Team:Purdue/Seed sterilization



  • Sterile distilled water
  • 70% ethanol
  • 50% bleach/1 drop Tween 20: prepare 40 ml in a Falcon tube, use bleach that is less than two months old


  1. Transfer a small scoop of seed to an eppendorf tube; soak seed for 30 minutes in distelled water
  2. Spin down seed briefly in microfuge
  3. Decant water, add 500 uL 70% EtOH, vortex, spin
  4. Decant EtOH, rinse with sterile water, spin and decant
  5. Add 0.8 mL 50% bleach, vortex for 8-10 min, spin and decant
  6. Add 0.8 mL sterile water, vortex, spin, decant
  7. Repeat Step 6 six times
  8. Leave seed in 0.5 mL of 0.12% sterile agar; allow to stratify at 4 degrees for at least 2 days


  • Keep the ethanol step as brief as possible-prolonged exposure to EtOH decreases germination
  • Multiple water washes are to remove all traces of bleach which also affects germination
  • Do the procedure in a hood in the tissue culture room
  • Store washed seed for stratification in refrigerator vegetable drawer in the prep room

Courtesy of Mike Poling, Lab Technician: Horticulture & Landscape Architecture, Purdue University.