Off-seasonal soilless production of green vegetables in reused substrates in Mediterranean unheated greenhouses

Soilless cultivation is progressing slowly in low technology greenhouses (LTG) based on favorable natural conditions in Turkey similar most of the Mediterranean countries, and generally it has been applied in high technology greenhouses (HTG). Tomato and blocky type pepper are major crops for HTG which have central heating system, and vegetation period lasts nearly all over the year. On the other hand, in the LTG that covers 98% of total greenhouse area, growers prefer double season production method for fruiting vegetables in order to reduce heating costs, whereas during colder seasons the greenhouse is left empty. As a consequence, higher profitability can be achieved if the crop is produced at this off-season time. This research was conducted in PE high tunnel to determine production possibilities of some green vegetables in different substrates during off-season. The tested plants were green onion, green garlic, parsley, rocket and cress. Plants were grown in horizontal pots (75×23×16 cm) filled with three different substrates, namely perlite, clinoptilolite and coir, that were also reused after main crop production. On November 4, 2009, 30 onion shallots or 30 garlic cloves were transplanted to each pot with double line, and seeds of three leafy vegetable species (parsley, rocket, cress) were sown (in measure of 0.5 g of seeds pot-1). Plants were grown until January 5, and yield data were determined. Results showed that green vegetables can be grown in reused substrates in two months, and this method can be used for small scale farmers applying soilless cultivation in unheated greenhouses. Also, this method can be used for growing these vegetables at home gardens or balconies. © 2020 International Society for Horticultural Science. All rights reserved.