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Additional Support


To help the US hemp industry thrive, we believe it is vital to ensure producers have resources at their finger tips to manage a successful and profitable hemp crop. We offer hemp producers industry leading agronomic support based on our expertise from 8 years of breeding, researching, and producing hemp. This portal includes our most up-to-date recommendations based on NWG variety performance.

Personalized agronomic support is available for qualified NWG growers. Give us a shout, and we’ll get you connected with our agronomist.

Note: Agronomic recommendations are based on NWG variety production; we cannot advise on other hemp genetics. See University Data for more information on variety performance.

Recommendations are based on data from growing on 30″ rows with an average planting density of 8-10 lbs/acre. With early planting and good weed management varieties can be grown on 7″ rows at a planting density of ~16 lbs/acre and achieve higher yields. Densities should be calculated according to plants/acre. Recommended plants per acre and agronomic practices will vary depending on which product is primary: Stalk, Grain, or CBD.

Agronomics are based on our experience and data through the 2021 growing season, updates will be made by November 2022.

The contents of this customer page and any data are confidential and are intended solely for customer use. The information may also be legally privileged. Any reproduction or dissemination of the contents of this page is strictly prohibited. 

2021 Key Learnings

  • Plant early to help beat summer annual weeds.
  • Avoid areas prone to standing water.
  • In-row density helps with weed control.
  • Narrow row spacing results in higher grain yields.
  • Narrow row spacing results in shorter plants.
  • Do not harvest too wet.
  • Hemp threshes harder and is more easily damaged.
  • Hemp grain heats up and spoils quickly.
  • Have adequate aeration and drying facilities ready to go after harvest.
  • Avoid dual-rotor combines – New Holland and Claas/Lexion.


Hemp Field Planting in Iowa NWG 2730

When to seed

Depending on your region, hemp seed can be sowed successfully from April to June on a variety of row spacings using a traditional grain drill or planter. Plant early to help combat weed pressure and minimize the need for cultivation. Plant into moisture or have irrigation available to establish a good stand.

How to Seed

Plant into a weed-free seedbed as soon after the last tillage or burndown herbicide application as possible. This gives your hemp crop the best competitive advantage against weeds. At the time, no synthetic herbicides are labeled for hemp, so weeds must be controlled through cultivation and/or early establishment of crop canopy.

Row spacing is a major decision in weed control.

  • Planter drilling hemp seed.Row spacing of 6″ to 15″ will produce thinner stalks preferable for bast production.
    • Tighter row spacing requires:
      1. Good pre-plant weed control
      2. Inputs to maximize stand establishment to outcompete weeds
        Note: Cultivation is likely not an option for tighter row spacing.
  • Row spacing >20″ allows in-row cultivation for weed control.
  • Plant at a depth of 0.5″ or less into a firm (>45° F) seedbed with good moisture.
    • Soil should remain moist until adequate stand is established, normally 7-14 days after seeding.

Note on Soil Condition: Hemp will germinate well at temperatures lower than most summer annual weed species. If you are planting in soils prone to crusting take action to mitigate crusting early.

How Much Seed

Hemp Seed Planting

Recommended seeding rates depend on the row spacing possible for your farm. If you have a field with low weed pressure (e.g. following alfalfa), tighter row spacing will translate to generally higher grain yields and a shorter crop. Wider row spacing allows for cultivation.

General seed spacing recommendations:

  • 7.5″ rows: 1.3″ in-row seed spacing (~20 lbs/ac)
  • 15″ rows: 0.9″ in-row seed spacing (~15 lbs/ac)
  • 30″ rows: 0.7″ in-row seed spacing (~10 lbs/ac)

Effect of Row Spacing

Row Spacing Impact on Grain Yield New West Genetics Internal Research 2021

Figure 1. Grain yield from a replicated small plot field trial averaged across NWG varieties in one location in one year.

Row Spacing Impact on Hemp Plant Height NWG Internal Research

Figure 2. Plant heights from a replicated small plot field trial averaged across NWG varieties in one location in one year.


Center pivot irrigation on NWG plot trial

Center pivot irrigation on NWG hemp variety plot trial in Northern Colorado.

While hemp requires less water than other typical row crops, higher yields will be supported by strategic irrigation. The rule of thumb is water early and often to support uniform seed germination and prevent soil crusting.

Critical timepoints:

  • Immediately after planting to facilitate uniform emergence
    • Regular irrigation starting immediately after planting supports stand uniformity.
    • Well-timed and well-managed irrigation can soften soil crusting and promote good establishment.
    • Note: excessive moisture after planting can severely impact crop establishment. Saturated soil conditions should be avoided.
  • A minimum of 12″ per season is generally recommended
    • This is highly dependent upon the transpirational demand (e.g. relative humidity) of the production environment.


Hemp generally requires less fertilizer inputs than other common row crops, but should be fertilized similar to a winter wheat crop. It’s best to test your field’s soil fertility before applying fertilizer, as too much fertilizer can result in a crop that is too tall for mechanical harvest. Use caution with seed-placed fertilizer, hemp is sensitive to salt and stand loss can occur.

N: 60-100 lbs/ac of available N (more for grain crops in high-yield environments)
P: 50 lbs/ac of available P (apply if less than “high” on soil test)
K: 50-60 lbs/ac (apply if less than “high” on soil test)

Sidedress Fertilizer Applied to Hemp Seed Production Field

Sidedress Fertilizer Applied to Hemp Seed Production Field


Plan for weed control to maximize yield potential and quality. Weed pressure will impact harvest, and for fiber production foreign material impacts processing. Your primary defense against weeds is effective pre-plant weed management and early establishment of a good plant stand. Once the crop forms a canopy it outcompetes most weed species.

  • Cultivate at least 2x pre-canopy to control weeds
    • First – during early development (as early as possible), run cultivator at a slow speed.
    • Additional passes – run at higher speed to develop ridges at the base of the plants to cover weed seedlings.
  • Hand weeding may be necessary to control areas of heavy weed pressure.
  • Do not apply any herbicide unless it is labeled for hemp.

New West Genetics Mechanical Hemp Cultivation


For a multi-purpose hemp crop, prioritize harvest for your highest value product first.

Grain | Cannabinoids | Fiber

Truckload of clean, dry hemp grain

Primary target is grain:

Separate seed from biomass (flower and fiber) during or after harvest, and harvest with an appropriately set combine. We provide specific settings for several makes and models, but most modern combines are well-equipped to harvest a hemp grain crop. Minimize the amount of stalk entering the combine by harvesting just below the cola. 

Grain hemp is most often direct-harvested when the plant is slightly green to minimize stem fiber wrapping. It can be threshed anywhere from 10-20% grain moisture, but harvested grain should be dried to less than 10% moisture immediately. Reduce auger speeds, run augers full, and use larger diameter augers when moving hemp grain. Pneumatic or belt conveyors are preferred to augers.

When to harvest

Hemp Seed Harvest NWG 2463

Hemp Seed Harvest NWG 2463

  • The crop reaches maturity after 100-120 days.
  • 70-80% of the seeds are ripe.
    • Drying bracts and seed exposure are a good indicator that the crop is ready to harvest
  • Seed moisture is <20%
  • Fall frosts assist in gradual drying, but a killing frost will initiate a rapid dry down. Combine within days of a killing frost.
  • Direct-harvest is recommended, and a draper header is preferred over an auger header. Draper headers give more room for the hemp colas to lay down and feed evenly into the combine.
  • Swathing or windrows are also an option in geographies which are favorable to field drying (i.e. Colorado).

Combining Hemp

ABOUND Hemp Harvest with a combine

Most modern single rotor and conventional combines can effectively harvest hemp grain. Combine settings vary by model and conditions, but are generally similar to wheat or canola. Set the combine to thresh as gently as possible to minimize cracked seed. Adjust combine settings on the go as conditions change, but focus on minimizing stalk material entering the combine and thresh colas as gently as possible to remove the seed. This maximizes seed quality and minimizes the amount of green material entering the sieve area. Wetter colas are more difficult to thresh than dryer colas and the wetter chaff is more difficult to effectively separate from seed with fans and sieves to achieve a clean sample.

Twin rotor combines like New Holland and hybrid rotor combines like Class/Lexion are not recommended due to fiber wrapping on smaller diameter rotors.

Hemp Harvest

Hemp seed is difficult to see on the ground compared to other crops. Spending time walking ahead of and behind the combine to understand and quantify sources of grain loss (pre-harvest shattering, header loss, separator loss and cleaning loss) are well worth the time.

General settings for first time hemp harvest:

  • Rotor or cylinder 450-600 rpm
  • Concave – small grain, medium wire and round bar concaves have been used successfully to harvest hemp.
    • Concave clearance should be set as wide as possible while still threshing colas: 25-40 mm.
    • Start open and tighten concaves until all seed is removed from colas but the straw left behind the combine is largely intact.
    • Overthreshing results in grain damage, creates more fine material entering the cleaning system, uses more power and can decorticate stems, and increases the likelihood of wrapping.
  • Sieves – Set similarly to wheat or canola as a starting point. A goal should be not to send too much material back through the tailings system, potentially doing damage to seed.
  • Fan – hemp is less dense than other crops at 44 lbs/bushel, so fan speed generally needs to be adjusted down. 750 rpm is a good starting point and can be adjusted until the sample is clean and loss off the sieves is eliminated.

Combine settings by model

These settings are recommendations and not the rule, changing crop conditions mean it is important to monitor the progress and adjust as necessary.

  • Case IH 8520

    • Sped up rotor discharge chopper knives and engaged to 1 notch to prevent wrapping.
    • Disengage straw chopper, ran chaff spreader.
    • Concave – medium wire – 28 – Likely could have been open further.
    • Fan 800 rpm
    • Rotor 550 rpm
    • Pre sieve 8
    • Top sieve (chaffer) 10
    • Bottom sieve 11
    • Rotor vanes – fast
    • Air bar on 40 ft Gerringhoff draper was valuable to prevent header loss.
  • Gleaner S78

    • Hemp settings included in book
    • Concave – 0.4″ – Likely could have been opened further.
    • Fan opening – 3-6
    • Top sieve (chaffer) – 0.625″
    • Bottom sieve – 0.313″
    • Chopper speed – fast
  • Lexion 760 – not recommended due to rotor wrapping

    • Concave – small grain – 24mm
    • Fan – 1100 rpm – wetter colas require higher fan speed.
    • Cylinder – 640rpm
    • Rotors – 650 rpm
    • Top sieve (chaffer) 7
    • Bottom sieve 4

Other considerations

Disable the straw chopper and windrow the straw. Every combine is different and through inspection within the first acre is recommended to find potential problem areas.

Silage chopping is not recommended as it causes seed damage.

Drying and Cleaning

Hemp Grain Bins

Post grain harvest, rapidly dry harvested grain. This may require heated air depending on environmental conditions; higher grain moisture at harvest requires a more expedited drying process.

Drying can be done in the field in windrows, in an arid climate, or using industrial drying methods. Post-harvest drying to stable moisture content should be done soon after harvest.

  • Drying equipment should be appropriate for the size of hemp seed.
  • Seed drying for direct harvest should start within 2 hours of harvest.
    • If sample contains excessive amounts of leaf and stem matter, screening prior to drying will improve the drying time and help prevent spoilage
  • Seed should be dried to less than 10% moisture
  • Air temperature in grain should not exceed 95 F

Ensure product matches processor or contract specifications before shipping. Seed processors may require that steps and other large material be screened out of seed prior to shipping.

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Hemp Cola

This area of hemp production agronomy has the lowest level of optimization – many different approaches are being explored. This is due to the nascency of the CBD industry, following legalization of hemp production. Many of the agronomic practices for flower production are similar to grain production – refer back to the previous section for topics such as planting date, fertility and weed management.

Harvest Timing

CBD concentration tends to increase with the time the crop is in the field. Samples can be taken as harvest approaches to judge the crop’s readiness. Harvest Recommendations for grain are also a guide for flower harvest – when approximately 70% of female bracts are open showing mature seed the crop is ready for harvest.

Harvest Methods

Many different harvest approaches have been used for cannabinoids from hand harvest to fully mechanized. With mechanized harvest of ABOUND varieties, harvest is similar to collecting chaff and grain at the same time. The primary consideration with flower harvest is to minimize handling and loss of trichomes throughout the process as much as possible.

The following is a brief overview of some mechanized harvest options available currently:

  • Direct Harvest – plants stand in field until maturity. Grain is approximately 15-20% moisture, flower is approximately 70% moisture which helps reduce trichome losses but requires drying. In wet conditions hemp will dry faster standing than in a windrow.
  • Windrow & Pickup – plants are cut and windrowed at maturity and left to dry in the field before being picked up and threshed. Flower moisture rapidly decreases and reduces the need for drying but is more prone to trichome loss. This method is only suitable for arid environments and more research is needed on ideal moisture levels for threshing.

Equipment Options

  • Combine – the preferred method for harvesting multipurpose ABOUND varieties. Cutting and threshing are the same as grain hemp, but the separator is modified to collect the flower as well as grain.
  • FarmMax Interceptor: modifies John Deere S-series combines to separate grain, flower, and stalk on the combine and eliminates the need for post-harvest separation.

Farmer modified combines

Exist in different forms but the general changes are to disable the cleaning fan to allow chaff to be carried to the grain tank with the grain. Some modification of clean grain elevator and grain tank cross-augers may be necessary and post-harvest separation is required.

  • Forage Harvester – Forage harvesters are capable of harvesting hemp biomass. They are not recommended for ABOUND varieties unless grain is not an end market product.
    • New Holland Coppice header – the Coppice header was originally designed for biomass crops such as willow but has recently been used for harvest of hemp (generally feminized CBD production)
  • Rotary heads are commonly used to harvest hemp biomass. An effort should be made to cut as high as possible to minimize the amount of stalk material chopped, diluting cannabinoid content.
  • Headers – whether a combine or forage harvester is used, header choice is an important consideration.
    • Draper – the crop flow is smooth and the cutting bar can be raised to minimize the amount of stalk material ingested.
    • Stripper header – a rotating drum with fingers picks the seed and flower off the cola to be threshed, leaving the stalk behind. The drum is prone to wrapping and sending decorticated fibers through the harvest equipment.
  • Hemp Harvest Works SuperCleanCut – similar to an all-crop header but without the auger. The snoots help raise leaning hemp plants that could be unharvestable with a conventional draper.


Flower Harvest for Efficiency

First, as with harvesting any product, the method must maximize harvest of biomass per unit area harvested. Second, it must minimize loss of trichomes which contain the highest cannabinoid concentrations (See FAQs: What do we know about cannabinoids?). Trichomes are small and fragile so their loss during harvest is a legitimate concern. Finally, the method must incorporate a step for effectively sorting seed from flower. Hemp seeds have no cannabinoids so if they are present in the flower, the cannabinoid content of the seed/flower mixture will decrease. The following are brief descriptions of the methods we have reviewed. NWG does not endorse any of these methods (yet!) We will continue to update this page with our own data as we complete our experiments.

  1. Head or whole plant harvest: the principle here is similar to straight cutting grain except that rather than threshing the head, it is harvested into a truck for indoor drying and threshing. By threshing indoors, more control can be applied to trichome loss by collection with vacuum system.
    a. A video of a head harvesting system: Watch Video
    b. A video of a whole-plant harvesting system: Watch Video
  2. Harvest with a combine: this will be similar to grain harvest except that the combine settings are modified. The specific settings are not well-established but the main changes include lowering fan speeds and removing sieves with the intent to minimize loss of product other than the stalk. In this case the flower or flower/seed bulk is augered into the grain bin and then moved indoors for drying and processing. The crop can be windrowed in dry climates to expedite drying but care must be taken to harvest the crop before it becomes too dry in order to minimize trichome loss.
    a. A video of flower harvest with a combine: Watch Video
  3. Stripper header: a stripper header is not a common implement on US farms but it has some practical benefits for harvesting a hemp field. It operates just as the name would imply, the header strips the flower (and grain if present) leaving the stalk remaining in the field.
    a. A video showing a stripper header harvesting wheat: Watch Video
    b. A brief video showing what a field might look like after harvest with a stripper header: Watch Video
  4. Silage bags: This approach is built upon the practice of wet preservation commonly used in fodder production. In short, a forage harvester is used to chop and collect the entirety of the hemp crop. This means that the stalk, stems, the leaves, the flower and any seed that may be present are all harvested. This is expected to lower the cannabinoid percentage considerably since stalks, stems, leaves and seeds are considerably lower in cannabinoid content than the flower. The chopped, wet biomass is then placed into silage bags and the air is removed. What is unclear is the quality of the final product. Watch Video

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Primary Target is Stalk/Fiber

New West Genetics does not currently have recommendations for the best methods for fiber harvest. Contact our agronomy team for specific questions.


We believe dioecious cultivars optimized for production are the only economically feasible approach to scaling production of hemp. It is based on the power of seed multiplication that all large-acreage commodity crops have utilized to create planting seed cost effectively. We expect our agronomic recommendations will change as management methods continue to adjust to improve yield and new inputs and controls are labeled for use on hemp.  Regardless of methods, NWG continues to breed high quality, cutting edge hemp seed genetics that provide the farmers with a low-risk, high value, profitable hemp crop.

Still have questions? Is there something we missed? Reach out to someone on the Agronomy team: