Pre-emergent Noob Question

Discussion in 'Pesticide & Herbicide Application' started by Michael Ray, Feb 18, 2018.

  1. Michael Ray

    Michael Ray LawnSite Senior Member
    Messages: 346

    I'm in NC. Am I wrong or are the preemergents that are available mostly for annual grasses such as crabgrass? I realize they hit a few broadleafs but isn't the recognized method for broadleaf control to use post emergents?
  2. Digitaria Sanguinalis

    Digitaria Sanguinalis LawnSite Member
    Messages: 182

    If broadleaf weeds are your concern not much better than Isoxaben. Specticle has a wide range as well. What's your budget? Type of grass? And how many square feet?
  3. Michael Ray

    Michael Ray LawnSite Senior Member
    Messages: 346

    While I appreciate the answer you didn't really answer my question. Am I completely wrong about pre vs. post emergents for broadleafs?

    My question probably could have been clearer as well.... I'm asking this question in regards to use on turf...specifically in the south.
  4. Digitaria Sanguinalis

    Digitaria Sanguinalis LawnSite Member
    Messages: 182

    It's always cheaper and more effective to stop weeds before they germinate. Your question in very subjective. Without knowing what broadleaf weeds you speak of annual vs perennial I can not give you a definite answer. Like I said above if you want to stop annual broadleaf weeds use Isoxaben. The only way to gain more knowledge as a self proclaimed "noob" is researching the labels and reading a turf management text book. Good luck
    GrassManKzoo and hort101 like this.
  5. RigglePLC

    RigglePLC LawnSite Fanatic
    Messages: 14,453

    Michael, you are correct. Broadleafs are usually controlled with a post emergent herbicide like the usual Trimec.
    Depends on the situation. Grass species, climate, cost and weed type will influence the choice.
    GrassManKzoo and Michael Ray like this.
  6. kemco

    kemco LawnSite Bronze Member
    Messages: 1,386

    There are some pre emergent that do work better on broadleaf weeds than grassy and vice versa. And like DS replied there are also broad spectrum that do a pretty good job on both. If u are asking what I think, the answer is still unfortunately "it depends". Regardless of grassy or broadleaf, pre emergent are not going to really have much effect at all on perinials due to the method of how a pre emergent works... They do not stop germination, but rather stops the formation of the fine roots which form right after germination. So broadleaf or grassy doesn't matter. The perinials will already have an established mature root system and will be able to survive being hit with preemergent. Now back to the question of whether there are/is a preemergent that is effective on certain or most broadleaf annuals... Yes there are. Going back to reiterate what DS replied here is where cost is reward come into play. Its been my experience that the better (the more broadleaf and grassy weeds controlled) the preemergent the more it's going to cost you. I'm quite a bit south of you so we may not be using the same products. We have had very good results with Specticle but it is $$$ compared to others. Lastly, we don't just use one type of preemergent. We use 3, and which one(s) used depend on the season, temp, and what timing we need to control the target pest/weed. Hope some of that helps, long winded answer... Sorry.
    Michael Ray likes this.
  7. takervader

    takervader LawnSite Member
    from Alabama
    Messages: 140

    Really depends on what you're trying to get rid of. I put down pre religiously and don't get many broadleafs. I only seem to get the annoying ones like Dallis or buttonweed.
    hort101 likes this.
  8. Michael Ray

    Michael Ray LawnSite Senior Member
    Messages: 346

    Thanks everybody. Yeah so pre will help with the annuals and annual grass, post will help with perennials. I appreciate it. One last question, any suggestions for a selective spot treatment for a wide variety of broadleafs that won't break the bank or kill the turf?
  9. takervader

    takervader LawnSite Member
    from Alabama
    Messages: 140

    I typically do a 3-way plus something else, this time of year its Metsulfuron-methyl (AmTide/Blindside).
  10. BigJlittleC

    BigJlittleC LawnSite Silver Member
    from Chicago
    Messages: 2,881

    A quality preemergent will stop the listed weeds before they take hold. Annual or perennials doesn't matter. While post emergent will kill listed weeds after they have started to grow.

    Any quality program will use both pre and post to achieve a weed free lawn. Also if your starting with healthy thick turf using preemergent correctly will reduce the use of post products.
    ltdlawn and hort101 like this.

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