Managing Weeds Archives - Organic Lawns by Lunseth

Managing Crabgrass and Other Weeds

Posted on July 16, 2025 | by Organic Lawns by Lunseth

The Twin Cities’ excessive rainfall this year has been great for our lawns. Weeds already compete with your turfgrass during the hot months of the summer, and the spring rains gave them a jumpstart. This month we’ll help you identify the most common weeds you’re seeing and provide natural best practices to control them.

Crabgrass

The University of Minnesota Extension Service describes crabgrass as a prolific weed that survives harsh conditions through its abundant tillering (creation of shoots other than the main shoot) and seed production. One crabgrass plant can produce up to 150,000 seeds in a single season. Crabgrass seed germination occurs in the spring, when soil has an average temperature high enough to support growth. These seeds produce even more crabgrass plants over the summer.

There are steps you can take to control crabgrass:

The best way to control crabgrass is in the early spring, applying a pre-emergent herbicide – Corn Gluten – before the soil temperatures reach approximately 55°F.
Keeping your mowing height to a minimum of 3 inches helps decrease crabgrass seed germination.
One of the best strategies to combat crabgrass, and other weeds in general, is to maintain a healthy lawn.

Chickweed

Chickweed is challenging because of its ability to grow in a variety of conditions. PennState Extension says it’s found in both high and low maintenance turf, in sunny and shaded areas, and in many different soil types. Common chickweed stems grow close to the ground then turn slightly upright, producing leaves and flowers. It’s generally classified as a winter annual. It produces shallow root systems and long, branching stems that grow prostrate along the soil surface. Seeds can germinate during spring, summer, and fall. Common chickweed produces one or two generations per year.

Common chickweed can be controlled with three to four applications of liquid iron each year. However, mouse-ear chickweed can tolerate iron applications due to the trichomes on the leaves. Improving turf density through non-chemical fertilization, regular mowing, and use of turfgrasses well-adapted to site conditions also helps. The University of California Department of Agriculture and Natural Resources provides these guidelines for natural control:

Nonchemical controls include hand weeding, cultivation, and adding mulch to garden beds.
Chickweed should be controlled before it flowers. This can be difficult due to the short period between germination and flower production. However, regular monitoring and removal of plants from the site will prevent seeds from developing and accumulating in the soil (seed bank).
It’s important not only to remove the plants from the ground but also to remove them from the site. Common chickweed can re-root from stem nodes in moist areas.

Chances are, you see other weeds in your lawn. Some of the most common are:

Dandelions
Dutch white clover
Ground ivy (creeping Charlie)
Quackgrass
Wild violet (common blue violet)

Following the management guidelines we provided can help manage weeds. Contact the experts at Organic Lawns by LUNSETH to create the best organic weed control program for your yard.

Organic Methods for Controlling Crabgrass in Your Lawn

Posted on August 9, 2024 | by Organic Lawns by Lunseth

Crabgrass is a common warm-season annual that’s a member of the grass family. The problem is that most people don’t think of it as a grass and want it gone! There are two primary species of crabgrass: the large or hairy crabgrass (Digitaria sanguinalis) and small or smooth crabgrass (Digitaria ischaemum). Chances are you have one or both.

Why Does Crabgrass Thrive?

There’s a reason you probably can’t keep up with crabgrass spreading in your yard. It’s one of the most persistent weeds around and a prolific seed spreader. The University of Minnesota Extension Service explains that crabgrass survives harsh conditions through its abundant tillering (creation of shoots other than the main shoot) and seed production. Its structure allows up to 150,000 seeds per plant to be produced in a single season. It’s no wonder it’s hard to keep it under control.

The UMASS Extension Center states that crabgrass seeds germinate best from early spring to late summer. And it continues to grow until midsummer when days become shorter. This is when its growth slows and the plants enter the reproductive stage.

Controlling Crabgrass

Crabgrass is generally controlled with preemergence herbicides that are applied before the seeds germinate. LUNSETH controls crabgrass with an early and heavy application of corn gluten meal, aiming to get it down before the soil temperatures reach 55°F. Unfortunately, we have no organic post-emergent solutions for crabgrass. Synthetic herbicides, such as Quinclorac, can kill it and are best applied during the first tillering stage.

It’s important to remember that controlling crabgrass isn’t a quick fix. UMASS Extension warns that crabgrass cannot be controlled in one growing season because of the great number of viable seeds that can accumulate in the soil from years of infestation. It takes several years of controlling crabgrass seed production to reduce the viable seed supply.

The good news is that good cultural practices can result in a healthier, denser turf, which in turn increases its overall competitive nature and decreases the severity of crabgrass infestations. Some crabgrass infestations can be significantly reduced with the use of appropriate and well-timed cultural practices.

Conclusion

The experts at Organic Lawns by LUNSETH help our clients control crabgrass organically by emphasizing soil health, proper maintenance practices, and natural remedies. By integrating these methods into your lawn care routine, you can gradually reduce crabgrass while promoting a vibrant and resilient grassy landscape. Embracing organic solutions not only protects the environment but also contributes to a healthier and more sustainable outdoor space for you and your family to enjoy.

Organic Methods for Controlling Clover in Your Lawn

Posted on July 15, 2024 | by Organic Lawns by Lunseth

Clover, particularly white clover (Trifolium repens), is a hardy perennial often found in lawns because it thrives in almost any soil condition and can withstand foot traffic. Some homeowners embrace it because they appreciate its drought resistance and provides food for our pollinators. A field of clover can be beautiful for some, but not for everyone.

Organic Control Methods
Fortunately, there are several organic methods to control clover in your lawn, promoting a healthy and lush carpet of grass without compromising environmental integrity:

Manual Removal: Hand-pulling clover can be effective for smaller patches or isolated areas. Make sure you remove the entire plant, including its roots, to prevent regrowth.
Mowing Height: Maintaining taller grass height (around 3 inches) shades the soil, making it harder for clover seeds to germinate and establish.
A Healthy Lawn: A vigorous grassy lawn is achieved through proper watering and fertilization.
Applying a solution of vinegar (with an acetic acid concentration of at least 10%) directly to clover patches can effectively kill the clover. Make sure to avoid getting any on your grass because it can damage it too.
Multiple applications of chelated iron can suppress some broadleaf weeds, including clover.
Patience and Persistence: Organic methods, like most rewarding things in life. Require time and consistent effort. Regular monitoring and maintenance will help prevent clover from taking over again.

Conclusion
The experts at Organic Lawns by LUNSETH help our clients control clover organically by emphasizing soil health, proper maintenance practices, and natural remedies. We always have a tolerance for 5-10% of weeds within a lawn, as our approach cannot control all of them. Many weeds that we cannot control add good diversity to your lawn and support pollinators. By integrating these methods into your lawn care routine, you can gradually reduce clover while promoting a vibrant and resilient grassy landscape. Embracing organic solutions not only protects the environment but also contributes to a healthier and more sustainable outdoor space for you and your family to enjoy.

Handle Spring Weeds Now or Pay the Price Later

Posted on April 19, 2024 | by Organic Lawns by Lunseth

Weeds have been resting all winter and can’t wait to shoot through and start growing. You probably already know that when they do, they start growing – well – like weeds! This often happens so fast that by the time you try to get rid of them, they’ve already taken over. Thin or bare soil areas combined with sunlight and warm soil temperatures create a perfect opportunity for germination of many of our annual weeds.

These weed seeds aren’t just perennials that lay dormant over the winter. They can be blown in by the wind or be carried in by our bird friends. Early spring is the time to start looking for these intruders and taking steps to reduce their spread. Below are some of the most common weeds we see in Minnesota. Along with our tips for getting them under control.

Crabgrass

Crabgrass is a summer annual that germinates inthe early spring and dies in the fall. The seeds germinate when soil

temperatures reach about 55°F. Crabgrass can often be found along sidewalks and driveways because the proximity to asphalt and concrete allows the soil to heat up much faster. Areas of the lawn that are south-facing and have full exposure to the sun may also see more crabgrass than other areas. It is a warm-season species that easily out-competes the cool-season grasses during the high-temperature stress periods of midsummer. It is easily recognized by its distinctive seedhead, which looks like protruding fingers, thus its Latin name Digitaria (digits, or fingers). The seedhead branches from multiple locations on the seed stalk. This grass has a rolled vernation, and smooth crabgrass can be purple near the base.

Crabgrass is generally controlled with preemergence herbicides that are applied before the seeds germinate. Organically, you can control crabgrass with an early and heavy application of corn gluten meal, aiming to get it down before the soil temperatures reach 55°F (3-years to achieve the best suppression). There is no organic post-emergent control for crabgrass, but synthetic herbicides containing Quinclorac can kill it.

Prostrate Knotweed

Prostrate knotweed looks a little like prostrate spurge, but it is easy to distinguish the two. The knotweed has symmetrical leaves that are arranged in an alternating pattern along the length of its runner. It also lacks the milky sap that is typical of the spurge. The knotweed germinates very early in the spring and can sometimes be found peeking through as the snow melts. It was identified at its earliest this year at the Turfgrass Research Center, in February! It looks a little like grass when it first emerges, and is sometimes mistaken for emerging crabgrass. The knotweed will usually show up six to eight weeks or even more, before crabgrass.

Prostrate knotweed can be controlled with pre-emergent weed control, but if it is applied early enough to control this species, it will lose its effectiveness before the later germinating species, such as goosegrass. Multiple applications of a synthetic post-emergent herbicide can have little effect. Knotweed is a sign of soil compaction, and it is usually found in compacted areas along sidewalks or in other heavily trafficked areas. Relieving the compaction through aeration and following other sound management techniques to produce a healthy lawn are generally the best way to handle knotweed.

Oxalis

Yellow woodsorrel (better known as oxalis and shamrock), is an annual or a weak perennial in northern regions of the United States. It is easily recognized by its three-part leaf with distinct heart-shaped leaflets and its yellow flowers with five petals. It germinates in midsummer and often becomes a problem in August.

This species can be controlled with pre-emergent herbicides, but its late germination makes it difficult to control in this manner. Selective post-emergent herbicides can control it, but these applications need to be applied carefully to prevent damage to desirable plants during the warmer part of the summer. Three to four applications of chelated iron would be needed to control it. This weed is easy to hand pull, as it does not resprout from roots left behind. Proper irrigation, fertilization, and other sound management steps that keep the lawn healthy provide the best means of preventing this weed from becoming a problem.

Black Medic

Black medic is considered an annual clover, even though it is not part of the clover

genus. It has teardrop-shaped leaves clustered in groups of three, similar to clover. The flowers are small, round, and yellow. Black medic is a species that is an indication that the lawn grasses are not as competitive as they could be with proper management. It often shows up on hillsides, where water does not readily penetrate the soil, or in compacted areas.

The adoption of sound lawn management techniques, along with pre-emergent or post-emergent weed control, will provide satisfactory control of this species. Hand weeding this weed is not difficult, since it grows from a central location. One application of chelated iron will kill this weed.

Prostrate Spurge

Prostrate spurge, as its name would indicate, grows in a prostrate manner along the surface of the ground. It has leaves that are paired opposite one another along the length of its runner. The individual leaves are asymmetrical, meaning that they are not the same on both sides of the midrib. Some varieties will have a purple/red spot on the middle of the leaf. If the stem is broken, a drop of milky sap will form at the end of the broken stem. This sap can irritate the skin, so wear gloves when hand pulling this weed. Spurge and knotweed can be mistaken for each other, but knotweed does not produce a milky sap when the stem is broken and its leaves grow in an alternating pattern. Spurge generally germinates later than goosegrass, which germinates later than crabgrass.

These three species are a difficult combination to control with pre-emergent herbicides. If the herbicide is targeting crabgrass germination, it will have lost its effectiveness before the spurge germinates. Spurge can be controlled with a number of post-emergent herbicides, such as 2,4-D and MCPP, but it is risky to use these chemicals in midseason because of damage to trees and shrubs. Spurge generally germinates into open areas in the lawn, and the best way to control it is with proper cultural techniques that prevent it from becoming established.

Homeowner holding dandelion in front of green lawn.

Liquid Iron for Lawns

Posted on May 31, 2022 | by Organic Lawns by Lunseth

Now that you’re spending more time outdoors cutting and maintaining your lawn, you may be wondering how your neighbor always seems to achieve that vibrant green color year after year. And why is it they never seem to have any dandelions or moss growing in their yard but you do?

The answer might be simply that they’re treating their grass with liquid iron.

What’s Liquid Iron?

Good question! Liquid iron for lawns is an iron-based weed control that’s bound to a chelating agent, which disguises the iron as an amino acid. As a result, broadleaf weeds—such as clover, dandelions, and plantains—think it’s food. And while stubborn weeds end up absorbing too much of the iron, your grass takes in just the right amount, stopping when it’s had enough.

What happens next? Your weeds will end up dying off while your lawn receives the valuable micronutrients it needs to give you that healthy green color you’re after.

Is Liquid Iron Good for Lawns?

When applied correctly, liquid iron can work wonders for your grass. In addition to killing off weeds, without the use of harmful chemicals, it helps mitigate iron deficiencies in your grass, resulting in healthier and greener lawns.

Other Benefits of Chelated Liquid Iron for Lawns

Liquid iron is a non-toxic solution to weed and moss control
Through the process of iron oxidation, weeds quickly dry up, turn black, shrivel, and die within hours.
Results can be seen within hours of first application

When to Apply Liquid Iron to Lawn

At Organic Lawns by LUNSETH, we recommend applying liquid iron around the time dandelions, and other common weeds, are starting to bloom. You may also be able to apply liquid iron in the fall, when the temperature is cool, and there is ample moisture.

Homeowners often ask us how often to apply liquid iron to lawns. For best results, you may need to repeat the application in 3 to 4 weeks after the first spray.

To address weeds, such as creeping charlie, clover, plantains, and thistle, 3-4 applications may be necessary; however, you don’t want to apply this treatment to the same area more than 4 times a year max.

Liquid iron may take up to 1 hour to dry, so remember to keep your kids and pets off the lawn until your grass is completely dry.

Note: Your lawn may experience some discoloration after the first application. However, unlike weeds, your grass will rebound.

How Do I Apply Liquid Iron?

Moderately spray the liquid iron in your turf while being mindful of desirable plants around the area and other non-target objects.

If you or your plants do come into contact with the spray, be sure to rinse off with water, as it can be a mild skin irritant.

A few words of caution:

Correct application of liquid iron for grass is key to its success. Therefore, be sure you follow these essential rules before you get started:

If grass has become stressed due to hot temperatures or a drought, avoid application.
Don’t apply if rainfall is expected within 3 hours of the time of application.
Don’t apply if the temperature is expected to exceed 85° F.
Always read instructions carefully before straying
Call an expert when in doubt!

Need Organic Help with Your Lawn Care?

As a homeowner, you already have enough on your plate. Why not get professional support for your lawn with some help from Organic Lawns by LUNSETH. We offer professional organic lawn care services, including chelated liquid iron applications!

We’re always here to answer your questions and offer up our best organic solutions. Contact us with questions or concerns at any time.

Here’s to a beautiful summer and a lusciously green yard ahead!

Why Use Corn Gluten Meal for Lawns?

Posted on April 1, 2022 | by Organic Lawns by Lunseth

Looking for an organic alternative to synthetic chemical herbicides? Meet Corn Gluten Meal (CGM), an effective pre-emergent weed preventer used for controlling crabgrass and other common weeds in your lawn.

Organic Corn Gluten Meal 101

Before we discuss the benefits of applying corn gluten to your lawn, let’s first define what it is and how it works:

CGM is a natural by-product of the corn wet milling process. It contains essential nutrients, such as proteins, to inhibit root growth during seed germination. It is also a natural source of nitrogen (9-0-0) to help keep your lawn green and lush.

The key to CGM is applying it to your lawn before (not after) the germination process begins and weeds have already taken root.

Note that as this is an organic lawn solution, it will take some time to continue to prevent the seed from germinating naturally. With each year of application, the percentage of how much it prevents will increase (e.g., 25% the first year, 50% the second year, and 75% the third year).

Each year you use CGM, the better the results. This is why most gardeners notice a significant difference in their lawns after the third year of application. Therefore, patience (and timing) is essential to the success of CGM.

For more information on how CGM works and helpful tips on how to prep your lawn and successfully apply this pre-emergent herbicide for best results please visit our guide, or contact us.

3 Benefits of Corn Gluten Meal for Lawns

Now that you have some background on this organic solution for weed control, let’s review a few benefits you can expect to see in your landscape.

Natural Weed Control

You probably guessed this one already, but even the most seasoned gardeners struggle with weed growth in their yards.

CGM stops weeds/seeds before they start. By halting cell division in the roots, which seeds rely on to grow during the germination process, CGM helps you get to the ‘root’ cause of your weed problem. And as we noted, the longer you use CGM on your lawn, the more effective it becomes.

Better for Lawn Care

In addition to ridding your lawn of weed growth, CGM won’t harm the surrounding trees and plant life in the process. Because CGM is a natural solution, you don’t need to worry about it changing your soil’s pH or damaging your grass.

Don’t forget, CGM is high in nitrogen (9%), which means it supplies your soil with the food it needs to thrive.

Non-Toxic = No Worries

Aside from the fact that synthetic chemical herbicides cause damage to our soil, grass, and surrounding vegetation, they are also health hazards to our kids and pets. Because CGM is natural, you don’t need to worry about your family coming into contact with toxic chemicals.

Though CGM isn’t harmful, it’s recommended you try to keep ‘Fido’ away from CGM until you water it for the first time. Though CGM is an ingredient in some pet foods, it can give your pets a tummy ache if they eat too much of it in its raw form. Watering it in will reduce or eliminate your pet’s ability to consume it.

Ready for Organic Weed Control?

CGM might just be what you need! Of course, in order for it to be successful, timing and proper application is essential. That’s where we can help!

At Organic Lawns by Lunseth, we have years of experience in carefully and effectively applying OMRI-certified corn gluten to lawns and achieving impressive results that protect your lawn and the environment.

If you’d like to get started, or if you have more questions about this organic method, we encourage you to contact us today!

How to Kill Crabgrass Without Chemicals

Posted on August 13, 2020 | by Organic Lawns by Lunseth

Want to get rid of crabgrass? Chemical weed killer can create problems for your lawn, but organic solutions like corn gluten can prevent crabgrass without harmful toxins. Here’s how to get rid of crabgrass naturally.

How to Get Rid of Crabgrass

Crabgrass is an annual plant that dies off each year, but once you have it, it takes a long time to get rid of it. Each crabgrass plant produces up to 150,000 seeds, and those seeds can stay in your yard for up to three years. As such, it’s much easier to prevent crabgrass than to get rid of it.

How to Kill Crabgrass Naturally

If you’re reading this post, it’s likely you’re already dealing with crabgrass, which means prevention is no longer an option. Though a simple solution may be to kill crabgrass with chemicals, we advise against this for several reasons:

Chemicals leave residue, which can be harmful for pets or children.
Topical treatments can run off into water.
The more you use chemicals, the more you need to use chemicals.

More specifically, many chemical weed killers actually won’t kill crabgrass, and those that kill crabgrass seeds may actually kill your lawn, as well. Why? Because crabgrass is a grass, just like the rest of your lawn. If you do use chemicals, you have to be extremely careful when choosing treatment.

Instead, we believe the best solution is a natural approach. Here’s how to get rid of crabgrass without chemicals.

How to Stop the Plant

Once the plant emerges, you may be tempted to just mow your lawn short and hope that kills the plants, but that’s an ineffective strategy, due to how low the crabgrass grows.

Start by pulling out any plants you see and throwing them away, but don’t use them as mulch or in your compost pile, because they’ll find ways to grow there, too. Do this early in the season, before they can produce seeds.

How To Stop the Seeds

Once the plants are producing seeds, you want to prevent those hundreds of thousands of seeds from germinating.

Using corn meal for crabgrass control is a natural way to stop the seeds from growing, but you must ensure you’re applying it in appropriate amounts—approximately 0.9 lbs. of nitrogen per 1,000 sq. ft. and no more than three times a year. Instead of leaving residual chemicals that can run off into your water supply, corn gluten breaks down quickly, and the nitrogen then turns into a natural fertilizer for the rest of your lawn.

How to Prevent Crabgrass

Instead of treating the crabgrass, treat your lawn as a whole. Good lawn practices are key to preventing the crabgrass from returning. Dense grass will shade the ground, preventing crabgrass seeds from germinating, and deeply watered lawns will kill off shallow-rooted weeds.

Crabgrass grows well in adverse conditions, so the best way to prevent it is to have a dense, healthy lawn without any bare patches. At Organic Lawns by Lunseth, we specialize in creating naturally healthy lawns that are strong enough to fend off crabgrass or other weeds.