SOWING SCHEDULES FOR PROCESSING TOMATOES

The aim of this three year field trial from 1991 to 1993 was to obtain the longest possible processing-tomato harvest period for the Guadiana Valley (western Spain). Cultivars H-324-1 and UC-82-B were sown at nine fifteen-day intervals each year from the middle of February to the middle of June were harvested over an 85-day period from July 20 to October 13. All seeds sown at the first three intervals were immediately covered by transparent polyethylene mulching. The next three intervals used two groups of seeds, one group was mulched and the other was not. Seeds sown at the last three intervals were not mulched. Seeds sown after the beginning of June produced too few ripe fruits. Mulched sowing at the earlier intervals, up to the beginning of April, shortened times to harvest, but had no effect on crops sown later. Crops sown between the middle of February and beginning of April gave satisfactory yields, but these varied each year, mainly because the weather each year during the corresponding sowing-to-harvest periods was different. Fruit yields of crops sown after the beginning of May tended to decrease. Yields of tomato juice from the fruits was independent of sowing date, but the soluble solids (°Brix) of fruits of the later sowings tended to decrease. Sowings after middle of May should be made with early varieties because the later ones do not ripen sufficiently.