Using A Lawn Pre-emergent

Joined
Sep 2, 2005
Messages
10,237
Location
MIchigan
I have never used a Lawn Pre-emergent before and after watching videos of people that do........ it still doesn't make sense to me.
So you buy this Pre-emergent and apply it to the lawn and it prevents (doesn't kill ) weeds from coming up. So basically your trying to prevent weeds from coming up that may or may not grow in the areas that you apply the pre-emergent . Isn't it more economical to just fertilize to choke out the weeds and and apply a Liquid Weed Killer ? What are your thoughts ?
 
They DO WORK. DON'T OVERAPPLY. It will, burn your grass beyond recovery. So as you are walking up and down the lawn-keep your "rows" straight. Most also have an ingredient that allows for a quicker "green up" in the spring.
 
They do help get control of weeds so there's less to kill later, and that "ingredient that allows for a quicker green up" is called nitrogen fertilizer. ;) If you were going to fertilize your lawn anyway, it's not an extra step to apply the combo product.

However, fertilizing your lawn does not effectively choke out weeds. Weeds grow faster from fertilizer too.
 
I have trashy neighbors on two sides. One has literally 80% weeds, and lets it grow to 8"+, the other 20% weeds and cuts at 6" or so.

I spent dozens of hours hand-spraying my .7 acre.

Then I found The Andersons pre-emergent, and I now literally have maybe 30 weed plants in-total in the back .5 acre, with another 20 or so in the street-adjacent ditch. I walked around the back yard a couple weeks ago, and maybe 10 dandelions had sprung up.

Pre-emergent made a huge change in my life. And I now don't care about the state of the neighbors lawns.
 

Attachments

  • PXL_20220918_200448931.MP.jpg
    PXL_20220918_200448931.MP.jpg
    251.3 KB · Views: 29
The rule of thumb in the spring is to apply the pre-emergent when you first see the forsythias bloom, timing is everything. If you plan on grass seeding, you need to select a pre-emergent safe for seeding. It's spring application is best for preventing crab grass from sprouting later on.
 
Turf weeds can be either broadleaf (ie, dandelion) or grass (ie, crabgrass). There are annual weeds (complete cycle in 1 year), biennial (2 years), and perennials (many years). Weed seeds can remain viable in the soil for decades, until conditions become "perfect" and they germinate. I.E., soil disturbance and exposure to sun can activate old weed seeds to germinate.

There are soil active herbicides and leaf contact herbicides (some are both). Some herbicides are very selective and some kill everything. I.E., 2-4D will kill broakleafs and not grass while glyphosate (Roundup) will kill nearly everything.

Pre emergent soil herbicide only prevents weed SEEDS from germinating and developing. It soaks into the ground surface to form a "cap" that prevents weed gernination development. Perennial dandlelions or quackgrass and bienials all with established roots will NOT be killed by a preemergnent herbicide.

@cmarshall78 - there ARE postemergent (crab)grass herbicides now. Quinclorac is an example: https://www.canr.msu.edu/news/controlling_crabgrass_after_it_emerges (Hebron is a great place, but beware that it is south of Merrillville and poo flows downhill, LOL).

Maintaining healthy dense turf helps prevent weed seed germination and crowds out broadleafs to an extent. The IPM (Integrated Pest Mgmt) goal is to reduce the use of pesticides and fertilizer. Choose turf varieties robust for your conditions (soil, climate, etc.). Practice good cultural methods (don't bag clippings, mow correct height, water correctly). Fertilize correctly (timing, amount). Accept some weeds in your lawn. The goal is to reach a point that you are not applying pesticides annually - maybe every several years if things get out of hand. IMO, shoot for "good enuf" and don't become a slave to your lawn. Moderation. It's much better for the environment and you.

Study your state's extension site for local education and practices.
 
Last edited:
FWIW I use the Menards branded 4 step program and my yard is the nicest on the block. I spend way less than my neighbors do on a full service.

The first treatment is for crab grass. I believe this to be a pre emergent treatment. It prevents the crab grass from growing.

Just my $0.02
 
Turf weeds can be either broadleaf (ie, dandelion) or grass (ie, crabgrass). There are annual weeds (complete cycle in 1 year), biennial (2 years), and perennials (many years). Weed seeds can remain viable in the soil for decades, until conditions become "perfect" and they germinate. I.E., soil disturbance and exposure to sun can activate old weed seeds to germinate.

There are soil active herbicides and leaf contact herbicides (some are both). Some herbicides are very selective and some kill everything. I.E., 2-4D will kill broakleafs and not grass while glyphosate (Roundup) will kill nearly everything.

Pre emergent soil herbicide only prevents weed SEEDS from germinating and developing. It soaks into the ground surface to form a "cap" that prevents weed gernination development. Perennial dandlelions or quackgrass and bienials all with established roots will NOT be killed by a preemergnent herbicide.

@cmarshall78 - there ARE postemergent (crab)grass herbicides now. Quinclorac is an example: https://www.canr.msu.edu/news/controlling_crabgrass_after_it_emerges (Hebron is a great place, but beware that it is south of Merrillville and poo flows downhill, LOL).

Maintaining healthy dense turf helps prevent weed seed germination and crowds out broadleafs to an extent. The IPM (Integrated Pest Mgmt) goal is to reduce the use of pesticides and fertilizer. Choose turf varieties robust for your conditions (soil, climate, etc.). Practice good cultural methods (don't bag clippings, mow correct height, water correctly). Fertilize correctly (timing, amount). Accept some weeds in your lawn. The goal is to reach a point that you are not applying pesticides annually - maybe every several years if things get out of hand. IMO, shoot for "good enuf" and don't become a slave to your lawn. Moderation. It's much better for the environment and you.

Study your state's extension site for local education and practices.
Actually pre-emergent don't prevent germination rather it prevents the roots from developing once the seed has germinated.
 
Last edited:
All crabgrass dies in the winter, its an annual weed. Every year/spring the new crabgrass seeds germinate (if you have crabgrass in your area).
Putting down pre-emergence saves you the time and effort of dealing with it in the warm summer months when it can get out of control almost over night as the crabgrass will be prevented from growing..
Timing the pre-emergence application is important not too early and not to late that the seeds already germinate. The pre-emergence if timed right will last the summer if not some will still germinate in August, sometimes two applications in spring/early summer with an all in one fertilizer and preeminence is best.
There its also a triple combination lawn food, pre-emergence, weedkiller in one bag.
Of course a nice thick well cared for lawn (Zoysia) will make lawn maintenance a simple chore and the talk of the community. (Like ours ;)) ... and we do not use a lawn service.
Even so I still put down at least once in the later spring a combo application mentioned above. Then plain fertilizer during the season.

IMG_9542.jpeg
 
Last edited:
Pre-emergent should be applied when the soil temp is 55F. When the forsythia are in bloom.

There are only two pre-emergent worth using. One is prodiamine (Barricade) and the dithiopyr (Dimension). Forget Scott's Halts or anything else.

The pre-emergent does not last forever. It really should be applied a second time to prevent the weeds all summer.

Dithiopyr can also kill weeds that have already started to grow. But they need to be very small.

And if your going to seed or overseed you cannot use a pre-emergent.
 
All crabgrass dies in the winter, its an annual weed. Every year/spring the new crabgrass seeds germinate (if you have crabgrass in your area).
Putting down pre-emergence saves you the time and effort of dealing with it in the warm summer months when it can get out of control almost over night as the crabgrass will be prevented from growing..
Timing the pre-emergence application is important not too early and not to late that the seeds already germinate. The pre-emergence if timed right will last the summer if not some will still germinate in August, sometimes two applications in spring/early summer with an all in one fertilizer and preeminence is best.
There its also a triple combination lawn food, pre-emergence, weedkiller in one bag.
Of course a nice thick well cared for lawn (Zoysia) will make lawn maintenance a simple chore and the talk of the community. (Like ours ;)) ... and we do not use a lawn service.
Even so I still put down at least once in the later spring a combo application mentioned above. Then plain fertilizer during the season.

View attachment 117590
That's a Nice Home You Have
 
Actually pre-emergent don't prevent germination rather it prevents the roots from developing once the seed has germinated.
yea, I know that, but didn't take the effort to word it correctly beyond "germination and development" to get the general idea out. My bad.
 
That's a Nice Home You Have
Thank you! We loved our home here in SC for the last 16 years, we love the state too (The state really is the land of the free/home of the brave), had it built new and moved from what is the insanity of my home town on Long Island, NY though I LOVED growing up there and wouldnt trade those memories for anything.
Well, after 16 years here in SC we are selling this one and moving to the coastal area of NC with a new and much smaller home under construction to be completed by early next year. Kids now off on their own, as much as we love this home and hate to give it up, moving forward as we get older its a lot to maintain and clean more than we would like, 5 BRs (3000 sq ft)
I guess a lifestyle change and change of maintenance and convenance, meaning we got spoiled since moving south having a new home and was a decision should we do a total makeover on this home or move (gulp) as we move forward into our retirement/almost years to a everything new home again and what we think will be a new, more exciting lifestyle ... by spring I guess we will know. Was NOT an easy decision. A few months back we almost moved to northern Florida and chickened out, still have the unsigned contracts in my inbox.
This one in NC we are fully in contract and technically could back out at anytime with a bit of a sting possibly losing the downpayment.
But I am getting used to the idea and looking forward but still an uncomfortable feeling at times.
 
Last edited:
Turf weeds can be either broadleaf (ie, dandelion) or grass (ie, crabgrass). There are annual weeds (complete cycle in 1 year), biennial (2 years), and perennials (many years). Weed seeds can remain viable in the soil for decades, until conditions become "perfect" and they germinate. I.E., soil disturbance and exposure to sun can activate old weed seeds to germinate.

There are soil active herbicides and leaf contact herbicides (some are both). Some herbicides are very selective and some kill everything. I.E., 2-4D will kill broakleafs and not grass while glyphosate (Roundup) will kill nearly everything.

Pre emergent soil herbicide only prevents weed SEEDS from germinating and developing. It soaks into the ground surface to form a "cap" that prevents weed gernination development. Perennial dandlelions or quackgrass and bienials all with established roots will NOT be killed by a preemergnent herbicide.

@cmarshall78 - there ARE postemergent (crab)grass herbicides now. Quinclorac is an example: https://www.canr.msu.edu/news/controlling_crabgrass_after_it_emerges (Hebron is a great place, but beware that it is south of Merrillville and poo flows downhill, LOL).

Maintaining healthy dense turf helps prevent weed seed germination and crowds out broadleafs to an extent. The IPM (Integrated Pest Mgmt) goal is to reduce the use of pesticides and fertilizer. Choose turf varieties robust for your conditions (soil, climate, etc.). Practice good cultural methods (don't bag clippings, mow correct height, water correctly). Fertilize correctly (timing, amount). Accept some weeds in your lawn. The goal is to reach a point that you are not applying pesticides annually - maybe every several years if things get out of hand. IMO, shoot for "good enuf" and don't become a slave to your lawn. Moderation. It's much better for the environment and you.

Study your state's extension site for local education and practices.
Great reply. Generally a preemergent is to stop annual monocot weeks, e.g. crabgrass in the germination stage. A broad leaf post emergent product is used for the weeds you see actively growing in your lawn.
 
I refuse to use that stuff. I have a centipede turf lawn. We do have a LOT of weeds in the spring pop up and my wife gets on my tail about it. I tell her to hold on...

About May, I will mix up 8-12 gallons of spray using Celcius WG herbicide and some of that blue stain/marker and spray it all over our yard (~1 acre).

About 3 weeks later, the weeds are gone, I've put out some fertilizer and the yard looks great, wife isn't complaining anymore. I would have to do all of this if I put down a pre-emergent..... How do I know? Because I've done it. I'll have to apply the Celcius again in late August or so, if we have decent rain through the summer, but that's it.

The Celcius is not Home-Depot grade, weak garbage. It's professional-grade, high-quality stuff that WORKS. It's not cheap, either, that's why you've probably never heard of it. The name is now owned by Bayer, but they don't have the stones to try to get a big box to sell it....
 
Back
Top