Protocol developed by participants of the NE-1013 snap bean project.  For further information, contact:


Kent Burkey, Ph.D.

USDA-ARS Plant Science Research Unit

NC State University

3127 Ligon Street

Raleigh, NC   27607



The following protocol is based on a small plot approach so that multiple plantings are possible without requiring significant land area.


Soil preparation:

  • Use a rototiller or other available equipment to prepare a seed bed free of weeds and debris.
  • Slow-release fertilizer will be applied after emergence as a side dress to discourage weed growth between rows.


Plot design:

  • Each plot will be a single 3-meter (~10-ft) row.
  • Row spacing of approximately 1-meter (flexible to accommodate equipment and availability of plot land).
  • Two adjacent rows will form an experimental block containing the two snap bean lines.
  • Each planting date will consist of 4 experimental blocks (8 rows).
  • Randomly assign bean lines (e.g. S156 and R331) to the rows within each 2-row block.
  • Distinctive border plants (e.g. yellow wax beans) are an option to separate sequential plots.


Planting and plant density:

  • Manually prepare furrows approximately 2 cm deep.
  • Inoculate seeds with commercial preparation of Rhizobium (e.g. Lipha Tech Company, 3101 W. Cluster Ave., Milwaukee, WI 53209, 1-800-558-1003; inoculum “D” for common bean). [Natural Rhizobium populations are often not very effective, and it is unclear how effective commercial preparations will be under our fertilization regime, but for consistency each location should inoculate.]
  • Hand-plant 60 inoculated seeds in each 3-meter plot. Space as 30 sets of 2 seeds approximately 10 cm (~4 inches) apart.
  • Water the seed bed immediately after planting to enhance uniform germination, but do not water again until after emergence.
  • After emergence, thin to 24 plants per 3-meter plot…12 in each 1.5-meter subplot (see “Harvests”).



  • Beginning 1 week after emergence, provide water equivalent to 1 inch of rain per week by either natural rain events or application using available equipment. Drip irrigation would be ideal; Raleigh is very happy with a landscaping irrigation product called Netafim Techline. Based on a row width of 1 meter, 6.7 gallons of water per linear meter of row (or 20 gallons per 3 m row) is a volume equivalent to 1 inch of rain over the 1 m2 area but applied as a strip within each row. This is a contrived system, but we need a standard approach. In addition, regions with high temperatures and low humidity may have extremely high evapotranspiration rates that require more water than other regions, so customized watering regimes will need to be developed for individual locations.
  • Incorporate a single application of slow release fertilizer as a side dress at thinning (Scott’s Osmocote Plus, NPK 15-9-12 with micronutrients, 3-4 month release period). 30 g/plant x 24 plants = 720 g distributed evenly along each row and incorporated by hoeing as part of the process of ridging up soil around the plants.
  • Remove weeds manually as required; rototiller between rows, hand weeding within rows.
  • Pest and pathogen problems will be unique to each location and should be treated (and carefully documented) using recommended chemicals/practices for the region. If root rot is a problem, some form of soil sterilization made be required depending on severity of the problem and other circumstances.


Harvests: Randomly assign 1.5-meter subplots for mid-season and final harvests within each 3-meter plot

  • Mid-season: Multiple harvests of “marketable” pods from 10 of 12 plants in the mid season subplot (exclude plant #1 and #12 that are considered border plants). Use visual estimate of pod maturity to determine harvest date. Decided to use multiple fresh pod harvests instead of a single “biomass” harvest in case pods develop at different rates even though flowering will begin at the same time in S156 and R331.


  • Final: When >75% of pods are brown, harvest 10 of 12 plants in the final harvest subplot (exclude plant #1 and #12 that are considered border plants) for determination of final pod number per plant. Dry pods to constant weight to determine pod yield, total seed number and seed weight per plant, and average weight per seed.