Getting rid of crabgrass

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Getting Rid Of Crab Grass

Does everyone hate and need help getting rid of crab grass? No!
Believe it or not, there are three categories of people who actually want this troublesome weed. This article is for everyone else.

Folks fond of the tenacious spirit of crabgrass are:

  • Farmers growing summer forage crops for cattle.
  • Environmental agencies cleaning up oil spills.
  • Homeowners who wouldn’t have anything green in their yard if it wasn’t for crabgrass!

So now that we know crab grass isn’t everyone’s nemesis, do you need ideas for keeping it out of your lawn or yard?

Weed problems don’t happen overnight, though you might swear they do. Getting rid of crab grass won’t occur quickly either. But it is possible to eliminate now and prevent or lessen its reappearance each year.
If you are not certain that crabgrass is the demon you face, take a moment to find out, in this article What Does Crabgrass Look Like.

Also, take a look at a series of useful crabgrass photos in this gallery Crabgrass Pictures.

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Why Is Crab Grass Such A Nuisance?

Crab grass is an annual weed, but it acts like a perennial. It has what is called an indeterminate growth pattern. Most annual weeds grow until mature enough to produce seeds, then they die. They have one shot to reproduce.

Getting rid of crab grass is difficult because it keeps growing all season, spring through fall. New plant growth, developing seed heads, and mature seeds will all be present on a plant throughout the warm seasons.

Mowing the crabgrass won’t stop it, or even slow it down. It will grow more flat, rather than upright. But it keeps producing seeds, week after week, until you kill it or cold weather arrives.

Crab grass is prolific. It can produce over 150,000 seeds per plant. These seeds won’t germinate till the next season. It may seem like new plants are popping up from the current seeds. Actually, this just reflects the long window in which crabgrass will start to grow. Any attempt at getting rid of crab grass has to take this into account.

Seed germination depends on certain soil temperatures, anywhere from 50 to 75 degrees. When this happens will vary in different parts of your yard. It is affected by sun exposure, shading, moisture content, and more. I’ll explain later how this can be used to your advantage.

The one thing to realize from this is that the longer you wait in the season to kill crabgrass, the worse your problem will be next year. If you do nothing during the growing season, plan during the winter for an early start to your battle for control. But even if this weed has the upper hand now, don’t give up!

Steps To Getting Rid Of Crab Grass

Once this troublesome weed has gotten started in your yard, there are several things you can do to get control over it. The step or stage that is best for starting will depend on the season in which you begin.

  1. Keep crabgrass seeds from spreading.
  2. Kill existing crabgrass.
  3. Remove dead crabgrass plants.
  4. Replant bare lawn spots with new grass seed.
  5. Apply a crabgrass preventer at the appropriate times.
  6. Set your lawnmower at the high end of the range that is best for your grass type.
  7. Restrict excess fertilizing or too-frequent watering.
  8. Keep your lawn healthy as the most conducive way to get rid of crabgrass.

The explanation for each of these steps follows below.

1. Crabgrass Control Through Seed Control

During the warm months, getting rid of crab grass problems in the future should be your goal. Try to prevent the formation and spread of crabgrass seeds.Before mowing, use a lawn rake to disturb the crabgrass from its prostrate position.

Like running a comb through your hair the wrong way, use the rake to cause the seed branches to stand up above the grass.

This might be a tedious chore, but can eliminate 2 or 3 times as many seed heads as a regular mowing over hidden stalks.

After raking, mow the lawn as soon as possible. Be sure to use a grass catcher. Normally, a mulching mower that returns clippings to the soil is a good idea. That won’t help when your goal is getting rid of crab grass seeds.

Can you put these clippings, with seeds, into a compost pile? Only if you actively work the pile, turning it regularly to generate enough heat to kill the seeds. If you add to your garden beds any compost with the seeds not killed, guess what? Crabgrass seeds can remain alive for years in the soil, and germinate even at depths of 2” – 3”.

Your best bet at this time may be to recycle your clippings through the local yard waste collection. This is not a technique to pursue long term. Just utilize this practice at the beginning of your “crabgrass war”, until you have killed or removed the weeds.

2. How To Kill Crab Grass

The method of choice for getting rid of crab grass that is currently growing will depend on several factors.

Is it a lawn area, flower beds or vegetable garden?
How large is the affected area?
Is conserving time, energy or money most important?
What tools, equipment or products are available to you?

A complete analysis of these concerns will help you determine the best approach. Read this article, How To Kill Crab Grass.

3. Remove Dead Crabgrass Plants

Getting rid of crab grass plants after they die is just as important as killing the weed. The dense mat that crabgrass forms can smother nearby grass plants. Removing the dead plant in a timely manner may allow your lawn grass to recover.

Crab grass is a type of plant that has an allelopathic effect. This means it releases a toxin that suppresses the growth of other plants. How long does this effect last after the crabgrass is dead? That is unclear, but the prudent action would be to eliminate any negative effect on your desired plants.

4. Replant Bare Lawn Spots

When soil is exposed in your lawn area, all types of weed seeds are likely to germinate and take hold. Plan to reseed these open areas in your lawn as soon as possible to eliminate opportunity for more trouble next season.

Early in the fall season is a great time to start new grass. It should have plenty of time to get established before winter. The spring season is NOT a good time to reseed grass IF you plan to use a preemergent as a crabgrass preventer.

Cover non-lawn areas with a thick layer of mulch to reduce the likelihood of weeds growing. At least one inch thick will help, but two inches is better. Any weeds that still sprout through this will be very easy to eliminate by pulling or spraying.

5. Crabgrass Prevention

You’ve embarked on the lengthy journey of getting rid of crab grass. The most important part of your success comes with preventing the next infestation.

The easiest way to do this is by using a preemergent. This is simply a product that will inhibit the crabgrass seedling as it starts to grow. Both chemical and natural products are available.

Timing is always important with pre-emergents, but crabgrass is a bit different from most common weeds. The generic advice you may hear may need to be tailored to fit your situation. Learn some useful facts in this article, When To Apply Crabgrass Preventer

6, 7, 8. Best Lawn Maintenance Practices

A healthy lawn growing on healthy soil does an exceptional job of resisting a crabgrass infestation. The time, effort and expense of getting rid of crab grass could instead be put into building a resistant lawn environment.

When cutting your lawn, don’t mow too low! Taller grass will shade the soil and make it less hospitable for many weed seeds to develop. Most grasses do well at a mowing height of 2” to 3”, and some varieties even higher.

Crabgrass responds favorably to nitrogen applications. Meaning, if you are growing for cattle forage, throw the fertilizer on. But restrict fertilizer applications on the typical home lawn when your goal is getting rid of crab grass. Find some valuable guidelines in a series of articles on Fertilizers.

Abundant moisture makes a prime germination setting for weeds. Avoid daily watering of lawns that keeps the soil constantly moist on top. Deep irrigation done less frequently will promote deeper roots, healthier grass, and fewer weeds.

Do you currently employ a lawn service company? Ask if they rinse/blow off their mower at previous job sites. You don’t want them bringing weed seeds from a problem lawn. (Make them answer the question, not sidestep it by saying, “Oh, none of our customers have crabgrass!” To that you may respond, “Oh, and what about their neighbors?”)

If you are considering bringing on some professional help, for a project like this or regular maintenance, get more tips like this and be completely informed. You deserve to get the full value from your expenditure.

As this lawn care site develops, you will discover all you need to build, renovate, or maintain a healthy lawn. And yet for some of you, a time comes when you may want to ask for professional help… (or move to an apartment?)

Dig into these two free guides for smart tips on lawn care help,
if you think it may be time to call in the cavalry:

Which Lawn Care Services Might Be Right For You?

What To Expect, and Demand, from Lawn Care Companies

Be sure to check back in the weeks and months ahead and take advantage of more helpful information as it is submitted.

Crabgrass — the bane of many homeowners — is a troublesome plant. Not only does it outgrow and outcompete more polite lawn grasses, it can actually poison other plant competitors, according to a study in the Journal of Agricultural and Food Chemistry.

Its numerous seeds lurk on and in the soil for up to three years, germinating whenever the temperature rises above 55 degrees and sunshine reaches the moist soil. And even though the Digitaria genus are annuals, the bare spots they leave behind in your lawn provide perfect places for germinating more seedlings the following spring.

Before you reach for the pesticides, try these four other ways to remove the weed.

1. Reduce Seed Production

PICSUNV/getty

Pull out as many plants as possible early in the season before they can set seed. Mowing can buy you time to remove plants. If there are large patches, you can naturally kill midsummer weeds using an herbicide containing ingredients such as clove oil and citric acid. Just remember it will kill any plant it touches.

2. Prevent Seed Distribution

ablokhin/getty

Bag any plants or clippings and immediately discard them (don’t throw them in the compost pile or use as mulch!) in the landfill. Another option is to tie the top of the bag and leave it in a sunny place for four to six weeks, which will let the heat kill any seeds. After that, it’s safer to compost.

3. Suppress Germination

BrianAJackson/getty

A thick, healthy lawn is the best defense against crabgrass. When the ground is densely shaded, the seeds can’t germinate. There are a number of ways to improve the health of your grass, but here are a few initial suggestions:

  • Set your mower at the top of the recommended height range for your type of lawn. Quicker-growing crabgrass will have a harder time outcompeting the rest of your lawn.
  • When watering, do it deeply but infrequently. This will allow the surface of the soil to dry out, killing the shallow-rooted crabgrass.
  • Fall is a good time to plant lawn grass in areas with cold winters, as frost will soon kill any crabgrass seedlings.

If your lawn is thin, you can spread corn gluten (20 pounds per 1,000 square feet) in the spring or before the beginning of the rainy season. Corn gluten inhibits the germination of seeds and breaks down rapidly, leaving nitrogen to feed established grass.

4. Solarize the Soil

Wulf Voss / EyeEm/getty

If you’re still having trouble killing seeds, you can try this nifty trick: In the warmest, sunniest part of the year, mow the plants as short as possible, water generously, and then cover the area with a sheet of clear plastic.

Seal the edges all the way around by digging a shallow trench and covering the perimeter of the plastic with soil. Take care not to puncture the sheet and leave it in place for four to six weeks. The plastic will heat up the ground enough to kill all seeds underneath. You can then reseed the ground with the grass you want afterward.

How to Get Rid of Crabgrass in the Summer

Lush, green lawns are a summertime staple. We spread fall fertilizer and sprinkle lots of grass seeds in anticipation of thick and healthy turf.

But some things that help our lawns look pristine can fall through the cracks—like the all-important pre-emergent herbicide.

If you didn’t apply pre-emergent in spring, your lawn can become overrun by crabgrass. While it is best to stop crabgrass before it sprouts, you can try to get rid of it in summer with these steps!

How to Kill Crabgrass in Summer (With and Without Chemicals)

What does crabgrass look like?

Crabgrass is a course, clumpy weed that looks like yellow or green grass blades. Not only is it unattractive, but it’s also bad for your lawn’s health.

Why is crabgrass bad?

Crabgrass has a way of taking over turf and making it harder for healthy grass to grow. That’s because the weed outcompetes grass for limited nutrients.

How to Get Rid of Crabgrass Without Chemicals

Crabgrass dies on its own each year in fall. If you can wait it out, the weed will be gone by winter, and crabgrass won’t return if you apply a pre-emergent next spring.

Or you can pull out small crabgrass infestations by hand. Then, follow it up with healthy lawn care habits to lessen its chances of returning.

Here’s how:

  1. Pull the crabgrass up—roots and all. If it’s difficult to remove, water the lawn to loosen the soil.

  2. Seed the lawn to fill bare areas. If you recently used a weed killer on your lawn, wait at least a month before reseeding.

  3. Deeply water your lawn one or two times per week.

  4. When mowing, keep the grass at about three inches tall. Then, leave grass clippings behind to add natural nutrients and shade for the soil.

  5. Next spring, apply a pre-emergent around the time your flowers and trees bloom.

Killing Crabgrass with a Post-Emergent

If crabgrass is taking over your lawn, a chemical treatment is likely the better option. It would take forever to hand pull all those weeds!

But, some states restrict this option to licensed professionals. Be sure to check local regulations and call in a local arborist, accordingly.

Keep in mind, too, that applying a post-emergent on your own can be tricky. Some herbicides can harm your grass if used incorrectly, and you must use a treatment made for the specific turf you have for best results. Plus, once crabgrass is bigger than a shoot or two , timing your post-emergent applications is difficult.

Late summer in the Midwest means crabgrass. Some summers are worse than others for this hot-weather nuisance grass. And this summer has proven to be a good one for crabgrass, meaning a bad one for lawns. Fortunately, an organic approach to control crabgrass can work over time to reduce its presence.

Control crabgrass organically and sustainably without using toxic, ineffective herbicides.

In order to control crabgrass, it’s important to understand what’s going on in your lawn this time of year as well as how crabgrass grows.

About Summer Lawns:

  • Summer brings quite a bit of stress to lawn grasses.
  • Heat and drought, such as the conditions we’re currently experiencing, damage the lawn.
  • Add to that the fact that we aren’t as forgiving of the lawn’s appearance in the summer as we are in the winter.
  • We want our lawns lush and green in the summertime for outdoor activities.
  • We try to fight nature by continuing to fertilize, water, and coax new growth out of our lawns no matter what the weather.
  • Cool-season grasses, such as the fescue, bluegrass, and rye found in Midwest lawns, grow best when temperatures are in the 60-degree range.
  • Once temperatures get into the 80s and above, lawns will begin to struggle a little.
  • Growth slows, color fades, and lawns will show signs of wear and tear as they are less able to recover from stress and traffic.
  • Some cool-season lawns will even go dormant in the summer, looking brown and brittle until early fall when they bounce back.

Be sure to put down desirable grass seed on bare patches as you see them.

Now here are some facts about crabgrass:

  • Crabgrass is an annual weed.
  • It grows from seed each year.
  • Crabgrass loves hot, dry weather and thrives in temperatures of 80 degrees and hotter.
  • Furthermore, crabgrass picks up steam just as lawn grasses are slowing down.
  • Crabgrass will take advantages of bare patches in the turf.
  • It loves hot areas by paved driveways and walkways.

Luckily, you don’t have to resort to using harmful, toxic herbicides to control crabgrass. These unsafe chemicals may kill the crabgrass on the spot, but don’t actually control crabgrass in the future.

Since crabgrass seed needs light to germinate, mow 3″ or higher, and be careful not to scalp your lawn.

Here are some tips on how to control crabgrass, organically and sustainably:

  • Pull it: Pull out the crabgrass by hand or spot treat with an organic herbicide. And cover bare areas immediately with sod or seed.
  • Mow high: Mow no lower than 3″ from spring on. Crabgrass seed needs light to germinate. Taller grass shades the soil and keeps it cool, minimizing germination of weed seeds. Crabgrass takes off when people mow too low or scalp a patch in summer. When you open up the light canopy in the lawn, more crabgrass seeds germinate.
  • Seed: Put down desirable grass seed on any bare patches as you see them. And we recommend overseeding your entire turf in fall.
  • Prevent: Fertilize with corn gluten meal in the spring. Studies show that corn gluten has some pre-emergent benefits. That means it prevents seeds from germinating, so applying it at the right time of year will control crabgrass and other undesirable turf plants.
  • Bag it: At Greenwise, we don’t usually like to remove clippings from the lawn. But if you have a lot of crabgrass, bag your clippings when you mow the crabgrass this time of year. Get rid of the crabgrass seeds and you will prevent them from germinating in your lawn.
  • Keep calm: Don’t get too wrung out about killing crabgrass in August. It’s going to be dead at the first frost, anyhow. It’s an annual grass.

The off-season is a crucial time to take steps to control crabgrass in the future

Finally, for more information on how to control crabgrass safely and sustainably, please read about Greenwise’s Organic Lawn Care Program.

How to Kill Crabgrass and Prevent it from Returning

Killing Existing Crabgrass Plants

Once seeds germinate and crabgrass sprouts emerge, pre-emergents no longer work. Then it’s time for “post-emergent” herbicides, which target plants instead of seeds. Crabgrass killers are designed to kill existing, actively growing crabgrass plants before they can produce more seed.

When using crabgrass killers or any herbicides, it’s important to understand whether the product is a “selective” or “non-selective” herbicide. Selective herbicides target specific weeds or plant categories, such as grassy plants versus broadleaf plants. Non-selective herbicides kill all plant types, including lawn grasses and other plants you want to keep.

Because crabgrass is a grass, most combination herbicide and lawn fertilizer products, known as weed & feed fertilizers, generally won’t kill it. These products typically include selective herbicides that kill broadleaf weeds, such as dandelions and other common lawn weeds, and keep grasses unharmed. Actively growing crabgrass in your lawn calls for selective, post-emergent herbicides, such as Image All-In-One Lawn Weed Killer or Image Herbicide Kills Crabgrass, that kill crabgrass and leave your lawn grass untouched.

Always read product labels carefully, and make sure the label lists your lawn grass type as approved. Some lawn grasses, such as centipede grass and St. Augustine grass, are susceptible to herbicides that don’t harm other lawn grasses. Whenever treating lawn weeds with herbicides or weed & feed fertilizers, follow label instructions thoroughly, including safety precautions to protect pets, kids and adults.

When crabgrass threatens to disrupt your lawn, you can take control, break the cycle and prevent its spread. Pennington is committed to providing you with the finest in quality lawn and garden products along with expert advice to help you achieve the lush, healthy, weed-free lawn you desire.

Pennington is a registered trademark of Pennington Seed, Inc.

Image and UltraGreen are registered trademarks of Central Garden & Pet Company.

Sources:

  1. UMass Extension Turf Program, “Biology and Management of Crabgrass,” University of Massachusetts Amherst, May 2011.
  2. Perry, Leonard, “Crabgrass Control,” University of Vermont Extension.

Photo Credit:

  1. NY State IPM Program at Cornell University, CC BY 2.0
  2. NY State IPM Program at Cornell University, CC BY 2.0

How to Get Rid of Crabgrass: Prevent and Control Crabgrass

If the crabgrass seeds have already sprouted and crabgrass has appeared in your grass, the pre-emergent herbicide will do no good. However, you still have an option. Post-emergent herbicide products control crabgrass after it has already germinated.

Post-emergent herbicides work by killing the crabgrass plants. Apply these herbicides only to the crabgrass that is visible. Read and follow the manufacturer’s directions on the product carefully. The amount of post-emergent herbicide that you can safely apply to your lawn depends on the type of grass you have. Here are some tips:

• Check the weather forecast before using a post-emergent herbicide. Apply the herbicide on a calm, sunny day. Rainfall shortly after application will wash the product away before the crabgrass has a chance to absorb it.

• For best results, apply the herbicide in the morning after the dew has dried. If you wait until late afternoon, dew or a shower may prevent maximum absorption.

• Post-emergent herbicides work best when temperatures are 60 – 90°F. These higher temperatures cause the plants to absorb the herbicide quickly; if the temperatures are too cool or weather conditions are too cloudy, the product is likely to be ineffective.

• Make sure the soil is moist before applying the herbicide. If not, you should water the area fairly extensively the day before treatment. If conditions are extremely dry, you may want to water again two days after the application. The waiting period will give the crabgrass time to absorb the herbicide.

• If you notice the lawn browning suddenly, you may have applied too much herbicide. In this case, water the area extensively as soon as possible to dilute the herbicide and keep it from further damaging your lawn.

• After treating the area with the herbicide, keep an eye out for newly germinated crabgrass plants. Any plants that may have germinated since the initial application will require a follow-up spot treatment.

• If the crabgrass plants are fairly well established, you’ll need to apply the herbicide twice. Treat the affected areas again four to seven days after the first application. Make sure the soil is moist before the second application.

• Follow the manufacturer’s instructions about when it’s safe to re-seed grass. Seed new grass in the area as soon as possible to establish a healthy lawn crabgrass can’t break through.

• If you use a post-emergent herbicide during the summer, care for your lawn according to the lawn maintenance tips above.

• If the majority of your lawn is crabgrass, it may be best not to remove it during the summer. Wait and renovate the lawn in the fall.

Killing Crabgrass in Summer -Making Sure It Never Comes Back

Dave Asked: I really need help killing crabgrass. For ten years I had the best fescue lawn in Atlanta, then came our drought. This year we have had a lot of rain and my lawn is FULL of crab grass despite having applied a pre-emergence in February. I have little fescue left. I have a limited budget but want to heavily overseed, but wish not to start from scratch. I will aerate before overseeding, however I’m wondering if the lawn should be slightly plowed for more surface for the seed. Any advice will be deeply appreciated.

Dave
Georgia (See Answer Below)

Answer: Don’t worry, your problem is easily fixable. While killing crabgrass after it has started growing is difficult, it can be done if that is what you decide to do.

The good thing is that crabgrass is an annual plant and dies at the end of each year in the fall. It slows down as temperatures cool and is killed at the first heavy frost. If you can wait, getting rid of crabgrass will be done for you. Crabgrass must start from seed the following year. In your part of the country that would be about mid to late March.

This is important to know: Something fertilizer companies never tell anyone is that frequent, heavy rains will stress preemergence herbicides to the max. Several rains or frequent irrigation won’t hurt, but repeated heavy downpours will and decreases the effectiveness of preemergent herbicides. Since they advertise “crabgrass control”, they don’t want it out that it has several limitations.

Killing Grabgrass with Post-Emergence Herbicides

The best way of killing crabgrass after it has spread is to purchase a product with MSMA as the active ingredient. It is safe for many turfgrasses when used as directed, but is effective in killing crabgrass. You will have to use it soon, before the temperatures dip and the grass hardens off. It is currently prohibited in about 27 states, but is still available for use in GA at the time of this writing. Follow the label directions for mixing and use.

Use a pump chemical sprayer or backpack sprayer to apply the chemical. To eliminate crabgrass, spray your grass so it has a thin film over the grass. Wear rubber boots if you have them. This is the easiest method of killing crabgrass that is growing. It may need a second application. You can apply a “sticker-spreader” into the herbicide solution to help the chemical stick to the grass better. It can be purchased online or other products are also available.

Note: MSMA will harm some desirable grasses and plants, even though most turf species are safe. Read the label carefully to see if you have any varieties that can be harmed and that you have the correct mixing rate for your species.

Facts on Pre-emergent Herbicides

An important thing to know is there are only two types of preemergence herbicides that will last all year with a singe application in early spring. The trade names are “Barricade” and “Dimension”. These are most often sold in professional fertilizers, but may be available to homeowners when purchased from turf supply companies. Most homeowner types of preemergent herbicides, like the type used in Scotts fertilizer for example, are hard pressed to last all year. They are good for three to five months depending on the type used. In southern states where the summers are longer, they will often fail too soon and some crabgrass will get through.

Two remedies for the preemergent problem:

  • Apply the first application of fertilizer with preemergence in early spring BEFORE THE CRABGRASS SEEDS GERMINATE. The herbicide won’t work if applied after the crabgrass starts growing. Then apply a second application of fertilizer and preemergence again a few months later.

    Your summer application should have a lower nitrogen content than the first one, so you don’t apply too much nitrogen when the grass is slowing down because of summer heat. So this means you will have to buy two different bags: one for early spring and a different one for late early summer.

  • The second solution is to have a commercial turf company apply the first application for you using one of the above listed preemergence herbicides guaranteed to last all year.

Now for Overseeding

After killing crabgrass, if it was very thick, it may need to be thinned before seeding. I use an inexpensive non-motorized, pull-behind dethacher. It connects to the back of a riding mower. The dethatcher is about 36 inches wide with tines that drag over the soil and has a steel plate on top for weights. For added weight I use sand bags made from an old car tire tube. (Over the years I have learned that cheap weights work just as well or better as expensive ones) Cut a section of the rubber tube 18 inches long and wire one end closed. Fill the tube with sand or gravel and then wire the other end closed. It can be quite heavy. Two of them will be needed. If they bounce off then tie them on with heavy string or cord. The dethatcher costs about a hundred dollars or so and is sold in many large lawn and garden stores.

In early fall, when the high temperatures are in the low to mid eighties, pull the dethatcher over the lawn several times in different directions. It will pull up a lot of old grass and make a big mess. The purpose is to remove as much dead crabgrass as possible. Remove the debris before spreading seed.

Buy a quality “turf-type” tall fescue seed. Try to purchase seed from a good source, such as a landscaper or turf supply company. They will have the best seed used by commercial companies. Don’t buy budget seed or you will probably not be happy with it.

You can apply a starter fertilizer in the fall at the time of overseeding or up to a few weeks after seeding. However, DO NOT apply a preemergent in the summer or fall if you plan to overseed that year or it will keep you seed from germinating. Use proper watering techniques and you should be fine.

I hope this helps. Remember, killing crabgrass can be challenging after it has started growing. “Killing Crabgrass” is not necessary if you use a good preemergent in early spring. Good luck and let me know how it goes.

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Crabgrass starts to germinate when soil temperatures reach 55 degrees. If you have crabgrass in your lawn, learn how to get rid of it from the experts at Jonathan Green.

Who Is Jonathan Green?

Our ancestor and founder, Jonathan Green, set out to grow turf grass in England in 1881 to beautify lawn bowling surfaces in the north of the country. He succeeded in developing turf grass varieties with uniform leaf texture, dark-green color and superior wear tolerance, and went on to construct lush bowling greens in towns throughout northern England. We continue to build on the foundation he laid six generations ago.

Today, Jonathan Green supplies genetically superior grass seed, soil enhancers, fertilizer, and organic lawn and garden products to professional customers, such as sod growers and independent retailers, throughout the Northeast, Mid-Atlantic and Midwestern United States.

Prevent Crabgrass with a Healthy Lawn

Crabgrass is a coarse, light green, unattractive warm-season annual weed and a very aggressive species that steals valuable moisture and nutrients from the soil and competes with desirable lawn grasses. Native to Africa, it was introduced to North America by European settlers in the 1800’s as an animal feed.

Crabgrass is relentlessly prolific and can produce more than 150,000 seeds per plant. The seeds begin to germinate when soil temperatures reach about 50-55 degrees Fahrenheit, and the plants really spread in lawns in July and August.

Although the plants will die with the first frost (usually October), they will produce seed heads during late summer to ensure a new crop of crabgrass plants the following year. If the cycle is not stopped, the seeds will lay dormant in the soil until spring, when they will be ready to jump into action again.

Crabgrass and other lawn weeds are symptomatic of a weakened turf, not the cause of it, so the best defense against crabgrass and other weeds is a thick, healthy lawn.

Interrupt the germination of existing crabgrass seeds in the spring, ideally in April or May. You can accomplish this by introducing grass seed to thin areas of your lawn and following our New American Lawn Plan.

Apply Jonathan Green Crabgrass Preventer plus New Seeding Lawn Fertilizer on the same day you sow grass seed. This pre-emergent herbicide prevents crabgrass and grassy weeds from germinating without injuring new grass seedlings. It contains 30% slow-release nitrogen to feed the new seedlings gently and longer.

If you don’t plan to seed but want to fertilize your lawn and prevent crabgrass, consider Jonathan Green Organic Weed Preventer plus Lawn Food. It stops crabgrass, dandelions and weeds before they sprout and includes an organic fertilizer named corn gluten that greens up the lawn quickly. It also releases organic proteins into the soil to encourage root development. Apply it in early spring, but do not sow grass seed for at least 60 and up to 90 days..

Control Existing Crabgrass

If it’s mid-summer and the crabgrass is already growing, you can wait it out and attack it in a timely manner next season or treat it with an herbicide specifically labeled for crabgrass control.

Jonathan Green Green-Up Lawn Food with Crabgrass Preventer contains the newest technology with Dimension® Crabgrass Control Herbicide. This product controls crabgrass before and after it germinates (up to the 3-leaf stage of growth; crabgrass is a 7-leaf plant when mature) and can be applied up to four weeks later than other crabgrass preventers. It will feed your lawn gently for up to 8 weeks, however, do not seed with this product.

For more help with how to get rid of crabgrass in your lawn, visit Jonathan Green online or visit your nearest independent retail store for advice.

How to Get Rid of Crabgrass in Texas

Everyone wants an attractive lawn, but it’s not the reality for most households and commercial properties. During the peak summer months when your grass is on the verge of burnout, you might notice that the crabgrass thrives and even chokes out the rest of your lawn. How do you get rid of crabgrass?

Knowing how to kill crabgrass will help you keep your lawn looking as green as possible. Follow these steps to rid your yard of crabgrass yourself, or to help you select a lawn care service.

What Is Crabgrass?

This renegade weedy grass that seems to have a mind of its own belongs to the species Digitaria. The chances are that if crabgrass has invaded your lawn, it’s either large or smooth crabgrass. While it is most often found in lawns that lack the proper irrigation or fertilization, crabgrass can still appear in well-tended lawns.

You can deal with the problem yourself, or leave it to the experts by reaching out to Zodega TIS’s Houston residential lawn care. We know how to get rid of crabgrass in your lawn.

Herbicides for Killing Crabgrass

Knowing what stage your crabgrass is in will determine if you try a pre-emergent or post-emergent herbicide. Pre-emergent herbicides for killing crabgrass will kill seedlings as they germinate. A pre-emergent herbicide is typically best when mixed with lawn fertilizer.

Post-emergent herbicides for killing crabgrass control growth after germination. They are typically applied as a spray directly on the troubled grass after it has sprouted.

How to Kill Crab Grass in Different Grass Species

Your grass type will determine the method you or your lawn service will use to get rid of crabgrass.

How to Get Rid of Crabgrass in St. Augustine Grass

A turfgrass, St. Augustine is a popular choice for the Southern U.S. due to its ability to thrive in subtropical and tropical climates. While St. Augustine grass usually crowds out weeds, sometimes crabgrass pops up.

The first step of figuring out how to get rid of crabgrass in St. Augustine grass is to choose a weed killer that is compatible with this grass type.

You might think that killing crabgrass in summer is ideal because that’s when it seems to overtake your lawn, but it is best to treat the area in the spring when you begin watering your lawn more. As your watering promotes growth, counteract that with a crabgrass-killing pesticide.

If you notice crabgrass in the summer, make sure you treat your lawn with a compatible post-emergent herbicide for crabgrass.

Getting Rid of Crabgrass in Bermuda Grass

Anyone who’s ever teed off on a golf course has probably seen Bermuda grass. This warm-weather grass is even known as the “South’s Grass” for its popularity in the Southern U.S.

Getting rid of crabgrass in Bermuda grass takes constant attention. Bermuda grass tends to be a fast-growing grass, so if crabgrass starts popping up, it’s best to attack the problem immediately and aggressively. Knowing how to get rid of crabgrass in the summer is especially important, as the summer months are when crabgrass seems to grow the most in Bermuda grass.

The method follows the same basic format you would use for St. Augustine grass: pull the bulk of the weeds, treat with an herbicide that is compatible with your grass, re-seed the bare spots and water the lawn deeply.

Make sure you treat your lawn with pre-emergent herbicides for killing crabgrass the following Spring.

How to Kill Crabgrass in Zoysia Grass

Touted as a low-maintenance, hardy, and slow-growing grass, Zoysia grass can still become invaded with crabgrass. Low-maintenance can allow crabgrass to go unnoticed until the problem has taken root (sorry).

The best way to kill crabgrass in Zoysia grass is to prevent crabgrass growth in the first place by not cutting your lawn too short. Taller grass (about 2.5 to 3 inches) will shade your lawn’s undergrowth and inhibit crabgrass growth. Remove clumps of crabgrass and water the area enough to loosen the crabgrass roots. Next, follow with a compatible herbicide.

If you’re battling Texas crabgrass, determining the best way to get rid of crabgrass can seem overwhelming. Zodega TIS is here to help with your residential or commercial lawn care in Houston.

Contact us today for a quote on how to get rid of crabgrass in Texas.

Get ’em before they sprout!

Watch this video to learn about the tried-and-true secrets to getting rid of crabgrass ASAP:

Crabgrass Weed Killer

The best weapon you have to know how to kill crabgrass is pre-emergence herbicide (also called crabgrass preventer). You apply this product in the spring before the crabgrass seed sprouts. This granular herbicide works by creating a chemical barrier at the surface of the soil. As the seeds begin germination, they take in the herbicide and die.

If you’ve had a particularly bad crabgrass problem, you’re not done for the season. Chances are that the crabgrass will germinate and spring up later in the summer. Pre-emergence herbicides have a life of about 50 days (check the label; product life spans vary). Once that chemical barrier breaks down, dormant crabgrass seeds, which can remain viable for years, may germinate into seedlings. Or if your yard butts up against property that has a thriving crabgrass crop, you can bet that thousands of seeds will blow into your lawn, just when your herbicide is calling it quits.

You don’t need to reapply the pre-emergence herbicide to your whole yard to learn how to kill crabgrass, but hit areas again where crabgrass thrives, like right next to driveways and walking paths. Because they absorb heat, the soil around them gets warmer and encourages the growth of crabgrass.

If weeds are making their way into your flower beds, here’s how to get rid of weeds in flower beds.

Crabgrass Control in Lawns for Homeowners in the Northern US

This publication is intended for homeowners and other non-professionals with lawns of cool-season turfgrass species such as perennial ryegrass (Lolium perenne), tall fescue (Schedonorus arundinaceus), fine fescues (Festuca spp.), or bluegrass (Poa spp.). These turfgrass species are commonly found in New Jersey and much of the northern United States. If you are a professional turfgrass manager see FS1309, Crabgrass and Goosegrass Identification and Control in Cool-Season Turfgrass for Professionals.

Introduction and Identification

Crabgrass

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Figure 1. Crabgrass in a lawn. Notice the coarse texture and light green color of crabgrass compared to the surrounding cool-season turfgrass.

Crabgrass (Digitaria spp.) is a true annual in the northeastern United States (Figure 1). Seeds germinate in the spring and seedlings grow rapidly throughout the summer as a warm-season (C4) plant. At maturity in late summer, plants produce seed before dying at the first frost in autumn. Each plant can produce thousands of seeds that remain viable in the soil for several years, making this annual weed a perennial problem.

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Figure 2. Smooth crabgrass and large crabgrass. Notice the hairs along the stem and leaves of large crabgrass, while the smooth crabgrass has a purple stem and is hairless.

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Figure 3. Smooth crabgrass seedhead.

Smooth and large crabgrass (Digitaria ischaemum and D. sanguinalis, respectively) are the most common crabgrass species found in the northeastern United States (Figure 2). Crabgrass has a rolled stem (rolled vernation) and lime green, coarse-textured leaves. It typically has a prostrate growth habit, spreading out along the ground. Crabgrass seedheads appear finger-like with spikes (racemes) arising from different points at the top of the stem (Figure 3). The leaves and leaf sheaths of large crabgrass are typically covered in dense hairs while those of smooth crabgrass are hairless (glabrous) and purple at the base. In the northeastern and mid-Atlantic regions, smooth crabgrass is more prevalent than large crabgrass.

Other Summer Annuals

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Figure 4. Foxtails with seedheads.

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Figure 5. Goosegrass plant.

Crabgrass is the most common summer annual grassy weed of cool-season home lawns, but other summer annuals such as foxtail (Setaria spp.) and goosegrass (Eleusine indica) can be found occasionally. Foxtails are most easily identified in late summer once plants produce a seedhead that contains bristly awns (Figure 4). Goosegrass is another summer annual that, although not common in home lawns, is prevalent in parks and sports fields with highly trafficked, compacted soil. Goosegrass is most easily identified by a whitish, flattened stem (folded vernation) and prostrate growth habit (Figure 5). The seeds are arranged in a herringbone pattern on the seedhead spike.

Controlling Crabgrass and other Summer Annual Weeds

A dense stand of turfgrass is the most effective way to prevent summer annual weeds. Supply adequate nitrogen fertility (often 2 to 3 fertilizer applications per year in New Jersey), other nutrients, and lime as determined by a soil test to maintain a dense canopy of desirable turfgrass. Apply nitrogen fertilizer in early autumn and, if needed, in the spring when cool-season grasses are more competitive than these warm-season weeds. Applying nitrogen fertilizer from mid-June through mid-August will promote the growth of crabgrass and other summer annual weeds more than the desirable turfgrass.

Research shows that mowing at the highest height recommended for your particular turfgrass species can significantly reduce crabgrass infestations compared to a low mowing height. Combining a higher height of cut with proper fertilization will create a dense turfgrass canopy that will shade the soil and make it more difficult for weed seedlings to survive.

If an irrigation system is available, irrigate deep and infrequently (once or twice per week), and only when the desirable turfgrass exhibits initial signs of drought stress. In New Jersey, grasses mowed at > 2.5 inches rarely need supplemental irrigation in the springtime. Frequent irrigation is not desirable as it keeps the surface of the soil moist and encourages weed seedlings to survive.

Where severe crabgrass infestations are present in summer, a late summer or early autumn seeding of desirable cool-season turfgrass is a valuable management practice. Seeding at this time will fill the voids created when these annual weeds die and result in a dense turfgrass canopy that prevents weed seedling survival the following spring. For more information on turfgrass fertilization and seeding see FS108, Renovating Your Lawn and E327, Best Management Practices for Nutrient Management of Turf in New Jersey.

Mechanical Removal

Minor infestations common along sidewalks or other areas where the lawn is thin can often be managed by hand removal rather than herbicides. It is important to remove plants before seed is produced. Crabgrass and foxtails have a fibrous root system and the plant crowns (basal growing point) can be easily removed by hand or an upright weeding tool when the plants are small. Plants will not regrow if the crown of plants is removed. As crabgrass matures it can root at nodes on stems growing along the ground. Goosegrass can be removed mechanically when it is immature, but as the plant matures and the central taproot develops it becomes more difficult to remove. Since seeds can germinate through the summer months, hand removal several times during this period may be necessary.

Herbicide Options

In areas with a history of infestations that cannot be managed with cultural practices and mechanical removal alone, herbicides are an effective and economical option when applied at the proper time and rate. These products are safe when used according to directions. It is especially important to sweep the product off of sidewalks, roads, and other hardscapes to prevent runoff.

Pre-Emergent Herbicides

Especially in areas with a history of moderate to severe infestations, pre-emergence herbicides are more economical and effective than post-emergence herbicides. Pre-emergence herbicides should be applied and watered into the soil before crabgrass germinates in the spring. Most pre-emergent herbicides will not control crabgrass after it germinates. These herbicides do not control other summer annual weeds such as goosegrass or foxtail as well as crabgrass.

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Figure 6. A forsythia shrub in full bloom and closer view of the flowering branches (inset).

Crabgrass typically germinates mid to late April in central and northern New Jersey and early to mid-April in southern parts of the state. Forsythia is an excellent phenological indicator for crabgrass germination (Figure 6). When forsythia is in full bloom, crabgrass pre-emergent herbicides should be applied as soon as possible. Foxtails typically germinates 3 to 4 weeks after crabgrass.

Pre-emergent herbicides should be applied to well-established, mature turfgrass. Do not apply any of the pre-emergence herbicides listed below if you plan to seed several weeks after the application, as these herbicides will kill turfgrass seed. See the product label for more information on use before or after seeding, even if seeding was conducted the previous autumn. Products listed below are safe on most cool-season turfgrasses, but always refer to the label for turfgrass tolerance information especially where fine fescue (Festuca spp.) is desired.

Most products are equally effective if applied uniformly at the proper rate. Poor application uniformity and/or using too little product are common causes of pre-emergence herbicide failure. For example, if the product bag indicates that the product covers a 5,000 square foot lawn and you use it to cover 7,500 feet, do not expect the product to provide excellent crabgrass control. Immediate irrigation or rainfall after application is not usually necessary (unless crabgrass germination is imminent), but is typically recommended within 2 to 7 days after application. Carefully follow the product instructions for best results.

Effective pre-emergent herbicides (often listed as crabgrass preventers) are listed below based on their active ingredient. Most pre-emergent herbicides are available as a granular (with or without fertilizer) that can be applied through a rotary or drop spreader. Products listed below are commonly found in the garden center of both small and large retail stores. The list below is not comprehensive but represents active ingredients that are most effective for crabgrass control. Brand names change frequently. Read the fine print on the product label to find the active ingredient which is the most important indicator of product effectiveness.

Active Ingredient Brand Names Notes
pendimethalin Scotts Step 1 or Halts Crabgrass Preventer, Vigoro Crabgrass Preventer In areas with a history of severe crabgrass infestations or sandy soils, consider applying once in the spring before crabgrass germinates and again in early June.
dithiopyr Dimension, Bonide Crabgrass and Weed Preventer, Greenview, Preen Lawn Crabgrass Control, Jonathan Green Green-Up with Crabgrass Preventer, Scotts Snap Pac Crabgrass Preventer, Spectracide Weed Stop for Lawns The active ingredient dithiopyr is unique in that it can control crabgrass even if applied up to 4 weeks after germination. See the label for more information on the application rate especially if applying after crabgrass germination. Delaying the application to take advantage of this early post-emergence control will extend the crabgrass control further into the summer. Utilizing this delayed strategy may be especially important in sandy soils. Dithiopyr does not provide early post-emergence control of other weeds. Many products that contain dithiopyr can also be used in ornamental beds.
prodiamine Barricade A single application typically provides season long crabgrass control. In areas with a history of severe crabgrass infestations or sandy soils, consider applying once in the spring before crabgrass germinates and again in early June. In lawns that are predominately fine fescue, over-application can cause injury. Read the label carefully before applying in fine fescue.
mesotrione Scotts Turf Builder Starter Food for New Grass Plus Weed Preventer Mesotrione has less residual efficacy than other pre-emergence herbicides but can be safely applied at and shortly after seeding many cool-season turfgrass species. When applied at seeding it will provide pre-emergence crabgrass control up to four weeks. This product is especially useful for weed control if you are seeding in the springtime. Mesotrione will often cause new seedlings to appear bleached, but they typically recover within 2 weeks. Be careful not to over-apply, especially to seed mixtures that are predominantly fine fescue. Do not apply to zoysiagrass (Zoysia spp.).
siduron Tupersan, Jonathan Green Crabgrass Preventer Plus New Seeding Lawn Fertilizer, others Similar to mesotrione, siduron has less residual efficacy than other pre-emergence herbicides but can be safely applied at and shortly after seeding many cool-season turfgrass species. Siduron is generally less effective than mesotrione but will provide pre-emergence crabgrass control up to four weeks. Use at the highest recommended rate for best crabgrass control. Siduron is especially useful for weed control if you are seeding in the springtime.

Post-Emergence Herbicides

In areas with a history of moderate to severe infestations, it is more economical and effective to rely primarily on pre-emergence herbicides and use post-emergence herbicides where plants “escape” the pre-emergence herbicide. Relying exclusively on post-emergence herbicides is recommended only if pre-emergence herbicides are not an option or in areas with a history of very minor crabgrass infestations.

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Figure 7. Two smooth crabgrass plants with many tillers as commonly observed in mid-summer.

Post-emergence herbicide effectiveness is highly dependent on crabgrass growth stage. Small plants commonly found before early July are much easier to control than plants that have multiple stems (tillers). Crabgrass typically begins to tiller and mature rapidly beginning in mid to late June (Figure 7). From early July through mid-August, effective post-emergence control will often require multiple applications on a 2- to 3-week interval. Post-emergence herbicide efficacy usually improves again in late August once plants mature and temperatures cool. If you did not apply a pre-emergence herbicide, it is a good idea to scout the lawn for small crabgrass plants in mid-June and apply an herbicide if necessary.

Post-emergence herbicides are most often applied as a spray either through a hose-end or pump-type sprayer. The herbicide must be absorbed by the plant leaves to kill the weed. Apply these herbicides under ideal growing conditions. If the lawn is under drought or heat stress, herbicides will be less effective and may injure the turfgrass.

Herbicides listed below are safe to most cool-season turfgrass species if applied properly. Always check the label to make sure the product is safe for use on the grass species in your lawn.

Active Ingredient Brand Names Notes
fenoxaprop-p-ethyl Bioadvanced (formerly Bayer Advanced) Crabgrass Killer for Lawns This herbicide may cause temporary stunting or yellowing to Kentucky bluegrass. Do not apply herbicides such as 2,4-D, MCPA, or MCPP for broadleaf weed control within 5 days before or 21 days after a fenoxaprop application or it will not control crabgrass. Fenoxaprop will not provide good weed control if the plants are drought stressed. Fenoxaprop controls most summer annual grassy weeds including crabgrass.
quinclorac Bonide Weed Beater Plus Crabgrass Control, Ortho Weed-B-Gon Plus Crabgrass Control, RoundUp for Lawns 3, Spectracide Weed Stop for Lawns Plus Crabgrass Killer Quinclorac also provides excellent control of some broadleaf weeds such as white clover (Trifolium repens). If your lawn is predominantly fine fescue this product may not be safe. Read the product label carefully before applying. Quinclorac controls many summer annual grassy weeds, but does not control goosegrass.

Organic Herbicides

Organic herbicides are not as effective or consistent as synthetic herbicides. In an organic system, utilizing proper cultural practices is of the utmost importance. This includes mowing at the highest recommended height (typically 3 to 5 inches) for the turfgrass species in your lawn as well as proper fertilization, irrigation, and seeding discussed earlier in this publication.

Pre-Emergence Herbicides

Products that contains corn gluten meal or corn gluten hydrolysate rarely provide acceptable control of severe crabgrass infestations. It is worth noting that corn gluten meal contains a substantial amount of nitrogen fertilizer, which can increase turfgrass density and reduce crabgrass infestations. There are other products sold for crabgrass control that contain soybean or other horticultural oils. We have not observed crabgrass control from these products in our research.

Organic post-emergence herbicides are typically non-selective and may provide control of small crabgrass plants, but these products will also injure or kill surrounding turfgrass that is contacted by the herbicide. Effectiveness of most organic herbicides is highly dependent on environmental conditions. Better control occurs as relative humidity and air temperature increase.

Conclusions

Effective crabgrass control requires a healthy and dense lawn. In lawns with a history of moderate to severe crabgrass infestations, proper herbicide selection and application is also important. Knowing the weed history of a particular site can help you develop an economical and effective strategy. For example, on a site with a history of moderate to severe infestations, a pre-emergence herbicide is important. In this situation it is also likely that spot treatment with a post-emergence herbicide will be necessary, especially if the turfgrass canopy thins in mid-summer due to biotic or abiotic stress. In sites with a history of minor infestations and good turfgrass cover you can expect pre-emergence herbicides to be very effective or choose to rely exclusively on mechanical removal and/or spot treatment with post-emergence herbicides.

Always read the label very carefully before applying any product to your lawn. Pay careful attention to which turfgrass species the product can be applied and how to apply the product for maximum effectiveness and safety around humans and pets.

Photo credits: Matt Elmore (Figure 1, 2, and 5–7), Eric Reasor (Figure 3), Max Pixel (Figure 4).

Mention or display of a trademark, proprietary product, or firm in text or figures does not constitute an endorsement by Rutgers Cooperative Extension and does not imply approval to the exclusion of other suitable products or firms.

August 2019

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