Hopping into Spring with Crowning

Welcome to another hop season! We are gearing up for the growing season and first on the to-do list is spring crowning.

As you know, Downy Mildew (DM) is a major concern for us in the Northeast and we must use every tool we have to manage it. DM can overwinter in the plant crown and will emerge with the first shoots–if left unchecked, it can spread and try to increase its foothold in your yard.

“Crowning” is the practice of removing new growth as well as the very top of the hop crown early in the season. Removing new growth without going as deep as the crown is often referred to as “scratching” or “pruning.” Crowning is typically accomplished through mechanical means, but removing shoots by other means such as chemical burndown or flaming is also known to be effective, but does not affect inoculum living in the crown.

Crowning reduces the amount of plant material that is above ground and available for DM spores to land on during wet spring conditions that are ideal for infection. Cutting the plant back is an advantage for managing disease; however, it also reduces the time the plant has to grow to the top of the trellis, which may likely reduce yield. This is why the timing of crowning is so critical – we want to crown early enough that the plant has ample time to grow back.

Our team has been conducting trials on timing at our hopyard at Borderview Research Farm in Alburgh, Vermont. So far, our trial results suggest that  crowning in mid to late April has yielded the best results. For example, in 2015, our early crowning date (23-April) yielded better than the late crowning date (13-May) AND performed better than control plots that were not crowned at all. The later date in May had a larger reduction in disease, but suffered in yield. So, it seems like early crowning is the sweet spot between good yield and disease management. See the full results of our crowning trial here: 2015 Hop Crowning Trial.

We think that crowning early may have the added benefit of allowing the soil to warm quicker by removing excess material covering the soil and generally turning/aerating the soil a bit. We mulch our hop yard, and the mulch can act as an insulating layer, keeping the hops cooler than the air temperature in spring. The high yields from our early-crowned hops may be partly due to warmer soil temperatures.

Walk-behind trimmer outfitted with crowning blade.
Walk-behind trimmer outfitted with crowning blade. Photo credit: UVM Extension Northwest Crops & Soils Program.

Crowning Equipment Options

Want to know what equipment to use? There are several options!

For small acreages, if you are on a budget and/or would like to test crowning in a small section of your yard this year, it might make sense to use something similar to a walk-behind trimmer. We currently use this unit for crowning. It has been modified with a metal blade with teeth to better cut plant growth. One challenge to using this piece of equipment, other than time, is consistency. Where other implements cover the whole bed at a constant height, this trimmer is used to target the specific plants as their shoots appear from the ground, and relies on the operator to maintain consistent depth.

Our team is currently shopping for a tractor-mounted crowner. The unit has sharp discs that prune back growth while the rotation of the discs spreads soil and mulch above the blades. This tool may be a good fit for those who hill their hops and need to cut the bed height down at the beginning of the season.

Crowner by John I Haas. Photo credit: UVM Extension Northwest Crops & Soils Program.
Crowner by John I Haas. Photo credit: UVM Extension Northwest Crops & Soils Program.

Other implements have tines that cultivate the soil surface and remove growth (like the John I. Haas crowner pictured on right). What ever equipment and technique you choose to use, crowning is an important practice for disease management, and also has a large effect on the growth timing of your plants. Remember that you want those plants at the top of your trellis by the beginning of July, so your crowning and training should be built around achieving that.

Stay tuned for future posts on training. Until then, keep calm and hop on!

Don’t miss out on attending our Vermont Annual Hop Conference!

IMG_0979WHEN:  Friday, February 19, 2016

TIME:  9:00 a.m. to 4:00 p.m.  Registration starting at 8:15 a.m.

PLACE:  The Hampton Inn Vermont Event Center at 42 Lower Mountain View Drive, Colchester, VT 05446

Join us to hear information about hop agronomy and fertility management, hop growing challenges in England (including diseases), scaling-up production, updated hop research, efficient management and trellis construction, training of your hop yard, and maintaining hop quality during and post-harvest.  View our detailed agenda.

Register today for the 2016 Annual Hop Conference!  And if you are unable to join us in person, choose to watch it via a live broadcast.

NOTE:  When arriving at The Hampton Inn, do not use the Front Entrance.  Follow the signs to the Conference Entrance (2nd driveway on right).  Then as you go around the building, you will see Entrance C to the Conference Center.  Please use this entrance.

Mark Your Calendars: NeHA Annual Meeting at Cornell Hops Conference, 12/5/15

The annual conference of the Northeast Hops Alliance will be held in conjunction with Cornell University’s Annual Hops Conference, scheduled for December 5, 2015 from 8 a.m. to 5 p.m. at Morrisville State College in Morrisville, New York.

This is a great opportunity to network with brewers, educators, and hop growers, as well as to learn the latest research on hop production. This year, speaker’s will include: Tim Weigle, Dave Combs, Dr. Rob Sirrine, Jessica Lyga, Rich Michaels, Dr. Paul Matthews, Kevin Riel, Dr. Chris Nyberg, Dr. Jason Townsend, Steve Miller, Dr. David Gadoury, as well as UVM’s own Dr. Lily Calderwood and Chris Callahan.

Registration is $75 for NeHA members and $85 for non-members–please plan to register by November 23. More information can be found in the October 2015 edition of the NeHA newsletter at: and/or at:

Hop Harvesting Field Day, September 11, 2015

2014 harvest at Borderview Research Farm.
2014 harvest at Borderview Research Farm.

Please join us for a informal Hop Harvesting Field Day!

We will hold this informal event on Friday, September 11, 2015 from 1:00 p.m. to 3:00 p.m. at the Borderview Research Farm, 146 Line Road, Alburgh, Vermont.

Come learn about and share your experiences with harvesting and drying hops.  We will demonstrate how to test dry matter of your hops, show harvesting and drying equipment, and share our most recent research findings on hops.  Come with questions for discussion!

We will be using a hops harvester from

There is no cost for this event, but please R.S.V.P. by Wednesday, September 9, by emailing  Please provide full name, email address, phone number, and how many will be attending.

Hop Cone Disease Symptoms

Dark brown bracts are a symptom of hop downy mildew.
Dark brown bracts are a symptom of hop downy mildew.

Why are my hop cones black?

Harvest is approaching quickly and for some may be well underway! This season’s wet conditions have resulted in high disease pressure on the hop plants. These diseases are now starting to show up on the cones of the plant. At this time, we have identified primary fungi downy mildew and Alternaria on cones from the UVM hop yard. Photos and description of the symptoms are below.

At this point it is unclear what, if any, yield or quality damage will result from disease infested cones. For now, we can say that downy mildew and Alternaria are causing aesthetic damage to the cones that are infected.

What should you do?

Hop cone quality will decrease the longer hop bines with downy mildew are left out in the yard because it quickly dries out the cones. If you are starting to see downy mildew damage on your cones, you may consider harvesting early to reduce continued infection and overall quality loss.

If a plant has cones that are completely black, they likely have very poor quality and are not worth harvesting. Remove the severely infected plant material from the hop yard. For further reading and pictures please see “Field Guide for Integrated Pest Management in Hops” (Gent et al. 2009).

Reddish-brown brushing is a symptom of alternaria. Photo credit: S. J. Pethybridge
Reddish-brown brushing is a symptom of Alternaria. Photo: Gent et. al. 2009.






Getting Ready for Harvest: Smell, Touch, Hear, & Measure

Timing is critical to harvesting high quality Northeastern hops, as is paying close attention to drying, packaging, and storing the harvest.

Our hops at the Alburgh research farm are not quite ready to harvest yet. We predict that the harvest of early maturing varieties will begin at the end of next week (the week of August 24, 2015). We use dry matter content to make the final decision on harvest timing, but there are flavor-related strategies that are quick and can be a good place to start.

Alpha acids develop before beta acids in hop cones. Studies of Northeastern hops indicate that we should allow cone chemistry to develop further than has been traditionally recommended in order to let these beta acids develop. This means leaving hops on the bine for a slightly longer period of time when possible.

At this time of year, it is important to walk through your hop yard to evaluate hops. Do a sensory test that includes smell, touch, and sound. Hops that are not quite ready smell “green” like hay or grass, while over-ripe hops smell like onions, sulfur, and garlic. In general, you should be able to smell hops from a couple feet away from a plant when they are ready. One Pacific Northwestern grower said he knows when his hops are ready because a cone will sound like a baby rattle when shaken. This goes to show that every region and every farm has their own group of specific sensory characteristics to determine hop readiness. If you have a microscope, you can also take a look at the lupulin glands. Lupulin glands that are ready should be shiny, golden, and have an acorn shape.

Getting ready to pop some hops in the dehydrator.
Getting ready to pop some hops in the dehydrator.

Once you think that your hops are ready, it is time to measure hop cone dry matter content. Dry matter is the deciding factor that we use to determine when hops are ready to be harvested. We harvest at 23% to 27% dry matter. It is known that different varieties can have different optimal harvest dry matters within (or just outside) this range. We highly recommend taking notes on your harvest dry matter and how your crop turns out so that you can make small changes if need be.

To test dry matter: Take a 50 gram sample of wet cones from individual varieties. Make sure that a representative sample is taken from the yard at 10 to 12 feet above the ground. Weigh each wet cone sample. Place cones in a food dehydrator at medium heat or in a microwave. When you think they are dry, take a cone out. Split it open. Is it still wet? Weigh the dry cones and calculate dry matter or moisture content. Our UVM Extension Hop Harvest Moisture Calculator will calculate dry matter for you from wet and dry weights. See our website for more information on dry matter calculation, including our Hops Harvest Moisture Determination factsheet.

Note: in hot, dry conditions, cones can mature and dry very quickly. In hot weather, dry matter levels can change rapidly, so pay close attention over these warm summer days! For an academic journal on hop maturation, see “The Development of brewing quality characteristics in hops during maturation,” by M. Murphey and G. Probasco, (1996) Tech. Qrtly. Master Brewers Assoc. of the Americas, 33(3) 149-159.

If you are noticing black or browning cones, stay tuned for our next blog post on cone diseases.

Hops Production course at VTC

Vermont Technical College asked if we would please share the information on a Hops course they are offering on August 10-11, 2015.  Following is the course information, as well as their contact information.

Hops Production. August 10-11, 2015. $200.

Description: Two day introductory course in small scale hop farming in the Northeast. Day one will be in the classroom learning hop biology, diseases, and brewing characteristics. Day two will be at Addison Hop Farm in Addison, VT to explore a functioning hopyard during the harvest season.

Thank you for your time! Look forward to hearing from you.hopplantwithhops


Rachel Arsenault  |  Marketing & Administrative Assistant

Institute for Applied Agriculture & Food Systems

802.370.9898  |   802.728.1677  |

PO Box 500 | Randolph Center, VT 05061


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Biopesticides: A Natural Alternative

Gram stain of Bacillus thuringiensis under 1000 X magnification. Image credit: Dr. Sahay, Wikimedia Commons

Biological pesticides, or biopesticides, are pest management tools derived from animals, plants, bacteria, and/or naturally occurring minerals. Many common biopesticides uses microorganisms like entomopathogenic bacteria, fungi, nematodes or viruses as their active ingredients. The most widely used microbial pesticides are derived from Bacillus thuringiensis, or Bt. Each strain of this soil bacterium produces a different mix of toxic crystalline proteins; as a result their activity is restricted to certain groups of insects. For example, a relatively new bioinsecticide derived from Bacillus thuringiensis galleriae (Btg), is only toxic to certain beetles, including Japanese beetle adults and larvae!

According to the EPA, biopesticides are generally less toxic than conventional pesticides, often only affect target pests (and closely related organisms), are usually effective at low concentrations and tend to decompose quickly reducing exposures and potentially avoiding the pollution problems associated with conventional pesticides. Biopesticides have long been used as an effective pest management strategy for organic crop production. However, their use has increasingly been recommended as part of Integrated Pest Management programs to reduce the use of conventional pesticides while maintaining high yields.

Biopesticides are coming on the market at breakneck pace; because of this, little is known about their efficacy, particularly on hops. At our hopyard, we are currently evaluating several biofungicides to determine their efficacy at managing downy mildew in hops, and we have been experimenting with bioherbicides for weed management.

As with all pesticide use, carefully follow all label directions to use biopesticides safely and effectively. A note of caution for certified organic growers: even though biopesticides are derived from natural sources does not mean that all are approved for use in organic production. Always check with your certifier before adopting new practices or using new materials.

With temperatures in the 90s this week, keep up the irrigation and be on the lookout for two-spotted spider mites. And remember, keep calm and hop on…

Come On Over to Our Hopyard, 7/23

Borderview Research Farm
Borderview Research Farm

Join us this Thursday, July 23, 2015 from 10 a.m. to 3:30 p.m. for our annual Crops and Soils Field Day at the Borderview Research Farm in Alburgh.

The day will include tour stops to our hopyard where we will discuss critical hop insect and disease pests and our research–including new trials on bio fungicides–to discover effective management strategies for our region.

You will be able to look at hop equipment, including driers, balers, and harvesters. See our trellis and irrigation systems and learn about fertigating. The afternoon will also include a research update on downy mildew and weed management.

Registration, which includes lunch, is $10 for farmers; $25 for others. To register online and for more information, visit

3 Things that Matter in Pest Scouting: Location, Location, Location

Hop aphids.
Hop aphids.

“There are three things that matter in property: location, location, location.” We have found that location also matters in growing hops, particularly this spring. Southern Vermont has been exceptionally dry for long periods, while northern parts of our region have been soggy, to say the least.

The cool, wet conditions that we’ve been experiencing in the north typically favor hop aphids, however, we haven’t been seeing many aphids in Vermont hopyards this season. Perhaps they have been slow to move from their alternate host, woody plants in the genus Prunus (cherries, other stone fruits, etc.). Unfortunately, these conditions are quite favorable for downy mildew,  so diligent downy mildew management has been a must.

Meanwhile, the relative warmth in southern portions of our region, combined with the early arrival of potato leafhoppers this year, means we are starting to see second generation leafhopper nymphs scuttling across the undersides of hop leaves. This also helps explain the early appearance of two-spotted spider mites as well as spider mite destroyers, their arch nemesis (and our friend). The aptly named spider mite destroyers (ladybugs that specialize on spider mites) can be very helpful when managing spider mites as the season progresses.

Japanese Beetle
Japanese Beetle.

The old saying “knee-high by the 4th of July” may be more commonly used when talking about corn, but be on the lookout for our most patriotic of pests: Japanese beetles. Come July 4th, some of us begin to feel like we are knee-high in Japanese beetles.

Just remember, keep calm and hop on…

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