Effectiveness of wet spent brewer's grains as mulch in mixed vegetable production

Project Overview

Project Type: Farmer
Funds awarded in 2012: $6,989.00
Projected End Date: 12/31/2015
Region: Northeast
State: New York
Project Leader:
Regina Dlugokencky
Seedsower Farm

Annual Reports


  • Vegetables: broccoli, onions


  • Crop Production: conservation tillage
  • Education and Training: on-farm/ranch research
  • Pest Management: mulching - vegetative
  • Production Systems: organic agriculture
  • Soil Management: organic matter, soil analysis, nutrient mineralization, soil chemistry, soil quality/health

    Proposal summary:

    Organic vegetable production prohibits using many forms of weed control afforded to the conventional grower. Organic growers are limited to hand weeding, cultivation, and mulching to keep weed pressure to a minimum. Hand weeding is time consuming and thus labor costs are high. Cultivation is limited in long-term effectiveness. Mulching material for Long Island (NY) farmers is an expensive option since cereal farming is not done on Long Island. With the establishment of seven new Microbreweries on Long Island, Spent Brewer’s Grains (SBG), a byproduct in the brewing process, are becoming more abundantly available. A Microbrewer brewing a single seven barrel batch (217 gallons) of beer, will consistently produce a large amount (~220 lbs per brewing day) of this material, leaving brewers with the problem of quick disposal. Most Microbrewers consistently brew more than two batches of beer each week. According to the Organic Farming Research Foundation, the number of organic farms has increased 20% each year since 1997. SBG could be an effective and inexpensive tool to assist new and financially stretched organic farmers suppress weeds. My proposal is to study if wet Spent Brewers Grains can be effectively used as an inexpensive mulching material. In addition to assessing weed control, effect of Spent Brewer’s Grains on quality and yield of two crops, as well as changes to pH, micro and macronutrients will also be measured. Outreach will be through local and regional Agricultural conferences, Seedsower Farm’s website, agricultural based listservs, in discussions with other farmers, and possibly publication.

    Project objectives from proposal:

    I plan to study two consecutive crops, that can be grown throughout the growing season. Shallots will be studied because they are notoriously intolerant of weeds and have little or no canopy with which to shade weed seeds, and because they are a desirable and profitable market crop. Broccoli will be studied, because of the ease of transplanting into a already mulched area and because it can be grown following onions and will complete the season for the purpose weed suppression. Broccoli is also a valuable crop for fall markets on Long Island. There would be two treatments and a control and this would be replicated four times on the same parcel, and randomly assigned. A total of four, 120 foot rows will be planted. The rows will be 42” wide with paths between each row at a 18” width. Each row will include treatment plots with SBG, Straw and a control plot with no mulch. Each treatment plot will consist of 40 feet of row space. Paths will be hoed on a regular basis to prevent weeds from creeping into the treatment beds, or if possible, mulched with cardboard to suppress weed growth.

    The first treatment would include a row using straw mulch at one inch in depth. The second treatment would use wet SBG as mulch also at a depth of one inch. Both mulches will be applied manually at the time of planting and replenished, if needed through the growing period to keep depth level consistent. The control group will have no mulch whatsoever. For purposes of statistical analysis, the plots will be assigned randomly.

    Each treatment area will be divided in half. One half (20’) will be weeded and the other half (20’) will not. The delineation of these two halves will be clearly made with 30” field flags. Weeds will be hand pulled when they have reached at least 6” in height (or 7-14 days). This will enable easier hand weeding, especially of the mulched areas where hoeing would disturb the mulch. The weeds that are pulled from the weeded half will be weighed and counted each time it is weeded (7-14 days), with care taken to remove as much soil as possible from the root system. The total weight and counts will provide quantitative measures of the weed control for the two treatment areas with mulch and will allow comparison of the effectiveness of the SBG as a weed suppressant.

    The control plots without mulch will also be split in half, delineated by field flags and weeded, weighed and counted to determine the quantity of weeds that would normally grow without a mulch barrier.

    A schematic of the above description is included as an addendum, as is the chart that will be used to record the weights and counts of weeds.

    A soil test which includes pH and macro and micronutrient analysis will be performed on the field before the growing season and again after the growing season for each of the treatment and control plots to determine if there were any changes in these measurements. An analysis of the changes, if any will be included in the final report.

    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.