Overwinter transplant production for extended season organic cropping (OF 0144)

Summary

The objectives of this project (Defra project OF0144), lead by EFRC, were to:
• identify acceptable organic fungicide products to control mildew in transplant production
• produce integrated organic transplant production systems for brassica, allium and lettuce over the autumn and winter period by identifying optimum cell/block sizes in relation to nutrient requirements and sources, growing media formulation, and supplementary feeding and watering
• evaluate developed transplant production protocols during the winter period
• undertake technology transfer and dissemination of the results
Results:
Protocols were tested for a range of crop species and varieties, growing media, cell size and feeding regimes over the three seasons under experimental and commercial conditions. It is possible to produce transplants of a suitable quality over the winter period although propagation time is generally longer than at more favourable times of year.
With respect to identifying acceptable fungicide products
• a range of fungicidal products was identified including L-Carvone, Mycosin, fennel and clove oils that showed potential in controlling mildew on a range of crop species. However the work also raised the question of the suitability of the use of such materials in organic systems which has not been resolved.
• work on spectral filters found no benefits to their use in transplant production
• cell size has minimal effect on disease spread
As far as integrated organic transplant production systems are concerned:
• production time was longer overwinter than in spring
• lettuce was relatively easy to produce in a range of media and block sizes with no supplementary feed being necessary
• similarly cabbage was relatively easy to produce although feeding was required
• cauliflower was produced using smaller cell size and full nutrient compost