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.

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.

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.

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.

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Related Links

• Cover Crop Seed Suppliers
• Cover Crop Seeds Available
• Soil Management: Cover Crops
• Soil Management
• Soil Water Management
• Publication 75, Guide to Weed Control
• Agronomy Guide - Other Crops
• Midwest Cover Crop Council Cover Crop Decision Tool