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, depending on the crop being grown
  • There are no herbicides registered to control broadleaf weeds in buckwheat but some 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.



For more information:
Toll Free: 1-877-424-1300
E-mail: ag.info.omafra@ontario.ca