CORN GLUTEN MEAL FOR LAWNS
The Best Organic Pre-Emergent for Lawns
Synergy with Corn Gluten Meal
Experience the power of Synergy with Corn Gluten Meal, a natural solution that provides both pre-emergent weed control and fertilization. Derived from a beneficial byproduct of corn syrup production, corn gluten meal has been successfully used to combat lawn weeds for over 30 years. Keep your lawn healthy and control weeds the natural way!
Applied Early Spring and Fall
Applying Synergy before weed seeds germinate—at the recommended rate of 20 pounds per 1,000 square feet—effectively prevents their growth from the start. Many homeowners see up to a 60% reduction in weeds after just one application. For long-term results, applying Synergy in both spring and fall for three or more consecutive years can lead to an impressive 95% decrease in weed growth. Achieve a lush, weed-free lawn naturally, without the use of chemicals!
Approximate Weed Control Rates
Year 1 – 60% Control Rate
Year 2 – 70% Control Rate
Year 3 – 80% Control Rate
Year4+ – 90% Control Rate
Broadcast Application

Organic Weed Control for Lawns
Spring Applications
For the best results, Synergy should be applied in early spring, ideally in March or early April. Corn gluten meal is a powerful natural pre-emergent herbicide, but timing is key—application must occur before weed seeds germinate. It works by inhibiting root development in newly sprouting seeds, preventing weeds from taking hold in your lawn. However, once weeds have already germinated and begun growing, corn gluten meal is no longer effective, as its root-suppressing properties only work during the earliest stages of seed development.
Fall Application
Applying corn gluten meal as a winterizer in the fall offers a powerful dual benefit—nourishing your lawn over the winter while improving weed prevention in the spring. A fall application of Synergy, followed by another application in the spring, provides significantly better weed control than a spring treatment alone. Rich in nitrogen, corn gluten meal also strengthens your grass for the winter, ensuring healthy growth when spring arrives. This unique combination of weed prevention and fertilization makes fall the ideal time to apply corn gluten meal, setting the stage for a lush and healthy spring lawn.
Natural Weed Control for Grass

Naturally Slow Release Nitrogen
Lawns in the Boulder and Fort Collins areas flourish with Synergy, a 100% organic, slow-release nitrogen fertilizer specially suited for Colorado soils. As soil microbes break down the corn gluten meal, nitrogen is gradually released, providing steady, long-lasting nourishment without the risk of burning. This natural process promotes a deep green, resilient lawn that thrives season after season.
Pet Friendly Weed Control

When is the Ideal Time to Apply Corn Gluten Meal Weed Control?
Spring: March 1st – March 31st
Fall: September 23- October 31st
Corn Gluten Meal Application Seasons:
Spring: March 1st – April 15th
Fall: September 15th – November 20th (Whenever the snow won’t allow us to apply)
Derived From:
Corn Gluten Meal for lawns, Bone Meal, and Sulphate of Potash.
Synergy, an all organic pre-emergent weed control, is registered by the Colorado Department of Agriculture, and is recommended for weed control for lawns in the Boulder and Fort Collins area.
Corn Gluten Meal

5 Reasons Why Homeowners Experience Poor Results from Other Corn Gluten Meal Fertilizers
How Much Does Synergy with Corn Gluten Meal Cost?
(303) 499-2000 Boulder or (970) 225-9425 Fort Collins
Corn Gluten Meal Weed Control for Lawns FAQ's
When is the Best Time of Year to Apply Corn Gluten Meal to a Lawn?
Spring and Fall
For optimal weed control, apply corn gluten meal before weed seeds begin to germinate. The best time for application is in early spring, ideally in March or early April, to prevent weed growth while simultaneously fertilizing your lawn. To maximize its effectiveness, reapply in October as a winterizer, strengthening your grass for the colder months. Consistent, seasonal applications enhance its ability to control weeds, leading to a healthier, more resilient lawn over time.
How Does Corn Gluten Meal Work?
Prevents the Secondary Feeder Root
The exact mechanism behind corn gluten meal’s weed-preventing properties isn’t fully understood, but the leading theory suggests that it disrupts early root development. When a weed seed germinates, it sends out a secondary feeder root to absorb nutrients from the soil. Corn gluten meal interferes with this process, damaging the feeder root and preventing the young weed from maturing into an established plant. This natural pre-emergent action helps keep lawns weed-free without the use of synthetic chemicals.
Natural Weed Control

Is Corn Gluten Meal Safe for Kids and Pets?
Made from Edible Ingredients
Corn gluten meal is a food-grade product that is generally considered safe for people and pets, except in cases of corn allergies. A byproduct of corn syrup production, it is derived entirely from corn and commonly used in various food products. It also serves as a filler in some dog foods and plays a role in the brewing process for beer. With its versatility and non-toxic nature, corn gluten meal offers a natural and eco-friendly alternative for lawn care.
Department of Ag Rules
The Colorado Department of Agriculture does not allow any weed control products to be labeled as completely safe. While we cannot explicitly claim that corn gluten meal is entirely risk-free for children and pets, it is derived from edible, food-grade ingredients. As a natural byproduct of corn processing, it is widely used in animal feed and food production, making it one of the safest alternatives for organic lawn care. However, individuals with corn allergies should exercise caution. non-toxic ingredients.
Child and Pet Friendly

Additional Corn Gluten Meal Weed Control FAQs
Posting a pesticide application flag is a legal requirement, even if the product used is 100% organic. This is mandated by the Department of Agriculture. Any product that claims to control weeds must be marked with a pesticide application marker.
Dandelions are biennial plants, meaning they germinate from seed in their first year and then continue to grow from their root system for one to two additional years. Because your lawn naturally has dandelions at various stages of growth, it is important to apply Synergy annually. Synergy only controls weeds that germinate from seed. Therefore, the first application of Synergy will not eliminate dandelions that are sprouting from an established root system. While patience is required when using corn gluten meal, it can be extremely effective when used regularly over a 2-3 year period.
Synergy is a granular product that is applied using a broadcast spreader. However, most spreaders cannot achieve the recommended application rate of 20 pounds per 1,000 square feet. To ensure accurate application, we use specialized Earthway commercial spreaders set to a full open rate.
Corn gluten meal is a byproduct of the corn milling process, primarily used as a high-protein supplement in animal feed. In gardening and lawn care, it is used as an organic pre-emergent herbicide and fertilizer due to its nitrogen content.
To achieve the highest effectiveness in controlling weed germination, we recommend applying treatments in both spring and fall. The spring application not only fertilizes your lawn but also prevents the germination of weed seeds. It should be applied before weed seeds begin to germinate, ideally between March 1st and March 31st. The fall application helps to winterize your lawn by increasing the concentration of corn gluten meal in the soil. If you choose to have a fall application, we recommend applying Synergy again in the spring for optimal results. Using both fall and spring applications can achieve a 60% to 80% effectiveness rate in controlling weed seed germination, while a spring-only application has an effectiveness rate of 40% to 60%.
Corn gluten meal can be moderately effective at controlling weeds in a lawn when used correctly, but its success depends on several factors. As a pre-emergent herbicide, it prevents weed seeds from developing roots after germination, effectively stopping annual weeds like crabgrass, dandelions, and foxtail before they establish. However, it does not control existing weeds or perennial weeds with established root systems.
When applied at the right time—typically early spring for summer weeds and early fall for cool-season weeds—it can reduce weed seed germination by 60-80% over multiple applications. Results are not immediate; repeated, consistent use over 2-3 growing seasons is often necessary to see significant improvement.
Factors such as timing, soil moisture, and application rate impact its effectiveness. Additionally, it requires a sufficient application rate—20 pounds per 1,000 square feet—to achieve the desired results. Overall Corn Gluten Meal works best as part of a comprehensive lawn care plan that includes proper lawn watering practices and lawn mowing techniques.
We tend to see the following weed control rates when using Corn Gluten Meal. We find the best results in the lawns where the homeowners are also following our watering and lawn mowing recommendations.
- First Year = 60% control rate
- Second Year = 70% control rate
- Third Year = 80% control rate
- Fourth Year = 90%+ control rate
Synergy is a pre-emergent weed control product, which means it prevents weed seeds from germinating and developing properly. However, it does not kill existing weeds. Additionally, since it may affect grass seeds, we do not recommend applying this product if you plan to plant grass in the next 2 to 4 weeks.
This product is an organic pre-emergent, which means it will not prevent all weeds from germinating—only those that grow from seeds. If used in combination with One Earth Weed Killer as part of a full season program, you can expect to achieve a mostly weed-free lawn within a year, provided you also follow proper cultural practices like mowing and watering.
Instant results are not something that Synergy can guarantee. If you are looking for a completely weed-free lawn after just one application, it’s important to understand that organic lawn care is a gradual process. However, with patience and consistent effort, this program can be very effective.
To effectively control weeds, Corn Gluten Meal should be applied at a rate of 20 pounds per 1,000 square feet or more. In comparison, most chemical fertilizers are typically applied at a rate of only 2 to 4 pounds per 1,000 square feet, meaning that a greater quantity of product is needed when using Corn Gluten Meal.
Yes, corn gluten meal is rich in nitrogen, containing about 10% by weight. This makes it a beneficial slow-release fertilizer that can help promote healthy grass, stimulate microbial activity, and promote plant growth while controlling weeds.
You can use corn gluten meal in vegetable gardens, but caution is needed. Since it inhibits seed germination, it should not be applied where you plan to sow seeds. It’s best used around established plants or transplants to control weeds without affecting your vegetables.
Note that Organo-Lawn will not apply any product to vegetable gardens, but we do sell bags of Synergy for homeowner use.
It is possible but unlikely. Organic nitrogen sources like the one from Corn Gluten Meal can leach into the water supply under rare conditions, though the risk is dramatically lower compared to synthetic nitrogen fertilizers. Organic nitrogen sources, such as compost, manure, or plant-based materials (e.g., alfalfa meal), release nitrogen only through microbial activity. This gradual release dramatically reduces the immediate risk of leaching and if leaching does occur it is only a fraction of the total nitrogen.
Unfortunately, 99.7% of the corn produced in the U.S. is not organically grown. While there is organic corn gluten meal available, it is priced at four times the cost of conventional options. This high price makes it prohibitive for most people to purchase.
Yes, it contains about 10% nitrogen, which feeds the grass and promotes lush, green growth.
Accordion Content
The corn gluten meal that is used in Synergy is most likely derived from conventional field corn, which often includes genetically modified (GMO) varieties. We have sourced GMO-free corn gluten meal, however, the price difference for a certified organic corn gluten meal is significantly higher.