News from the Compost Certification Scheme

The latest news from the compost industry


Revised tomato plant response and weeds test

Posted: 14 August, 2015. Written by Justyna

REAL CCS has published a revised version of the tomato plant response and weeds test specified in PAS 100.  The REA has carried out the revision on behalf of REAL with input from Paul Waller Consulting, the Open University and Stockbridge Technology Centre.  The latest version:

  1. incorporates many of the recommendations made as part of a WRAP supported review of the plant response test,
  2. clarifies the scope of the test and materials to use and standardises the quantities of peat and compost to use,
  3. requires that spatial and environmental variations in the controlled growth environment are checked and taken into account,
  4. provides guidance on tray layout and suitable light and temperature for germinating and growing tomato plants,
  5. specifies what must be recorded at the laboratory,
  6. gives detailed instructions for assessing, calculating and reporting the test results,
  7. includes instructions for assessing and reporting test validity, and
  8. updates a key test validity criterion, which is that plants grown in the peat control medium must achieve a mean fresh mass per plant of at least 2.0 g for each tray (an increase from 1.5 g for each tray). 

When implemented by CCS Appointed Laboratories, the revised parts of the test method should facilitate improved consistency in control plant performance. 

The field bean germination and growth test also included in the methods document remains unchanged and continues to be recommended for testing samples from all batches of compost intended for supply to the growing media sector.

The new version 3.0 of this test method is available here.