Dry climate conditions, crop rotation and a short growing period make the summer cultivation in greenhouses to a problem in Germany. Further prices for tomatoes and cucumbers are low at this time. Vegetable growers are increasingly opting to crop rotations, using ornamental pot plants. Further greenhouse area for transplant production are insufficient in production around the year. Often soil culture isn't possible because the soil is covered with sheets of plastic or concrete. On the other hand, soilless culture equipment is too expensive for a short growing period. Due to the high heating costs in Germany the vegetable production season extend from March to October. Experiments with melons (Cucumis melo var. cantalupensis), aubergine (Solanum melongena), runner beans (Phaseolus vulgaris var, vulgaris) and lambs lettuce (Valerianella locusta) as alternative Vegetable crops for summer and winter were carried out with a hydroponic-system called Plant Plane Hydroponic (PPH), which permits crop rotation of plants that require different plant spacing. The growing period for the vegetable crops was between 12 and 20 weeks. The total yield was 7.3 - 7.8, 5 - 6, 2 - 4 and 1.2 kg/m(2) for melon, aubergine, beans and lambs lettuce, respectively. The high N-level of lambs lettuce was below the critical level of 3500 ppm during the winter. Product quality and economic efficiency of growing alternative crops are discussed.
