Organic Agriculture

This page provides overviews of several important aspects of organic agriculture production such as roller crimping, weed control, and disease management.  These sections can be navigated using the "Jump to a Section" feature below or feel free to scroll through the page.

If you are just getting into organic agriculture, you may find this free Guide for Organic Crop Producers from ATTRA helpful, which is intended to lead farmers through the organic certification process.

Roller Crimping

Roller crimping is a technique used to terminate cover crops ahead of no-till planting a cash crop. It is a high management system that requires an adaptive management approach. Roller crimping is most commonly adapted to terminating cereal rye cover crop ahead of no-till soybean production in US cropping systems. 

Roller crimping may be right for you if you are...

  • An experienced no-tiller
  • Growing later planted soybeans
  • Willing to plant green or into high residue
  • Comfortable with cereal rye cover crop potentially setting viable seed (for those raising small grain crops, this is a major risk to be managed or completely avoided)
  • A farmer looking to reduce tillage and/or herbicide use
The Purdue Extension Organic Agriculture Program is proud to offer a roller crimper available for lending for any operation. To learn more about our roller crimper, contact Ashley Adair

Quick Guide to Roller Crimping for Organic and Non-Organic Operations

  • Variety matters.
    • Variety Not Stated (VNS) potentially has multiple varieties or a range of maturity dates. Consistent phenological development of the cover crop is crucial to high termination rates with roller crimping.
    • Early flowering and high biomass production are keys to preserve soybean planting date and suitable weed control.
  • To achieve earliest planting date of soybeans, plan to use Aroostook or Elbon cereal rye varieties. Other varieties are being evaluated--consider evaluating varieties on your farm in strip trials or plots. VNS sources generally result in 2 weeks later and uneven flowering relative to the stated/named varieties above.
  • Farmers and researchers are also evaluating the potential of hybrid rye varieties and triticale varieties in comparison to OP rye cover crop varieties.

  • While seeding rate is important, the goal is establishing a good stand of cover crop to achieve consistent cover with adequate biomass production for maximum weed suppression during the growing season.
  • Seeding before October 10 in Northern and Central Indiana should be your target, or earlier. Earlier seeding provides for more fall tillering, resulting in suppression of winter annual weeds and more biomass production for the next year’s soybean crop. More biomass provides for better termination with roller crimping and greater weed control.
  • Be on time to make the system work. Explore shorter day corn or alternative crop rotations to create this early seeding window. Treat the cover crop as you would a cash crop!
  • Seeding can be accomplished with drill, broadcast and incorporate, or precision planting, but each method has pros and cons and must match your goals, equipment, and logistics. Aerial seeding into standing crops is not recommended for this system of management due to limited coverage and reliability of stand establishment
    • Drill and planting provides the most consistent stands and even emergence, especially when planting later and in drier conditions, but are slower operations relative to broadcast and incorporation. Drilling and planting also create inter row space without cover creating niches for some weeds to possibly get established. For more coverage, consider double drilling/planting at an offset angle.
      • Crimp at an angle offset to the direction of cereal rye planting to maximize soil cover in the spring.
    • Broadcast with incorporation is fast and is a good way to utilize manure and take out a flush of weeds in an organic system. It also provides full coverage with no inter-row space. Broadcast allows for crimping in any direction if soil coverage is primary goal.
  • Seeding 2-3 bushels of cereal rye with little Nitrogen if seeding late or in an organic system, consider higher seeding rate, up to 3 bushel and top dressing with N in spring.
  • One could also top dress with 30 lb/a in March to help compensate for later planting, but nothing truly compensates for timely fall seeding of the cover crop
  • If crimping in combination with herbicide application in a non-organic system, a little herbicide goes a long way. Also, consider whether you need to knock down the cover crop with a roller crimper when using herbicide; some non-organic farmers just plant into rye and burn down the cover crop without rolling. A rolled cover crop may provide more weed suppression and late season moisture retention, but also makes for a “cleaner” looking field as the soybean crop emerges and gets established.

  • Evaluate cereal rye cover crop stands in March/April.
    • Thin strands of cereal rye will not terminate well and will only provide weed control for a short time frame. ○5,000-8,000 pounds/ac of biomass is a minimum for season-long weed control in organic systems at anthesis.
    • Are weeds already present, gaps in cereal rye stand, how will these be managed?
    • If managing in an organic system, you must assess weed pressure and uniformity of the stand of cereal rye. If weed pressure is high and/or the rye stand is weak or inconsistent, consider going to plan B: incorporate the rye as green manure and manage the soybean crop with cultivation.

  • The tool may be the least important aspect of this system.  It is the full system of management that will provide consistent results. 
  • The goal is to crimp not cut the cover crop. 
  • Several roller-crimper designs exist and have pros and cons.  Know your situation and challenges. Key considerations with roller crimping 
    • A minimum of 200 pounds per linear foot of tool width is required for good mechanical termination. Filling the roller-crimper drum with water is the most common way to attain this weight, but be creative if that is not an option with your tool. 
    • The chevron pattern of the Rodale-style roller-crimper will not generate excessive vibration or bounce at high speeds compared to a roller with parallel blades 
    • The tool must be set on “float setting” on the tractor to ride with the ground topography.
  • If you’re using herbicide in a non-organic system, rolling may be all you need, since the crimping action won’t be needed to terminate the cover crop. 
  • Crimping pinches the stem between the tool and the soil, terminating cereal rye by disrupting the flow of water and nutrients in the plant. 
  • Front or rear mounting the tool works, but the front mount is generally preferred to minimize the need to crimp rye that is rolled down in tractor wheel tracks. 
  • If you have rolling ground, consider using a narrower tool, or narrow tool sections if a folding tool, to provide for better ground contact


  • Species must be at the right growth stage (anthesis) to terminate.  This is not determined by the planting date.  Know the growth stages and be willing to wait.  
    • Full flower or anthesis.  View growth stages here. 
  • Waiting two days can make a big difference to attain full flower, which should result in a 95% termination rate. 
  • Cereal rye must be at full flower (anthesis) to reach 95%+ termination rate by crimping.  Flowering begins in the middle of the flowering head and then moves up and down.  Wait for the pollen anthers to be at the top of the head.  If anthers have blown off in the wind, you may have to look on the ground.   
  • Pollen may clog your tractor radiator screen and intake filter when roller crimping cereal rye in full flower 
  • In dry springs or sandy soils, cereal rye will reduce root zone moisture for soybeans. Irrigation is a nice backup if you have fields with irrigation systems. Later in summer, the mat of cereal rye biomass has an opposite effect, holding soil moisture and releasing some nitrogen for soybean filling. 

  • Most farmers find It is easier to plant first, then roller crimp.  But every situation and season is different:  
    • Roll when the time to roll.  If cereal rye is tall and a storm threatens to lodge the cereal rye, then plant before crimping if you have time, or crimp before the storm hits.  If you crimp before planting, and a rainfall pattern sets in, the thick mat will hold moisture and make it hard to get back in the field if soil moisture is high   Once the cereal rye is terminated, it will stop evapotranspiration.  
  • Increase soybean seeding rate by 10-15%. 
    • Thicker cereal rye mulch presents a challenge to soybean germination and emergence. 
    • Higher soybean seeding rates can be viewed as low-cost insurance and good weed suppression. 
    • Many organic farmers working with this system are seeding at 200,000+ seeds/acre. 
  • If you crimp first, you will need to plant in the same direction of crimping. 
    • Planting into lodged cereal rye is not easy, do not over-fertilize the cereal rye to limit this potential, and plant ahead of big wind storms if necessary.  If you plant at a direction opposite of the crimping direction (or lodged), the planter will be challenged to cut through the biomass which could result in hairpinning.
  • Planting at the boot stage of cereal rye provides for earlier planting dates.  
    • The boot stage occurs when the head (and awns of the flowering head) are about to emerge from the stem.  Growth stages can be viewed here.
    • Soybeans emerged in uncrimped cereal rye can be crimped at 1st to 3rd trifoliate stage (V1-V3) with no significant loss to soybean stand, if cereal rye mat is thick enough. 
    • Avoid crimping when soybeans are at the crook stage during emergence (VE). 
    • Plating at the boot can result in reduced percent termination of rye, increasing viable rye seed production.  Recent on-farm results and research trials suggest that some rye varieties may be more “stressed” during early planting, resulting in more tillers and/or inconsistent phenological development, reducing percent kill with roller crimping once the beans reach V1-V3. 
  • Think about your drill/ planter setup 
    • Drilling at 7.5 inches may achieve greater weed control from earlier canopy but leave no “rescue” cultivation options. 
    • Planting at 15 inches may result in more even emergence, but there is limited data on this reality. 
    • High residue row cultivators can be used in crimped cereal rye when planting at 30” row spacing.  A weed zapper could also be navigated through 30” row beans with limited tractor tire damage of the soybeans compared to narrow row beans.  Increasing seeding rates at 30” can help with in-row weed suppression with earlier stem elongation and in-row shading. 
    • Extra weight is sometimes needed to penetrate through cereal rye mulch, particularly when planting after crimping. 
  • A sharp lead coulter can be helpful if cereal rye is thick.  
  • Ensure sharp double disc openers and good down pressure. 
  • Make sure the seed trench is closed. 
  • Spiked closing wheels and/or cast iron, but not long or curved spikes. 
  • No drag chains. 
  • Residue movers not needed (or recommended).  Want to maximize cover in the row, not remove it.   
  • Emergence is slower compared to conventional till or bare no-till planting conditions.  But, the soybean plants generally catch up as the season progresses.  In some cases, plant height may lag all season, but yields can still be competitive or higher with more pod set on tighter nodes and more seed fill.  Remember, soybeans are adaptive. 
  • Consider walking away for three weeks after planting, don’t judge the stand by plant height in July or August.  Look at number of pods and size in September.  
  • Scout for armyworm and slugs.  Practice Integrated Pest Management. Recent research suggests that neonicotinoid seed treatment can exacerbate slug feeding by killing the slugs’ main predators, like ground beetles. 

  • Work is being done to have a successful crimp ahead of corn, but many challenges have yet to be worked out. A mix of grass and legume cover crops with a low C:N ratio tends to be the approach to success with corn, along with a willingness to plant corn late to allow the cover crop to reach anthesis/full flower. The cover crop must reach this state for adequate termination from roller crimping, and to provide maximum N fixation.
  • Predicting the full flowering date of cereal rye in April would help with adaptive management decision-making. A team of researchers, agronomists, and farmers are currently improving data collection to inform the development of predictive models.
    • Possible ranges based on data from Central to Northern Illinois and Indiana during 2014-2017 growing seasons.
    • You can see that the end of April to early May soybean planting can be accomplished before crimping occurs. If dry spring or no rain after planting this could result in very dry soil and poor emergence.

Join the following two listserves for real-time feedback when researching and implementing this system 

Organic Weed Control

From the New Ag Network's "Organic Weed Control" fact sheet written by Dale Mutch. Weeds are the No. 1 concern for field crop organic farmers and pose important problems for vegetable and fruit organic farmers. This is because weeds can dramatically reduce crop yield if they are not managed and controlled. Specific weeds may also provide alternative hosts for insects and pathogens, as well as interfere with harvest either by interfering with machinery or through crop contamination. Organic farmers must use multiple tactics to manage weeds because they cannot use synthetic herbicides, and existing organically acceptable herbicides are costly and primarily limited to burndown activity. For more information see the “Integrated Weed Management” books in the reference section.

As they say, “Know your enemy.” Organic farmers need to pay close attention to what types of weeds are in their fields and how they grow. Know weed life cycles. Are they annual, perennial or biennial weeds? Will the weeds germinate early or mid-summer? How deep in the soil will the seeds germinate? How much seed will the weed produce? Do weeds reproduce vegetatively via rhizomes or stolons? An additional question specific to perennial crops is: Which weeds are problems at time of establishment versus post crop/planting establishment?

The best line of defense is to build healthy soil. A biologically active and diverse soil will reduce weed populations and help crops grow faster. The faster a crop builds a canopy to fill rows and cover the soil, the less impact weeds will have on the crop. Decreasing weed growth dramatically reduces weed seed production. Healthy soils stimulate weed seed decay and can increase weed seed predation. Healthy soil can be built by using cover crops, choosing good crop rotation, applying compost and other organic soil amendments, maintaining appropriate drainage and reducing compaction. Generally, farmers want to keep weeds out of the field for the first four to six weeks of annual crop growth to maximize crop yield potential.

Here are some of the practices used by organic farmers to reduce weed problems:

  • If early weed species such as common lambsquarters or smartweed begin growing, consider allowing these weeds to germinate, then kill them with tillage and delay the crop planting, allowing the crop to get ahead of the weeds.
  • Increase seeding rates and narrow planting rows to give the desired crop a competitive advantage over weeds.
  • Select varieties that will succeed better under organic farming methods.
  • For perennial fruit and most vegetable crops, consider using mulches to “smother” weeds. These could consist of wood chips, plastic or fabric weed cloth, living mulches or, in some cases, hay or straw.

  • Use tillage as a tool to control weeds. Early tillage for seed bed preparation could be moldboard plowing, chisel plowing, field cultivating, rotovating, offset discing or field cultivation. After planting, try rotary hoeing, cultivating or flaming weeds with heat to control weeds.
  • Pull, clip and remove weeds when the crops cannot be cultivated. If necessary, hire labor. Since weeds are prolific seed producers, removing these larger weeds can have a positive impact on the weed seed bank in the soil.

  1. "Flaming as a Method of Weed Control in Organic Farming Systems." MSU Extension bulletin E-3038. Mutch, D., S.A. Thalmann, T.E. Martin and D.G. Baas. 2008. E. Lansing, Mich.
  2. "Integrated Weed Management: ‘One Year’s Seeding…’” MSU Extension bulletin E-2931. Davis, A., K. Renner, C. Sprague, L. Dyer and D. Mutch. 2005. E. Lansing, Mich. Michigan State University.
  3. “Integrated Weed Management: Fine Tuning the System.” MSU Extension bulletin E-3065. Taylor, E., K. Renner, and C. Sprague. 2008. E. Lansing, Mich. Michigan State University.
  4. Organic Field Crop Handbook.” Second edition. Canadian Organic Growers, Box 6408, Station J, Ottawa, Ontario K2A 3Y6.
  5. ATTRA. “Field Crops.” 800-346-9140.
  6. Organic Weed Control: Cultural and Mechanical Methods.” Howell, M. and K. Martens. Acres. August 2002, Vol. 32, No. 8. 800-355-5313.
  7. Organic Weed Management: Organic Field Crop Production and Marketing.” Burton, M., R. Weisz, A. York and M. Hamilton. North Carolina State University.
  8. Weed Management in Organic Cropping Systems.” Penn State University Extension. Agronomy Facts 64.
  9. SARE. m a. “Steel in the Field: A Farmer’s Guide to Weed Management Tools.”

Organic Disease Management

A certified organic farm can control plant disease by implementing a variety of approaches. Good cultural management is a cornerstone to organic disease control, and includes good sanitation, crop rotation (when possible), keeping plants healthy, and the use of resistant varieties. Fungicides can be used as well, but for organic production, fungicide use is limited to using sulfur, copper, oils and bicarbonates to control plant disease outbreaks. These fungicides have been used for thousands of years, but are not as effective as synthetic fungicides. As a result, organic growers need to spray more often. This can be quite devastating to a farmer’s financial bottom line. As such it is important as an organic farmer to reduce the incidence of disease, maintain resistant varieties of crops/fruits, and build up plant defenses to lower the need for external inputs to control outbreaks. Purdue University has conducted work on disease-resistant varieties of vegetables and fruits, which can be found on a variety of different websites within the College of Agriculture but predominantly in the Departments of Botany and Plant Pathology and Horticulture. A few can be found at the following links.


Oftentimes the most important aspect to dealing with the disease in organic systems is in the cultural practices of cultivating and growing a crop. Maintaining healthy soil creates healthy plants less susceptible to disease. Rotating your crops helps to diminish disease populations from building up. The following link gives you numerous practices to think about to reduce diseases from becoming problems; Managing Scab-Resistant Apples. And although you are not allowed in a certified organic farm to use chemical fungicides, there are some that are considered organic and can be used. The following link does a good job of explaining that the first step to disease management is identifying what you have and then determining what is allowed within the organic certification system; Using Organic Fungicides.  Many PDF files can be found at the following websites that give you more information on how to manage disease in your crops, whether it is an organic or conventional system.

Insect Pest Management

Insects can truly make or break crop systems. Organic farms are home to a more balanced and sustainable community of beneficial insects than conventional ones, and there are quite a few cultural techniques that can improve within-field habitat to encourage natural pest suppression services. Still, herbivorous pests can be devastating, but they can also be managed effectively using Integrated Pest Management (IPM) strategies that promote regular monitoring, and proper pest identification. This will enable thoughtful choices of pest control tools that are the most affordable, specific, effective, and will reduce damage to the insect predator community. We'll provide several resources here to help implement sustainable organic IPM strategies.

Additional Resources

OGRAIN is an educational framework for developing organic grain production in the upper Midwest. Resources include field days, annual intensives, a mentorship program, and more.

Organic Grain Resource and Information Network (OGRAIN)

This manual, published by the University of Minnesota, is intended as a guide for organic and transitioning producers in the Upper Midwest to lower risk in their operations

Risk Management Guide for Organic Producers

OMRI supports organic integrity by developing clear information and guidance about materials so that producers know which products are appropriate for organic operations.

Organic Materials Review Institute

eOrganic is an organic agriculture community with the mission to foster a research and outreach community, engage farmers and ag professionals through trainings and publications, and more.


ATTRA is a program developed and managed by the National Center for Appropriate Technology, which provides information and technical assistance to those involved in sustainable agriculture in the U.S.

Fieldwatch & Driftwatch provides a secure online mapping tool to enhance communications that promote awareness and stewardship activities between crop producers, beekeepers, and pesticide applicators.

Fieldwatch & Driftwatch