Pre-season asparagus weed control

Asparagus spears in various stages of emergence at Schmidt Farm in Preston, MN. Photo: Annie Klodd

 Author: Annie Klodd, UMN Extension Educator - Fruit and Vegetable Production

Our warm spring will likely bring an earlier-than-average asparagus spear emergence. Emergence typically starts in mid-late April, depending on location and weather. Can you believe we're almost at asparagus season? 

For those using herbicides in your asparagus weed management plan, an application prior to spear emergence will help reduce in-season weed problems. It will also reduce the need for cultivation, which disturbs the soil structure and can damage spears. Do not wait until the spears have emerged to start thinking about weed control - it will be too late for most herbicides at that point. In-season weed control is challenging and labor intensive, as herbicide options are extremely limited once spears emerge.

• Solid asparagus herbicide programs use both preemergent and postemergent products, and rotate between modes of action to reduce the risk of herbicide resistance. 
• Read the labels carefully before applying. Understand which products are currently labeled in Minnesota. Watch for updates on Minnesota 24c special labels, from MFVGA.
  
• Organic growers rely heavily on hand-weeding in asparagus; however, cover cropping, flaming, and light cultivation can also be integrated if the grower finds them to be suitable strategies for their farm.

We have already published asparagus weed management recommendations, so I will link those resources here rather than re-writing them all:

This UMN Extension article from 2020 describes integrated weed management (IWM) strategies for asparagus, including conventional and organic options, and provides information about herbicides labeled for use in asparagus: https://blog-fruit-vegetable-ipm.extension.umn.edu/2020/06/weed-management-options-for-asparagus.html

Additionally, please refer to the Midwest Vegetable Production Guide for Commercial Growers, page 92 for asparagus herbicide options. 

The (NEW!) Growing Asparagus in Minnesota guide by UMN Extension and SFA goes into detail on organic, sustainable and non-chemical management practices for growing asparagus, from planting to pest management to harvest.