An Experiment on the Effectiveness of Irrigation and Cover Cropping to Produce Sustainable Hops in Maine

Project Overview

Project Type: Farmer
Funds awarded in 2011: $10,197.00
Projected End Date: 12/31/2012
Region: Northeast
State: Maine
Project Leader:
Dr. Jason Johnston
Aroostook Hops
Krista Delahunty
Aroostook Hops


  • Agronomic: hops


  • Crop Production: conservation tillage
  • Education and Training: display, extension, farmer to farmer, networking
  • Farm Business Management: budgets/cost and returns
  • Production Systems: organic agriculture
  • Soil Management: green manures, organic matter, soil analysis, soil quality/health

    Proposal summary:

    Commercial hops production has been largely absent in the northeastern U.S. since the 1920’s, even though there is significant craft and microbrewery beer production here. A sustainable beer production requires that brewing ingredients be produced closer to the source of production and consumption. Throughout the northeastern U.S. a variety of growers have raised hops, which have been used by brewers. However, competing with high volume Pacific-Northwest producers is problematic due to their economies of scale, efficiency, and longstanding business relations. Nonetheless, sustainable hops production relies on minimal travel distance to brewing facilities and production in the Northeast may be bolstered by the local food movement. While locally sourced hops producers could eliminate 2,000 miles of transportation, many of these growers confront issues related to economies of scale. Thus, the main problem is how do small-acreage hops farmers produce a profitable hops crop? Northwest hops production relies on expensive equipment for irrigation, cultivation, and harvesting - most of which cannot be easily supported by small acreage Northeast hops farmers. Furthermore, the arid, hot growing conditions of the Northwest are different from the milder, humid conditions of the Northeast. Thus, hops cultivation practices recommended for the Northwest cannot be simply applied to the Northeast due to these differences in climate and scale. Two main problems exist for Northeast hops farmers: 1) what is the most effective way to control weeds with the least input of labor, and 2) does increased yield from irrigation justify its expense?

    Project objectives from proposal:

    We have spent the last two years researching and informally experimenting with methods to improve soil nutrients, reduce labor associated with weed control, and improve other aspects of small-scale hops cultivation. Since we aim for commercial viability we plan to manipulate factors that we expect to significantly increase yield or reduce labor. We have and will continue to provide a standard set of growing conditions, as follows.

    We have established 1.5 m wide rows to maintain reduced competition for hops roots and rhizomes; we maintain this by shallow tilling several times per season. We will continue to till one strip on either side of the row, but stay 25 cm away from the row center to avoid tilling the current year’s growth. We have supplemented all hops rows with composted cow manure (topdressed in spring, 2010 with 6 cm deep by 1 m wide and tilled during autumn, 2010). In spring, 2011 we will add bloodmeal to increase nitrogen (based on low soil N in Fall, 2010). The between-row space (3 m) is currently grass and weeds, and is controlled by mowing. We plan to have this tilled in early spring, 2011, and planted with a mix of perennial leguminous and flowering plants to increase soil nitrogen, reduce compaction, and attract beneficial insect predators (citation). Hops are strung in mid to late May using coir twine on 15’ trellising consisting of 4X4” center posts, 6X6” end posts at an angle, and 3/8” aircraft cable. We will survey all plants weekly for insects, and use manual methods to remove them unless an infestation requires us to use an organic-approved insecticide. During 2009, we did not have problems with aphids or spider mites, but we did have a moderate problem with a Lepidoptera larvae, likely Polygonia interrogationis, which we controlled by picking. We will monitor for other problems, such as mildews, and consult our technical advisor, Dr. Steven Johnson, if we suspect any plant infections.

    Aside from the standard growing conditions described above we will manipulate two factors that we anticipate to have the greatest impact on increasing yield or reducing labor. We will use two cover methods to examine weed suppression effectiveness within the 90 cm row center: straw and summer alfalfa. Straw will be applied in the space between plants, but not right up to the plant so as not to promote mold or fungal growth. Straw that was used for winter mulching will be removed from the crown in early spring, and additional straw will be added, if necessary, to achieve 8 cm of straw. Using the straw for both winter and growing season mulching is one way that time and labor costs can be saved. Winter mulching is imperative to avoid winterkill; while we have not experienced winterkill, 2009-2010 was the mildest winter on record. Previous SARE-funded farmers and others in New York have demonstrated the importance of winter mulching. Summer alfalfa will be planted as the other cover. During 2009 we found that cowpeas were a fairly effective weed competitor if planted densely, and we had planned to use this same cover crop for 2010. We had initially chosen cowpeas because it was guaranteed to be winterkilled and we thought it would interfere less with hops growth than other common nitrogen fixers, e.g. clover. Other hops farmers we communicated with have reported that the fibrous roots of clover reduced hops yield due to competition. We will use summer alfalfa because it is winterkilled, reduces soil compaction, is a good nitrogen fixer, and grows to only a moderate height. We will plant alfalfa (with a small percentage of oats) in mid-May, in 1 m wide strips around the hops plants, except for the 10 cm around the hops crown.

    Irrigation will be the second manipulated factor. Alternating rows will be irrigated or non-irrigated by drip emitter irrigation. Irrigation will be conducted as needed, at least twice weekly, and in consultation with our technical advisor. We will also measure weekly precipitation at our farm in order to assess the value of irrigation versus ambient precipitation.

    See HopyardPlot.xlsx for a map of our varieties and treatments. Given that we have four varieties and three ages we also plan to examine the impacts of irrigation and cover type for each of these combinations (we don’t have all combinations, e.g. for Willamette we will only test alfalfa as cover, since we have only 28 plants). Separate statistical models will be analyzed for each age X variety combination. This will provide us the ability to make recommendations on how irrigation and cover type may increase yield on mature (3-year old) hops plants versus 2-year old plants that typically produce lower yield. Improving yield for 2-year old plants would bring earlier profits to establishing farmers. By testing plants from rhizomes planted in spring 2011 we will be able to determine how our treatments affect their growth, and hence their potential second year yield. Since these are expected to produce few cones, we will measure height in mid-August as our dependent variable.

    Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the view of the U.S. Department of Agriculture or SARE.