Controlling Pigweed with Minimal Tillage in Fall Vegetable Crops

March 17, 2020

Managing and controlling weeds is an ongoing challenge and frustration for many farmers, but it can be especially cumbersome for organic producers, whose options for herbicides are limited. For these organic producers, no-till and conservation tillage systems can help conserve soil and can be used for weed control.

Tom Buller, a vegetable grower and extension agent with Kansas State University in Douglas County, knew that farmers in his area were struggling with pigweed. Buller was interested in trying some minimal tillage techniques to manage weeds using occultation, a power harrow, and flame weeding to create a stale seedbed. He received an NCR-SARE Partnership grant for $29,495 to work with three nearby farmers to learn more about controlling pigweed in their fall-grown, direct-seeded spinach, beets, and carrots.

With the drought in 2018, extremely wet weather in 2019, and extensive deer damage, the timing was the biggest challenge for testing these weed suppression methods. Ultimately, Buller said that it seemed like using the various methods together would more effective than using them by themselves.

"In a perfect world, a better process might be using these methods together. It would be a two(+)-month process," explained Buller.

Here is the process Buller described:

  1. start with a relatively clean field with minimal plant material
  2. fertilize and prepare beds with a power harrow
  3. if no rain comes, overhead irrigate, then cover with a tarp and leave for 6 weeks to kill most viable surface weed seed
  4. pull back tarp, overhead irrigate again to sprout any remaining weed seeds and wait for a week (or so)
  5. flame weed any weed seeds that sprouted from irrigation
  6. seed crop into flame weeded beds

Buller reported that the project led to ongoing engagement to help other farmers with weed management challenges in northeast Kansas.

"A specialty crop block grant was received by K-State Research and Extension Douglas County to, in part, provide education on weed control and other topics to beginning farmers," said Buller. "The information gleaned in this project will inform that effort directly."

View Related SARE Grant:

Related Locations: North Central