S06 - Session P2 - A new way of growing leeks: open air hydroponics proves to be economically feasible

Authors: Tomas Van de Sande *, Tim De Cuypere

In Europe, Flanders is market leader in the export of leek (Allium porrum L.) for the fresh market. The soil-bound cultivation of leek however faces a growing number of adversities. Legal constraints on fertilizer use become increasingly strict and make it difficult to grow high-quality leek required by the fresh market. Due to climate change the need for irrigation and availability of water becomes an issue. The availability and effectiveness of plant production products decreases while markets are increasingly demanding lower pesticide residues. Moreover, the availability of suitable cropland for farmers is low in Flanders. Closer spacing distances and faster growth in open air hydroponics (Deep float technique, DFT) cause a substantial yield increase. Net yields of 320 tons/ha*year are possible. This means one hectare of soilless grown leek can replace up to 8 hectares of conventional leek. The cost of plant protection can decrease drastically, leek is clean when harvested and automatization of the harvesting process is possible. In this context, growing leeks hydroponically becomes interesting. This requires a newly developed growing system and automatization of planting and harvesting. High investment costs are now the main obstacle for growers to switch to hydroponic leek growing. Seven years of experiments at the inagro campus, combined with detailed information on investment costs and production process allows calculation of the feasibility of leek grown hydroponically. A robot is currently being developed and is integrated in a harvesting unit that allows separate caption of clean by-products (leaves, roots). Results of the first tests show - even after storage - no damage to the leeks. A test pilot for growing leek hydroponically has recently been installed at the inagro campus. When scaled up and combined with the mechanical harvesting unit, the investment costs of this pilot can be written in a reasonable time period.