Cover Crops: Buckwheat

Table of Contents

  1. Description: Family
  2. Cover Crop Use
  3. Growth Habits
  4. Control Options
  5. Sensitivity to Herbicides
  6. Weed Control
  7. Benefits and Concerns
  8. Getting Started
  9. Related Links

Description

Family

  • Polygonaceae (smartweed)
  • broadleaf
  • summer annual

Cover Crop Use

  • after early harvested crops
  • as a weed suppressant/smother crop
  • as a pollen source

Figure 1. Buckwheat seedlings emerge and grow quickly.

Figure 1. Buckwheat seedlings emerge and grow quickly.

 

Growth Habits

Germination

  • germinates at a soil temperature of 7.0° C or higher
  • emergence usually 3 to 5 days after planting

Top Growth

  • fastest growing cover crop
  • flowers in 4 to 6 weeks and sets seed in 10 to 12 weeks
  • there can be mature seeds on plants that are still flowering
  • single-stem with height of 30 to 150 cm, usually 45 to 75 cm in 6 weeks

Root System

  • fibrous root system, moderately aggressive
  • concentrated in top 25 cm
  • root biomass is much less than cereals

Overwintering

  • very cold sensitive
  • easily killed by frost

Site suitability

  • wide range of soil types
  • prefers well-drained soils with a pH range of 5.0 to 7.0
  • performs well on infertile soils
  • intolerant of droughty, saturated or compacted soils

Control Options

  • do not let buckwheat go to seed - there’s a fine line between attaining maximum biomass and allowing the crop to go to seed
  • for best results - kill buckwheat within 7 to 10 days of flowering - before the seed matures
  • volunteer buckwheat can be controlled by several broadleaf herbicides containing triazine, sulfonylurea and trifluralin.

Sensitivity to Herbicides

  • seedlings have been damaged from residues from herbicides containing triazine, sulfonylurea, and trifluralin

Figure 2. Buckwheat provides rapid ground cover.

Figure 2. Buckwheat provides rapid ground cover.

Weed Control

  • A good stand of buckwheat can usually compete well with most weed species
  • Volunteer buckwheat can be controlled by several broadleaf herbicides including Target, Pardner and Buctril M, depending on the crop being grown
  • There are no herbicides registered to control broadleaf weeds in buckwheat but Poast Ultra can be used to control some grass weeds in this crop

Benefits and Cautions

Nutrient Management

  • effective at extracting phosphorus from the soil - used by organic farmers for this purpose

Pest Management

  • smothers annuals, suppresses and shades perennial weeds
  • attracts beneficial insects
  • honeybees are attracted
  • attract Lygus bugs and tarnished plant bugs
  • should not be used in a field with history of root lesion nematode
  • prone to white mold and Rhizoctonia

 

Figure 3. Buckwheat flowers are attractive to pollinators.

Figure 3. Buckwheat flowers are attractive to pollinators.

Organic Matter

  • not a big biomass producer, especially if planted late summer
  • easily decomposable residue

Erosion Control

  • rapid growth and umbrella like leaf structure, means fastground cover

Getting Started

Establishment

  • plant buckwheat in the spring after all risk of frost is past or late summer at least 4 weeks before the usual frost date
  • seeding rate of 50 to 60 kg/ha - use higher rates if broadcasting
  • drilling is a better option - results in even placement and solid stands
  • can be killed by early frost

Seed Cost & Availability

  • moderate planting expense
  • if not available locally, usually can be ordered in

Cover Crop Management

  • monitor buckwheat carefully to prevent seedset

Figure 4. Buckwheat sets seed early, while still actively flowering.

Figure 4. Buckwheat sets seed early, while still actively flowering.


Related Links


For more information:
Toll Free: 1-877-424-1300
E-mail: ag.info.omafra@ontario.ca
Author: Anne Verhallen - Soil Management Specialist (Hort Crops)/OMAFRA; Adam Hayes - Soil Management Specialist (Field Crops)/OMAFRA; Ted Taylor - Technical Coordinater, BMP Program/OMAFRA
Creation Date:
June 2001
Last Reviewed:
17 April 2012