Investigating Seed Drying: the Development of Low Technology Drying Options and Methods for Measuring Seed Moisture Status
Drum dryer for small scale seed conservation projects
Seed drying is the first and most important stage in the processing of seed conservation collections. If it is very warm and humid after seed collections have been made and there will be a delay of several days or more before collections are transferred to a controlled environment, it is vital that every effort is made to dry collections during transit. For every 10% reduction in relative humidity, subsequent seed longevity approximately doubles. Impediments to effective seed drying due to characteristics of the seeds themselves or the ambient environment could result in seed death and thus a complete waste of the investment made in securing the collection.
This project looks at low technology, low cost options for drying in the field during a collecting trip and/or for drying where purpose-built facilities (i.e. ‘dry-rooms’) aren’t available. For example, the potential for cooled incubators to act as small-scale seed dryers has been quantified and this system has been adopted by MSB partners in nine different countries. At a smaller scale, we have also developed and tested a range of seed drying drums that use self-indicating silica gel as the drying agent. By November 2011, over 20 drum dryers had been supplied to MSB partners around the world.
A by-product of our studies on low-technology seed drying has been the development of the ‘mini seed bank’. Aimed mainly at Kew’s visiting public, 2,000 mini seed banks have been sold through the Kew shops and by mail-order since its launch in 2002. All of the profits from sales of the mini seed bank are channelled back into the Millennium Seed Bank Partnership.
Reliable, non-destructive and low cost options for measuring seed moisture status have also been trialled, validated and introduced to MSB partners.