720

    Well, starting at the top and working down....

    Your Ortho broadleaf weed killer should be able to handle the broadleaves, provided that they're "up and growing" fast enough when you spray them.

    Remember: (Most) broadleaf weed controls work by accelerating the growth processes within the cell structure of the plant.
    So, if they're "not growing so fast" yet...(because it's maybe kinda early still, and cool)...then the results when you spray them will reflect that same level of control.
    Don't forget to add a teaspoon of dish soap (Dawn, Palmolive, etc) per gallon of spray mix, to work as a surfactant.
    This helps the spray "spread" over the surface better, and not bead-up as much; or "stick" better.

    What you're calling "wire grass" is probably either bermudagrass or zoysiagrass.
    Neither one is going to be fazed by your broadleaf spray mix, no matter how strong or when you spray it.

    (1st of all...to be sure...why don't you post a pic or two of it on this thread...just to make sure we're talking about the same thing?)

    Either zoysia or bermuda have to be eradicated by non-selective herbicides...and if you're in a "hurry" this spring like you say you are...you may as well figure on tackling that windmill at some point in a late summer, or early fall time period...when these grasses are actively growing and can be readily managed by chemicals.

    The timing of your broadleaf spray before your aeration:
    I'd recommend a solid week to 10 days for the herbicide to translocate and kill, before you go in there and start plugging.

    Grass seed stored from last fall should be just fine, provided that it was kept in a cool, relatively dry location; and you didn't have it stored near any bags or containers that have some type of turf or landscape pre-emergent in them.

    Your last Q about starter fert makes my mouth water ! :)
    10-15 years ago I used to be a bigger advocate of starter fert on seed...than I am now.
    But as my business matured I've found that I've had much better successes in this arena by jumping over into the "organic realm" a little bit more.

    I experimented, starting in the renovation season (fall) of 2004, with the spores of endo-mycorrhizae; buying them in a soluble (hydroponic) formulation that I incorporated with nutrient-rich compost tea, and sprayed onto my prepared seed beds as they were being finished.
    Well......the results that fall were absolutely incredible, in terms of the density of the root system of the turf coming in (and ultimately of course, the lawn itself) and since then for my own purposes, I haven't looked back to chemical starters whatsoever.

    You're taking a step toward organics already by your plans of top-dressing w/ compost.
    Endo-mycorrhizae spores can use that compost as food as they "infect" the root system of the turf in your lawn...in a good way !
    The trick is...to get the spores in contact with the roots as much as possible, by applying mycorrhizae (in some form) right after a REALLY THOROUGH aeration.

    What's the "down" side?
    Any weed controls, chemicals you overuse on the lawn later may damage these root-clinging colonies.
    You would be best served to switch from "5 step programs" to a compost tea / protein meal diet for your lawn from that point forward.
    ...and this can be a little bit more expensive, and the stuff can be sometimes a bit hard-to-find.
    But once you turn that "corner" in turf density, and your yard truly becomes *"alive" again.....they'll be no turning back for you, either!

    Check out the "organic lawn care" forum on this site for in-depth discussion on mycorrhizae, teas, etc....

    Here's the place in CA where I buy the spores for my business, if you're interested:
    (I own no stock nor have anything to gain personally by anyone buying from them)

  10. oldlawn

    oldlawn LawnSite Member
    Posts: 4

    Great tip on the dishsoap. Those sprays tend to roll right off the leaves sometimes, espcially with the clover.

    Fairly certian its bermuda and not zoysia.

    Its still a little cool and and nothing is growing that fast except for the established fescue. I may be better off aerating and seeding now, and spraying in a few weeks. I was just hesitant to spray any killer on newly growing grass.

    I'll check out the organic fertilizer route.

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