Greenhouse Production Systems
Substrate Culture Systems
Floor Culture System
Floor culture systems are one of the most efficient and cost-effective methods of soilless culture, which involves replacing the soil with a media, typically sand, in the greenhouse (Figure 15.10). Floor culture systems have been successfully used for vegetable production in greenhouses and are considered a good means of providing plants with a uniform, well-drained rooting medium. The principal crops grown in sand culture systems are tomatoes and cucumbers. Sand culture systems for greenhouse crops (e.g., tomatoes or cucumbers) are typically irrigated and fertilized by drip emitters.
Advantages and Disadvantages
Floor culture systems have many advantages over other substrate systems. The fact that it is an open irrigation system, whereby the nutrient solution is not recycled, greatly reduces the likelihood of diseases such as Fusarium and Verticillium spreading in the medium. Another advantage is the excellent capillary action of sand, which results in lateral movement of nutrients so that there is an even distribution of nutrients throughout the root zone.
Bed Construction
Assuming the greenhouse has concrete footers, the soil is first removed to a depth of 12 to 16 inches (30–41cm) before lining the excavated area in the greenhouse. The footing refers to the point at which the greenhouse structure meets the soil upon which the structure rests. The floor should have a slight grade of 6 inches. (15cm) per 100 feet (30.5m) so that the area may be drained or leached when necessary.
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