How To Get Rid Of Nut Grass (Nutsedge): An Organic Gardener’s Guide

Nut grass, also known as nutsedge, is a common and persistent weed that can be a real headache for gardeners. This hardy plant thrives in warm, wet conditions and can quickly take over your garden if not managed properly. I have been recently asked about how to control this beast of a plant so in this blog post, we’ll explore how nut grass grows, how it spreads, and the best organic methods to get rid of it. We’ll also discuss the optimal times of the year for tackling this tenacious weed to ensure your garden stays healthy and nut grass-free. With the right knowledge and strategies, you can effectively control and even eliminate nut grass from your outdoor space.

Understanding Nut Grass

Nut grass is a perennial plant that belongs to the sedge family. It is not a grass. It has a triangular stem and can grow up to 1.5 feet tall. The plant produces underground tubers, or “nuts,” which are the key to its persistence and ability to spread. It often grows in areas with excessive watering, poor drainage, or compacted soil. The Nutsedges that are found the most in North America are yellow nutsedge (Cyperus esculentus) or purple nutsedge (Cyperus rotundus).

Growth and Spread:

Growth Cycle: Nut grass grows best in warm, wet conditions. It thrives during the summer months, when temperatures are high and moisture is abundant. The rate of growth for nut grass does slow down when the soil dries out a bit.

Spreading Mechanisms: Nut grass spreads through its underground tubers and rhizomes. Each tuber can produce new shoots, leading to the rapid expansion of the plant. The tubers can lie dormant in the soil for years, making it difficult to eradicate. The rhizomes will grow underground spreading like a grass that has runners (like St. Augustine grass) to grow a new plant not far from the original plant. The new rhizomes are whitish and eventually become dark brown and somewhat hard to break.

Nut grass can also spread by seeds if it gets a chance to grow to that extent. I have seen some grow to that point, mainly when they are growing behind another plant and I missed pulling them when I was weeding that area.

Organic Methods to Get Rid of Nut Grass

Getting rid of nut grass organically requires persistence and a combination of methods. Here are some effective strategies to help you combat this weed without using harmful chemicals:

Manual Removal:

How it Works: This is my preferred method for eradicating Nut grass. Manually removing nut grass involves digging up the plants, including their tubers and rhizomes. This method is labor-intensive but effective if done properly.

Steps:

1. Use a garden fork or shovel to carefully dig up the nut grass plants. I usually wait until the soil is pretty moist, such as after a good rain or I water it well before digging.
2. Remove as much of the root system and tubers as possible. If you are not sure if you got the “nut” part of the plant just feel for them. The nuts are hard and easily identifiable after you have dug up a few. The nuts will be smaller for new plants.
3. Dispose of the plants and tubers in a sealed bag to prevent re-spreading.

Solarization

How it Works: Solarization involves covering the affected area with a clear plastic sheet to trap solar energy. The heat generated under the plastic kills the nut grass tubers and seeds. The higher you can get the soil temperature the more successful you will be in getting rid of all of the nutsedge in your garden.

Steps:

1. Mow the nut grass as close to the ground as possible.
2. Water the area thoroughly.
3. Cover the area with a clear plastic sheet, securing the edges with soil or rocks. You can bury the edges if that is easier for you. Do not use white or black plastic since they do not allow enough heat through.
4. Leave the plastic in place for 4-6 weeks during the hottest part of the summer.

Texas A&M Agrilife Extension has a great article on solarization if you want to learn more: Soil Solarization by Joseph B Masabni and Jose G. Franco

Vinegar Solution:

How it Works: A solution of vinegar can be used as a natural herbicide to kill nut grass.

Steps:

1. Mix a solution of vinegar (with at least 20% acetic acid) and water in a spray bottle.
2. Spray the solution directly onto the nut grass, focusing on the base of the plants. Be careful not to spray it on other plants in the area. It will kill them also if you get vinegar on them, as well.
3. Repeat the application every few days until the nut grass dies. It may take several weeks to fully kill nut grass with vinegar. But, vinegar is a much better alternative than using chemicals in your yard. It is also safer if you have animals that frequent your yard.

Eradication and Control of Nut Grass Study

After reading several studies that I found on eradicating nut grass I found one that was interesting. This study is somewhat old but the study was using an organic method to control nut grass so I found it to be valid even in today’s world.

The study conducted found that most nut grass tubers grew only a few inches from the top of the surface of soil. Also, nut grass tubers are rarely found more than 4 inches deep or deeper in the soil. However, one of the trials in this study planted tubers 24″ deep. In 4 months time, 57% of the tubers were able to send shoots to the surface. That was a remarkable amount of time. This plant is a beast.

The study also found that in another trial under favorable conditions a single tuber can infect an area 12 to 14 feet in diameter in one season. These plants were at a normal depth.

The main part of this study found that if they hoed the area under it would eradicate the weed. In the study, they hoed the soil in weekly and biweekly and found that they were able to eradicate the areas tested in two growing years. I have found that if I manually pull the tubers out that I will also have the area completely free of nut grass within this amount of time. This means that no matter what you need to be diligent and patient when trying to get rid of them.

The study measured soil moisture during this time and found that nut grass robbed surrounding area and plants of moisture. It also robbed the surrounding plants of nutrients, as well. This is no surprise but does solidify what we know about weeds in our soil and how they can take the moisture and nutrients for themselves leaving the plants we are wanting to keep without their needed survival components.

Here is a link to the study if you are interested in reading for yourself: Eradication and Control of Nut Grass by C.H. Davis and R.H. Hawkins

Best Time to Tackle Nut Grass

Timing is crucial when dealing with nut grass. The best time to start your eradication efforts is in the early spring before the plants have a chance to establish and spread. Nut grass begins to sprout and grow in the early spring. This is when you need to look for it as it peeks through the soil. By targeting nut grass early in the growing season, you can reduce its impact and make it easier to control.

• Spring: Begin your control efforts in early spring, as soon as you see the first signs of nut grass growth. I also like to pull it now because the soil should be nice and moist. In addition, the newly sprouted nutgrass has not had a chance to spread its rhizomes to surrounding areas. You can stop it before it gets bad and takes over.
• Summer: Continue your efforts through the summer, especially using methods like solarization that require high temperatures.
• Fall: In the fall, focus on manual removal and mulching to prepare for the next growing season.

Prevention of Nut Grass

If nut grass wants to find its way into your yard- it will. However, there are a few things you can do to help keep it at bay.

• “Avoid bringing contaminated soil onto your property. If you are bringing new soil or mulch be careful where you purchase your materials. Even buying “the best” will not fully prevent you getting nut grass seeds or nuts in your yard.
• Be cautious with the plants you buy and watch for newly sprouting nut grass that might make its way into your plants that you bring home.

Conclusion

Nut grass can be a challenging weed to manage, but with persistence, patience, and the right organic methods, you can keep it under control. By understanding how nut grass grows and spreads, and by implementing techniques like solarization, manual removal, and using a vinegar solution, you can protect your garden from this invasive plant. Remember to start your efforts early in the spring and stay vigilant throughout the growing season to achieve the best results. Happy gardening!