Interseeding Between Corn
alternative practice names:
Interseeding; Row Intercrops; Alternating Crops; Skip Rows
Interseeding between corn rows involves planting a secondary crop, such as a cover crop or alfalfa, into a standing corn crop. In corn systems, interseeding can be done with a wide variety of equipment at different stages of the corn crop cycle.
At planting: Alfalfa can be interseeded into corn early in the crop cycle. Research suggests that this is best done at or shortly after planting and before the V2 stage to allow alfalfa enough time to establish without competing heavily with the corn. No-till drills are commonly used for this purpose.
Early corn development (V3 to V6): Grasses and legumes can be interseeded between corn rows V3 and V6 stages of corn development after the corn is established but before the canopy closes. This allows the interseeded crop enough light establish before the corn canopy closes. Specialized no-till drills or interseeders are typically used to minimize disturbing the growing corn. The use of standard 30" rows or wider 60" row configurations supports different objectives; wider rows provide more consistent light for cover crops throughout the season for farms interested in grazing or harvesting the cover crop as feed.
Before harvest: Cover crops can be interseeded within corn two to four weeks before corn silage harvest or when leaf senescence begins in grain corn. Cover crops can be interseeded via aerial application or high-clearance equipment (such as a highboy retrofitted with drop tubes), allowing interseeded crops to be established before corn harvest. While this method is more common in grain corn operations, where the later harvest provides a longer window for establishment, it can also be applied to corn silage systems where post-harvest planting opportunities are more limited.
Each method aligns with specific crop systems and goals, such as improving soil health, enhancing forage production, and reducing erosion, offering flexibility based on the farm's management practices.
When used, in what regions in the U.S. is the practice found:
Northwest, Upper Midwest, Northeast, Southeast
FARM SIZE
When used, typically found on farms of the following sizes:
All Sizes

Practice Benefits
Improved soil health and reduced erosion: Interseeding cover crops into corn systems increases biomass, which helps prevent soil erosion and improves soil structure. The cover crops promote nutrient cycling and enhance water retention, leading to healthier, more resilient soils.
Weed suppression: Cover crops interseeded between wide rows provide ground cover that helps suppress weed growth by outcompeting weeds for resources, reducing the need for herbicides.
Improved labor distribution: Interseeding allows farmers to plant cover crops earlier in the season, before the busy period of corn silage harvest, hay harvest, manure application, and silage packing, all of which compete for limited labor resources. By interseeding cover crops, farmers can move the planting activities to a less hectic part of the cropping season, reducing labor strain and improving overall efficiency.
Extended grazing opportunities: Interseeded cover crops can be used as forage, providing an extended grazing season for livestock, which can reduce feed costs and increase farm revenue.
For additional information, see Cover Crops: Non-Feed and Cover Crops: Forage.

Implementation Insights
Site-specific or Farm-specific requirements

Water availability: Interseeding in a row crop system may be ill-advised in a water-scarce area. However, interseeding may be beneficial in areas prone to flooding or prolonged periods of saturation as the live plants may help dry out a field faster.
Required Capital Expenditures (CapEx)

No-till drill: A simple no-till drill can be used for interseeding alfalfa shortly after planting corn.
High-clearance no-till drills: These "interseeders" are equipped with planting units spaced to accommodate corn or soybean rows. This method promotes excellent seed-to-soil contact.
Broadcast seeder mounted on cultivation equipment: This setup is particularly useful for planting cover crops during the final cultivation before canopy closure, especially in organic systems.
Modified air seeders: These are adapted to feed individual row units, typically spacing 2-4 units between each row of the main crop, allowing for even distribution of cover crop seeds.
Retrofitted highboys: High-clearance sprayers, commonly used for pesticide applications, can be retrofitted with a seed box and drop tubes to deliver seeds efficiently between crop rows.
Fertilizer spreader: Cover crops can be planted using a fertilizer spreader designed for side-dressing by itself or with additional fertilizer as part of a split application practice.
Required Operational Expenditures (OpEx)

Higher seed costs: When cover crops are surface-applied, they may face lower germination rates due to reduced seed-to-soil contact and environmental factors, such as dry conditions. This often necessitates using higher seeding rates, which increases costs. Coated seeds can also contribute to increased costs, as they are sometimes used to enhance establishment in less-than-ideal conditions.
Equipment rentals or custom applicator fees: Farms that do not own the necessary equipment for interseeding, such as a no-till drill, may opt to rent equipment or hire custom applicators.
Aerial seeding fees: Aerial application methods, such as using airplanes, helicopters, or drones, are another option for interseeding. Hiring professional pilots is necessary due to the specialized skills and equipment required, and this method can increase costs. Often, higher seeding rates and the use of coated seeds are needed, further raising expenses. Additionally, there may be minimum acreage requirements to make hiring an airplane or helicopter viable, though coordinating with nearby farms can help meet those minimums.
Implementation Considerations

Potential cash crop yield reduction: Interseeding introduces the risk of competition between the interseeded crop and corn for light, moisture, and nutrients, which can lead to reduced corn yields. This yield drag is particularly pronounced when cover crops are not carefully managed or timed.
Challenges in interseeded crop growth: Success with interseeding is highly variable and depends on several factors, including weather, soil conditions, canopy cover, and management practices. This variability makes consistent and reliable implementation difficult.
Modifications to the corn crop system: To accommodate interseeding, farmers may need to modify their corn cropping systems, such as increasing row spacing to allow more sunlight for cover crops. However, wider rows can reduce corn yields, and adjusting plant populations to compensate can be challenging. Selecting corn hybrids with a vertical leaf structure can improve light availability but may compromise yield or forage quality, particularly in silage systems.
Seed selection: The choice of interseeded crops is crucial. Cover crops should be fast-growing, shade-tolerant, or able to germinate and thrive once the corn canopy opens after harvest. The balance between quick establishment and compatibility with the corn crop’s growth stage is key.
Planting method: Choosing the right planting method is essential for successful interseeding. While broadcasting seeds, especially in later stages, is common, it often leads to poor establishment without proper seed-to-soil contact. Establishing crops with a no-till drill or interseeding earlier in the season tends to improve success. If broadcasting, especially via aerial application, using coated seeds and timing the planting with rain can enhance results.
Herbicide management: Herbicide carryover poses a significant risk to cover crop establishment, especially with early interseeding. Selecting herbicides that do not persist in the soil or using a burndown treatment like glyphosate before planting can mitigate this risk.
Harvest impacts: Harvesting corn over interseeded cover crops presents challenges, as heavy machinery can damage or destroy the cover crop, especially in wet conditions. Controlled traffic during harvest can help minimize damage, though this is often difficult in silage operations. Farmers may face tough decisions between optimizing forage quality and preserving the cover crop.
Financial Considerations and Revenue Streams
FEDERAL COST-SHARE PROGRAM
Funding is available for this practice through USDA's Natural Resources Conservation Service (NRCS) Environmental Quality Incentives Program (EQIP).
Related EQIP Practice Standard: Cover Crop (340).
Notes:
Federal funding can generally be used to interseed cover crop into a standing cash crop via aerial seeding or high clearance sprayer, provided farmers adjust seeding rate to account for lower germination potential.
Check with the local NRCS office on payment rates and crop rotations relevant to your location.
Check both cost-share and crop insurance requirements specific to your area and program.
CARBON CREDITS
This practice is commonly credited in carbon markets. The practice can generate both offset and inset credits.
Notes:
The impact of diverse crop rotations is primarily estimated through scientific modeling in the project and would use farm management information including planting, harvest, tillage, fertilizer, irrigation, and grazing information from the year the change happened and likely three years before.
Only new practices are eligible for crediting under most offset and inset programs, though existing conservation practices may increrase the emissions reduction estimates under both offset and inset opportunities.
Offset removals in soils created by this practice typically need to be guaranteed for 50-100 years (see Verra methodology and Climate Action Reserve's Soil Enrichment Protocol). The practice does not necessarily have to be maintained that long, rather conservation practices as a whole need to continue to maintain the soil.
Producers generally contribute to a buffer pool to insure against risks of natural disasters or unintentional reversals of sequestered carbon. Intentional reversals, from intensive tillage or land sales, may require operators to return proceeds from the project.
The length of an inset project is more flexible, determined in agreement with the supply chain partner.
Additional Resources

Environmental Impacts
REDUCES FARM GREENHOUSE GAS FOOTPRINT
The impact of interseeding on a farm's greenhouse gas (GHG) footprint depends on both the type of crop being interseeded and how that interseeded crop is utilized. In some cases, interseeding can enhance soil carbon sequestration, particularly when cover crops are terminated and incorporated into the soil. Alternatively, when interseeded crops are harvested for feed, they can reduce the GHG footprint associated with feed production.
For more detailed information, see Cover Crops: Forage, Cover Crops: Non-Feed, and Diverse Forage Crop Rotation: Alfalfa.
IMPROVES WATER QUALITY
Cover crops established through interseeding help protect the soil from wind and water erosion, particularly during vulnerable times when the main crop isn't providing full ground cover. Interseeding enhances soil structure by increasing organic matter and promoting soil aggregation, which helps reduce erosion and compaction. This improves water infiltration and retention, which is particularly important in regions prone to drought or heavy rainfall. Lastly, interseeding reduces nutrient runoff, especially nitrogen and phosphorus, by scavenging residual nutrients in the soil.
REFerences

Alignment with FARM Program
This practice is not included in the FARM program.
Contents
We're always eager to update the website with the latest research, implementation insights, financial case studies, and emerging practices. Use the link above to share your insights.
We're always eager to update the website with the latest research, implementation insights, financial case studies, and emerging practices. Use the link above to share your insights.
Interseeding between corn rows involves planting a secondary crop, such as a cover crop or alfalfa, into a standing corn crop. In corn systems, interseeding can be done with a wide variety of equipment at different stages of the corn crop cycle.
At planting: Alfalfa can be interseeded into corn early in the crop cycle. Research suggests that this is best done at or shortly after planting and before the V2 stage to allow alfalfa enough time to establish without competing heavily with the corn. No-till drills are commonly used for this purpose.
Early corn development (V3 to V6): Grasses and legumes can be interseeded between corn rows V3 and V6 stages of corn development after the corn is established but before the canopy closes. This allows the interseeded crop enough light establish before the corn canopy closes. Specialized no-till drills or interseeders are typically used to minimize disturbing the growing corn. The use of standard 30" rows or wider 60" row configurations supports different objectives; wider rows provide more consistent light for cover crops throughout the season for farms interested in grazing or harvesting the cover crop as feed.
Before harvest: Cover crops can be interseeded within corn two to four weeks before corn silage harvest or when leaf senescence begins in grain corn. Cover crops can be interseeded via aerial application or high-clearance equipment (such as a highboy retrofitted with drop tubes), allowing interseeded crops to be established before corn harvest. While this method is more common in grain corn operations, where the later harvest provides a longer window for establishment, it can also be applied to corn silage systems where post-harvest planting opportunities are more limited.
Each method aligns with specific crop systems and goals, such as improving soil health, enhancing forage production, and reducing erosion, offering flexibility based on the farm's management practices.
Practices and technologies
Interseeding Between Corn
alternative practice name:
Interseeding; Row Intercrops; Alternating Crops; Skip Rows