Seed is sown in inert blocks made out of crushed rock. The smaller blocks for sowing the seed and the larger blocks into which they are transplanted are soaked in nutrients just before sowing in the propagating house. This house is kept at 23 degrees C for most of the three weeks it takes for the plants to be of sufficient size for ‘planting’ in the main house. Carbon dioxide enrichment is given to help the young plants to grow sturdily and have sufficient carbohydrates for photosynthesis in the dark period of the winter and extra light is also given, for sixteen hours a day, to help growth. We sow during the first week of December so that the plants are ready for planting before Christmas.