Retting and Turning
Retting is the process of beginning to separate the bast fibres from the hurds or other plant tissues. It is done in the field, taking advantage of the natural elements of dew, rain and sun, or under controlled conditions using water, enzymes or chemicals. The method chosen depends on the end use to which the fibre will be put. Suitable industrial processes for water and chemical retting have not been developed.
Successful field retting requires a delicate balance of nightly dews and good daytime drying conditions. The southern Ontario climate may dictate that field retting be done no earlier than the end of July in order to assure adequate dew conditions. Planting date and selection of variety are factors in predicting a suitable harvest date.
The length of the retting process is critical for optimum fibre yield and quality. It normally takes 21-28 days to complete, but dry August weather with low dew conditions may necessitate longer retting periods. Occasionally, the process may take as little as 14 days.
The windrows are turned vigorously once or twice with a tedder or rake to facilitate even retting of the windrow and to knock the leaves off the stems. It is important that the retting process be complete before baling, so that the fibres reach the desired colour, and do not rot or discolour in storage. In wet conditions, a third turning may be necessary.