How to Manage Waterhemp in Soybeans

FBN Network

Jan 15, 2024

Waterhemp (Amaranthus tuberculatus), a summer annual weed from the pigweed family, has become a significant concern for soybean fields throughout the Midwest. Its rapid growth rate, high seed production, and resistance to multiple herbicide classes make it a formidable foe. A single Waterhemp plant can produce up to a million seeds.

According to the University of Missouri Extension, even a moderate Waterhemp infestation can slash soybean yields by 44%. 

Waterhemp impacts soybean plants in several significant ways:

1. Resource Competition: As a highly competitive weed, Waterhemp vies with soybean plants for water, nutrients, and sunlight. This competition can stunt growth and reduce yields in soybean plants.

2. Harvesting Interference: Mature Waterhemp plants can disrupt combine operation during soybean harvest, leading to increased harvest time and cost.

3. Herbicide Resistance: Waterhemp's resistance to multiple classes of herbicides complicates its control. This resistance can lead to increased herbicide use, resulting in higher production costs and potential environmental impacts.

This post will outline:

  • How to identify Waterhemp

  • Geographic impact of Waterhemp

  • Timing of Waterhemp

  • How to manage Waterhemp in soybeans

How to Identify Waterhemp

Waterhemp, a tall, erect, branching plant, can reach heights of up to 8 feet. It boasts long, narrow leaves that are typically smooth and shiny. The stems, hairless and varying in color from green to red, support small, green flowers found on long, slender spikes at the top of the plant and in the leaf axils.

While Waterhemp seedlings may be challenging to distinguish from other pigweed species, mature plants reveal distinct characteristics. The absence of hair on the stem and leaves, longer and narrower leaves, and more prolific branching differentiate Waterhemp from its pigweed relatives.

Geographic Impact of Waterhemp

Native to the Midwest, Waterhemp has expanded its reach to other parts of the United States and Canada. It is commonly found in corn and soybean fields, pastures, and roadsides.

Timing of Waterhemp

Unlike other weeds, Waterhemp typically emerges later in the growing season, from late spring through mid-summer, posing a threat throughout the entire growing season.

How to Manage Waterhemp in Soybeans

Accurate identification, understanding its impact, and implementing effective management strategies are paramount in controlling this persistent weed.

To manage Waterhemp in soybeans, consider these products: 

Following the instructions provided on the labels ensures proper and effective use of these products.

There are also non-chemical approaches to managing this weed. Research at the University of Wisconsin-Madison indicates that narrow row spacing in soybeans helps reduce Waterhemp issues. Combining this method with effective herbicides provides integrated management. 

Crop Protection from FBN®

Proactively scouting for and responding to weeds in your fields will help reduce potential crop damage and improve yield. FBN has a wide variety of effective herbicides to help address agronomic pressures and keep your operation on track. 

With transparent pricing, straightforward online ordering, detailed product labels, and fast direct-to-farm delivery, FBN can help you get the products you need to protect your crops.

Related Resources

© 2014 - 2023 Farmer's Business Network, Inc. All rights Reserved. The sprout logo, “Farmers Business Network”, “FBN”, “FBN Direct” are trademarks or registered trademarks of Farmer's Business Network, Inc. This content was written by Norm℠, reviewed and edited by Mikaela Tierney.

This content was generated with the assistance of Norm℠, FBN’s artificial intelligence (AI) Ag Advisor, based on a dataset of information containing general industry best practices and research. The AI model did not use specific external sources to generate this content. Our process involves using AI to aid human subject matter experts with the initial drafting and/or refinement of content. 

The information and content provided is believed to be reliable, but its accuracy is not guaranteed. The content is provided for informational purposes only. It is not intended to be a substitute for specific agronomic, business, or professional advice, and should not be relied upon as such. Neither Farmer's Business Network Inc. nor any of its affiliates makes any representations or warranties, express or implied, as to the accuracy or completeness of the statements or any information contained in the material and any liability therefore is expressly disclaimed. If you have any questions or feedback about the content, please feel free to contact us or visit our FAQ (

FBN Direct products and services and other products distributed by FBN Direct are offered by FBN Inputs, LLC and are available only in states where FBN Inputs, LLC is licensed and where those products are registered for sale or use, if applicable. If applicable, please check with your local extension service to ensure registration status. Nothing contained on this page, including the prices listed should be construed as an offer for sale, or a sale of products. All products and prices are subject to change at any time and without notice and excludes CA mills tax and MN ACRRA fees. Terms and conditions apply.

ALWAYS READ AND FOLLOW LABEL DIRECTIONS. It is a violation of federal and state law to use any pesticide product other than in accordance with its label. The distribution, sale and use of an unregistered pesticide is a violation of federal and/or state law and is strictly prohibited. We do not guarantee the accuracy of any information provided on this page or which is provided by us in any form. It is your responsibility to confirm prior to purchase and use that a product is labeled for your specific purposes, including, but not limited to, your target crop or pest and its compatibility with other products in a tank mix and that the usage of a product is otherwise consistent with federal, state and local laws.  We reserve the right to restrict sales on a geographic basis in our sole discretion. You must have a valid applicator license to use restricted use pesticides.  Please consult your state department of agriculture for complete rules and regulations on the use of restricted use pesticides, as some products require specific record-keeping requirements.

All product recommendations and other information provided is for informational purposes only. It is not intended to be a substitute for consulting the product label or for specific agronomic, business,or professional advice. Where specific advice is necessary or appropriate, consult with a qualified advisor. Neither Farmer's Business Network Inc. nor any of its affiliates makes any representations or warranties, express or implied, as to the accuracy or completeness of the statements or any information contained in the material and any liability therefore is expressly disclaimed.

FBN Network

Jan 15, 2024

Download Crop Nutrition Guide
Boost your crop vitality with the Farmers First™ portfolio.
FBN® Land Loans
Save thousands by financing your farm at a great rate.