How to Kill and Prevent Lawn Weeds

Share Button

Lawn weeds are the biggest concern that most homeowners have with their grass. Chemically and organically treated grass have issues with weeds. How to kill lawn weeds like dandelions, crabgrass, clover, speedwell and violets in organic lawn is best done by preventing them in the first place.

Some lawn weeds are more acceptable that others, for example clover. Some are grassy and others are broad leaf. Most can tell you that there is something wrong with your soil.

Lawn weeds are actually smart plants:

  • Some grow low to the ground avoiding the mower
  • Some hurt if you grab them
  • A weed can have roots 3 feet deep so
  • Even if you pull them out it grows back
  • They irritate people with allergies
  • Get into cracks in the driveway causing damage
  • They spread like crazy
  • Wind and birds carry them and it can travel for miles


lawn weed


Nothing is more frustrating than being meticulous about your grass, then looking across at your neighbor and seeing a sea of dandelions. It’s probably even more annoying than their leaves blowing onto your lawn.  A lot of people don’t care if they have lawn weeds.  And that’s okay too.  It does mean more work for you though if you want a really nice lawn.


Lawn Weeds give us a clear indication of what’s wrong with our soil
For example:

  • Clover will indicate our soil is lacking nitrogen. It’s a legume which “fix” nitrogen by taking it out of the air and making N available in the soil
  • Plantain and crabgrass like compacted soils
  • Dandelions are an indication of a soils lack of calcium
  • Sorrel an indication of low pH.

Knowing your lawn weeds and where it likes to grow will help you understand what’s wrong with your soil. So between your soil test and the weed in your lawn you should have a good idea of why lawn weeds are a problem.

We have all your products to get rid of weeds at our lawn care store.

Solve the problem and don’t just treat the symptoms by
spraying lawn weed killer


If nature has open soil available it will naturally plant something there, so beat it to the punch and fill the bare spots in with grass seed. The thicker the turf the less opportunity for unwanted and unsightly growth of a lawn weed.


Overseeding can help get rid of lawn weeds

  • Having thick dense turf
  • Mowing at the correct height
  • Good soil
  • Proper watering habits
  • Will help prevent most lawn problems.

If crabgrass or dandelions seeds don’t have anywhere to take germinate then they’ll just have to grow where they’re welcome.

In your neighbors yard!


Corn Gluten Can Prevent Lawn Weeds Organically


There’s lots of talk about corn gluten being used as organic weed control. Specifically as a preemergent.

  • Problem A: Not that effective unless timed perfectly at germination and many will germinate twice a year.
  • Problem B: It’s 10% Nitrogen and at the suggested effective application rate of 20 pounds per 1000 square feet, it leaves us applying 2 pounds of Nitrogen per 1000 square feet per application and as we talked on our Nitrogen page the maximum for the entire year is 3 pounds. If you’re getting a pound from leaving the grass clippings on the lawn along with what is already in the soil, well it doesn’t make sense.
  • Problem C: It’s expensive!

Preemergent herbicides act against the plant once the seed breaks open and a seedling develops. They do not prevent all growth. Usually preemergents are used kill annual grassy weed problems for that season. A crabgrass seed can survive in the soil for years and is just waiting for the opportunity to take over your lawn area.

Corn Gluten is a good source of organic nitrogen to green up your lawn if applied at 10 lbs. per 1000 sq ft.
weeds in lawnIf you had a crabgrass problem last year then you may want to consider using it but I’d rather see you spend your money on a bag of good seed and renting an over seeder for half a day.

Corn Gluten does become more effective as a weed prevent or each year after repeated applications. Studies show corn gluten reducing lawn weeds by 60% the first year, 80% the following then 90% in the third year. So, as you can see, corn gluten can be effective but at a price. And I don’t mean just your cash!

Stay true to the 1 pound of Nitrogen per 1000 sq. ft

I’m sure one of the reasons you want an organic lawn is for environmental concerns. If you’re applying it at the recommended 20 lbs. per 1000 sq. ft. rate or more, it could create nitrogen leaching and negates any good you’re trying to accomplish.

Very important

Keep in mind, if you do use corn gluten as a preemergent weed control, it will also prevent grass seed from germinating, so they can’t be used together.

New products are consistently arriving on the market that try to appease both sides of the organic argument. Concerning our topic here, we’re talking about a synthetic weed killer combined with an organic fertilizer.

These are called bridge products.  On this website we limit use of synthetic pesticides, but transitioning from conventional lawn care to organic can get a bit difficult with regard to annual grassy weeds (crabgrass etc.)
Depending on your situation and what I mean by that is:

  • Your time
  • Your finances
  • Your physical conditioning
  • Your patience

I’d rather see you cheat a little bit at the beginning and succeed in the end rather than get frustrated, then give up and go back to synthetic fertilizers and herbicides.

Regardless of which path you take, over seeding your lawn should become your #1 defense against unwanted lawn weeds!

Over seeding your lawn in late summer/early autumn in cool areas and late spring/early summer in warm areas is imperative when beginning the organic transition. If you don’t have a chance to do it then, overseeding your lawn in the spring with annual rye grass is a good alternative preventing lawn weeds. It’s inexpensive and it fills in the bare spots until you renovate later that summer.

Just make sure you do it early enough before the weed seeds germinate which is when the soil reaches 50 degrees or about when Forsythia shrub is done blooming in cooler zones.

Using An Over Seeder Is Easy

prevent lawn weedsRent one that is hydraulic or self propelled. Set the depth to 1/4 inch, put in your seed and just go back and forth as you would mow a lawn and then repeat perpendicular to your first direction.

Keep the seed moist until the third mowing.

It’s not a cure-all and it will take a bit of time but I think it’s the best remedy.


How to get rid of lawn weeds

What about the big leafy lawn weeds? Well, there is horticultural vinegar based organic weed killer available which a is pretty effective way to get rid of weeds.

Using them in the heat and while the weed is actively growing. They are a non-selective herbicide meaning any vegetation that comes in contact with it will be affected.
Don’t use on a windy day or that precious plant in the corner might end up in the compost pile.


Very important is that you wear gloves and eye protection when using horticultural vinegar!

Just because it’s organic doesn’t mean it’s harmless. Get horticultural vinegar in your eye and believe me your going to be bumming, so please use precautions.

It is effective as a weed killer and works quickly but like I stated it affects any grass or plant surface it touches.

Once the weed dies rake it up, pull it up, put down a little loam, compost mix then seed, spray with a little compost tea and then keep it moist until the bare spot fills in.

Another effective organic way to eradicate the lawn weeds is to simply bend over and pull them out…then seed as stated above.


  1. I switched this year to organic lawn which right now the yard looks great, very thick. I have mowed the grass at 4″ this year and my question is what should I do for winter…do I leave it at 4″ or should I mow it down to 21/2″ to 3″ for winter months?
    I live in central PA.

    Thanks Todd

  2. Great to hear you are having success Todd. I would mow the lawn down approx. 2 – 2.5 inches for the winter months. Remember also to bag the first mowing of the following spring to prevent any spread of mold issues from the winter.

Leave a Reply

Your email address will not be published.