NL2027825B1 - Cultivation floor system and method - Google Patents

Abstract

The invention relates to a cultivation floor system with a floor on which plant containers are placed. The cultivation floor system comprises a watertight basin and a water-permeable 5 structure in the basin. The water-permeable structure is covered by a permeable top fabric which forms the floor onto which the plant containers are placed. The structure has one or more layers of granular material, such as for example of volcanic rock, e.g. lava granules. Preferably, as is also the case in known systems, the top fabric is a woven top fabric having small pores between the yarns of the top fabric. A perforated film is placed between the 10 permeable top fabric on the one hand and the permeable structure on the other hand. The perforated film is made of impermeable film material which is provided with distributed perforations in such a manner that the film reduces the free evaporation surface for water from the permeable structure.

Description

P34758NLO0/SBI Title: CULTIVATION FLOOR SYSTEM AND METHOD The invention relates to a cultivation floor system with a floor on which plant containers are placed. The cultivation floor system comprises a watertight basin and a water-permeable structure in the basin. The water-permeable structure is covered by a permeable top fabric which forms the floor onto which the plant containers are placed. The structure has one or more layers of granular material, such as for example of volcanic rock, e.g. lava granules. Preferably, as is also the case in known systems, the top fabric is a woven top fabric having small pores between the yarns of the top fabric. A perforated film is placed between the permeable top fabric on the one hand and the permeable structure on the other hand. The perforated film is made of impermeable film material which is provided with distributed perforations in such a manner that the film reduces the free evaporation surface for water from the permeable structure.

The system furthermore comprises an ebb/flood watering installation which is configured to supply water so that water is available for the plants in the plant containers and comprises one or more irrigation lines on the bottom of the basin covered by the water-permeable structure, which irrigation lines have openings along their length, the installation being configured for water to flow from the one or more irrigation lines to flood the basin to a level above the permeable top fabric and to relief water from the basin. A cultivation floor system according to the preamble is known from EP 2955996. In practice, undesirable effects occasionally may occur during use of such cultivation floor systems.

One problem is that plant roots may grow more than desired when the plant containers are placed on the cultivation floor. This results in plant roots protruding below from the plant containers. This has a number of adverse effects. For example, the plant containers look less appealing and the plant containers are less stable on the floor due to the protruding roots.

The invention is aimed at providing an improved cultivation floor system and cultivation floor thereof, by means of which the above mentioned problem can be alleviated. The invention provides a cultivation floor system according to the preamble of claim 1, which is characterized in that the cultivation floor system further comprises a gas supply and distribution system, for example for supply of air and/or CO:, wherein the gas supply and

2.

distribution system comprises a network of gas supply lines distinct from the irrigation lines and configured for distributing a gas across the floor, which network is provided in the basin lower than the perforated film, preferably embedded in the water-permeable structure or on the bottom of the basin, and wherein the gas supply and distribution system further comprises a gas supplying installation for supplying gas to the network so that, in use, the gas flows from the network through the perforations of the perforated film and reaches the plant containers placed on the floor.

The network is provided below the perforated film, e.g. at least 5 centimeters below the film, generally between the bottom of the basin and the perforated film. For example, the network is provided embedded in the water-permeable structure in the basin, for example, in a granular layer of the water-permeable structure or on the bottom of the basin.

The invention is based on the insight that plant roots grow when they are in contact with water. Due to the growing conditions provided for the plant, e.g. in a greenhouse, the plant roots need little water to start growing. A second insight is that the plant roots remain moist even when the water has flowed out of the basin. This causes the plant roots to grow even after watering the plants resulting in the protruding plant roots.

The gas supply and distribution system, for example, allows the roots of the plants to be dried after the water has flowed out of the basin by distributing the gas across the floor and allowing it to flow to the plant containers placed on the floor. By placing the network below the perforated film the gas is distributed homogeneously over the surface of the floor. This allows the roots of plants in plant containers placed on the floor to be dried homogeneously providing a homogenous effect over the extent of the floor, which enhances uniformity and quality of the plants that are cultivated.

Furthermore, by distributing the gas through the floor structure, the roots of the plants in the containers are more effectively reached. By controlling the moist levels of the roots by virtue of operation of the watering system in combination with the gas supply and distribution system the growth of the roots may be controlled. Thus, in practice, after cultivation the plants may have strong roots which do not or not unduly protrude from the plant containers.

Another advantage of the invention is that by supplying a gas, such as air, by the gas supply and distribution system to the cultivation floor growth of the plants may be controlled, e.g. improved. The growth may be controlled by controlling the temperature of the gas, the composition of the gas and/or the humidity of the gas.

-3- A further advantage of the invention is that by supplying a gas, such as air, by the gas supplying and distribution system parts of the cultivation floor system, such as e.g. the permeable top cloth, may be dried by the gas. This allows for further control of conditions of the cultivation floor system. The invention is advantageously placed in a greenhouse. The gas supply and distribution system may be used to supply a gas, for example air, e.g.

conditioned air, O2 and/or CO, to the floor in order to provide a better climate for the plants to grow in. The gas may further be a gas composition designed to stimulate the growth of the plants contained in the plant containers or which activates flower induction of the plants in the plant containers. The gas may be supplied at a rate of 2-10 m? per hour, e.g. 5 m? per hour.

For example, in operation, the gas supply and distribution system may supply air, e.g. low humidity air, in order to dry the floor surface and remove residual water that could trigger undue growth of the roots of the plants.

For example, in operation, the gas supply and distribution system may supply CO: or a mixture of air and CO; in order to enhance growth of the plants.

The gas supply and distribution system may be used to supply conditioned air to influence temperature and/or humidity of the zone where the plants are growing. For example, cooled air is supplied in order to cool the zone, e.g. in a greenhouse where the air above the zone has a higher temperature, e.g. in summer Thus the system allows for a more versatile control of the conditions wherein plants in plant containers are grown.

In an embodiment perforations are provided in the permeable top fabric, e.g. which are located on top of perforations in the perforated film, such that the perforations in the permeable top fabric and the perforations in the perforated film form gas channels which allow gas to effectively flow therethrough.

In an embodiment, the network is provided at least 5 cm below the top fabric. This allows the gas to flow optimally from the network through the perforations of the perforated film to plant

-4- containers placed on the floor. If the network is provided too close to the top fabric the gas may not be equally distributed over the surface of the floor.

In an embodiment, the distributed perforations of the perforated film have an average opening of between 0.75 mm? and 108 mm?, wherein the perforations form, preferably, at most 10% of the surface area of the perforated film. The top fabric prevents water, which may remain behind in the water-permeable structure, after the water is let out of the basin, from evaporating, which may lead to the growth of algae in the cultivation floor system. It is found in experiments that distributed perforations with an average opening according to this embodiment allow for a good water supply to the plants while also preventing water from evaporating from the water-permeable structure.

In an embodiment, the network for distributing gas is embedded in one of the one or more layers of the water-permeable structure. For example, the network is embedded in a granular layer of the water-permeable structure. The granular layer provides for enhanced distribution of the gas. In another embodiment, {part of) the network for distributing gas is embedded in the bottom of the basin. This may reduce the overall height of the cultivation floor.

In an embodiment, the network for distributing gas is kept at an overpressure by the gas. This allows for a uniform distribution of gas to be supplied to the gas containers.

In an embodiment, the irrigation lines are placed parallel in the basin, for example in a longitudinal direction of the longitudinal basin, e.g. the basin extending between parallel rows of roof-supporting columns of a greenhouse.

Preferably the irrigation lines are distributed evenly in the basin. This allows the water to rise and fall evenly through the entire basin. It further allows the water to enter and leave the basin efficiently and swiftly.

In an embodiment, the network comprises one or more perforated gas distribution lines each having along the length thereof perforations for emitting the gas, e.g. with an inlet connected to a main gas pipe and with a closed end. For example, multiple perforated gas distribution lines extend parallel to one another from a common main gas pipe, e.g. perpendicular to the main gas pipe.

In an embodiment, the watering installation comprises multiple parallel irrigation lines and the one or more main gas pipes extend parallel to the irrigation lines, e.g. each main gas pipe

-5. centred between a pair of adjacent irrigation lines. Perforated gas distribution lines branch off from each main gas pipe, e.g. in opposite directions, e.g. perpendicular to the main gas pipe. In an embodiment, the network comprises a main gas pipe, e.g. which extends parallel to the irrigation lines, e.g. centred between a pair of irrigation lines, and perforated gas distribution lines branch off from the main gas pipe in opposite directions, e.g. perpendicular to the main gas pipe. In other embodiments it is possible that the main gas pipe is not parallel to the irrigation line and/or that the perforated gas distribution lines are not perpendicular to the main gas pipe and/or the irrigation lines.

In an embodiment, the network comprises a main gas pipe, e.g. which extends parallel to the irrigation lines, e.g. centred between a pair of irrigation lines. The perforated gas distribution lines branch off from the main gas pipe in opposite directions, e.g. perpendicular to the main gas pipe, each perforated gas distribution line having a blind end and a length of between 3 and 5 meters. For example, the system is installed in a greenhouse having parallel rows of roof-support columns spaced 8 meters from one another. In an embodiment, the network for distributing gas comprises perforated gas distribution lines having along the length thereof perforations for emitting the gas, e.g. with an inlet connected to a main gas pipe and with a closed end, wherein multiple perforated gas distribution lines extend, e.g. parallel to one another from a common main gas pipe, e.g. perpendicular to the main gas pipe, and wherein a flow rate adjusting device is present at the inlet of each perforated gas distribution line. For example, the device allows for setting the flow rate upon installation of the floor system.

The perforated gas distribution lines can be embodied as perforated pipes and/or hoses. An effect of arranging the perforated gas distribution lines at an angle, e.g. perpendicular, to the irrigation lines is that the perforated lines do not interfere unduly with the flow of water in the permeable structure. For example, when arranged on the bottom, this orientation prevents formation of puddles in the basin which may negatively influence the performance of the cultivation floor system. The perforated pipes and/or hoses may have, in practical embodiments, a diameter between 15-35 mm, for example between 20-30 mm, for example 25mm.

-6- For example, the perforated pipes and/or hoses are evenly distributed in the cultivation floor, e.g. they are provided parallel to each other at intervals of 0.5 — 1.5 meter, e.g. of 1 meter. The perforations in the pipes and/or hoses may be provided at intervals between 60 - 200 cm, for example at 80 cm. The perforations in the gas distribution network may have a diameter between 0,5 - 5mm, for example between 2 - 4mm.

In an example, the irrigation lines are provided parallel in the longitudinal direction of the basin. A main gas pipe which is part of the network for distributing gas is provided in the longitudinal direction below the perforated film, e.g. between the perforated film and the bottom of the basin, e.g. embedded in the granular material filled in the basin. In this embodiment, the perforated pipes and/or hoses are connected to the main gas pipe which supplies the gas to the perforated pipes and/or hoses.

For example, the cultivation floor system may be provided in a greenhouse with a width of 8 meter between rows of roof-supporting columns. Herein, the gas supplying line may be provided in a longitudinal direction in the middle of the width of the section of the greenhouse such that the perforated pipes and/or hoses extend about 4 meters in either direction of the gas supplying line. An effect of having relatively short individual perforated hoses and/or pipes is that a more or less equal amount of gas may flow through each perforation of the perforated pipes and/or hoses.

In an embodiment, the gas supply lines of the gas supply and distribution system are provided inside the irrigation lines of the watering installation. For example, the irrigation lines in this embodiment may be placed parallel in the basin and the gas supply lines may be provided inside the irrigation lines. This allows for easier installation of the system. It may also allow for a more compact gas supply network and irrigation system in the basin.

In an embodiment, the network is supported at a distance above the bottom of the basin by spacers, and then embedded in granular material. This allows water to flow underneath the network into and out of the basin. The spacers may be concrete or plastic spacers. In embodiments the spacers are separate spacers that are placed on the bottom of the basin.

In an embodiment, the gas supplying installation comprises a blower to supply air to the network.

-7- In an embodiment, the gas supply and distribution system is adapted to heat or cool the gas before distributing the gas over the surface of the floor. By bringing the gas to a desired temperature before distributing the gas over the surface of the floor, the growth conditions of the plants in the plant containers may be better controlled, e.g. by better controlling the climate wherein the plants grow. This allows for more versatile and efficient growing of the plants. In embodiments, the network for distributing gas may be split in separate networks for distributing gas, for example which are provided in different parts of the cultivation floor system, such that one part of the surface of the cultivation floor is supplied with warmer gas and another part of the surface of the floor is supplied with cooler gas. This allows to create ideal conditions for different plant varieties.

The invention is also related to a method wherein use is made of a cultivation floor system according to the invention.

In embodiments, the gas supply and distribution system is operated to reduce or avoid growth of roots out of the container, e.g. by effecting or enhancing a drying out of the floor.

In embodiments, the cultivation floor system may be used to vary the period and/or interval of supplying gas to the cultivation floor, e.g. based on the amount of water supplied to the cultivation floor. It may be advantageous to supply gas to the cultivation floor, and the plant containers placed thereon, following watering the plants, e.g. to dry the roots of the plants.

In embodiments, the cultivation floor system may be used to supply additional CO: to the plants contained in the plant containers to improve growth conditions for the plants. In embodiments the cultivation floor system may be used to supply O: to the plants contained in the plant containers. In embodiments the cultivation floor system may be used to supply air to the plants contained in the plant containers. In embodiments the humidity level of the gas may be controlled.

In embodiments, gas is supplied to the cultivation floor on regular intervals, e.g. gas is supplied for 1 hour with 1 hour intervals, e.g. gas is supplied to the cultivation floor for a period of more than 24 hours without interruption. The amount of gas provided, frequency of supplying gas, and composition of gas provided may depend on the plant variety and plant size to be grown on the cultivation floor.

-8- The invention is further related to a method for installing a cultivation floor system comprising a cultivation floor configured for placing plant containers thereon, which method comprises: - providing a watertight basin having a bottom and a perimeter with a top edge; - placing one or more irrigation lines in the basin, which irrigation lines have a multitude of openings along their length for passage of water through said openings, - connecting a water supply and discharge system including a water pump to the one or more irrigation lines; - installing a gas supply and distribution system comprising a network for distributing gas which is installed in the basin; -filling into the basin one or more layers of loose granular material, e.g. lava granules; - compacting the one or more layers of loose granular material so as to provide permeable granular material structure in the basin, wherein the one or more irrigation lines and the network for distributing gas are covered by the granular material structure, - providing a substantially horizontal top surface of the compacted permeable granular material at a level at or, preferably, below the top edge of the perimeter of the watertight basin, - covering the top surface of the compacted permeable granular material by a water- permeable fabric, e.g. a (woven) fabric or a mat, wherein the water supply and discharge system is configured to cause a supply of water via the one or more irrigation lines so that the water-permeable granular material structure in the basin is flooded with water and the water level is above the water-permeable fabric, which water level is maintained for a flood period so that water is absorbable by the plants in the plant containers, and wherein the water supply and discharge system is configured to cause a discharge of water via the one or more irrigation lines so that the water-permeable granular material structure in the basin is relieved from the water after the flood period and wherein the gas supply and distribution system is configured to cause a supply of gas via the network through the perforations of the perforated film to reach plant containers placed on the floor.

A second aspect of the invention relates to a cultivation floor system with a cultivation floor on which plant containers are placeable or placed, comprising: - a watertight basin comprising a bottom and a perimeter; - a water-permeable structure comprising at least a layer of a granular material, e.g. lava granules, filled in the basin; - a permeable top fabric which covers the water-permeable structure and which forms a top side of the floor on which plant containers are placeable,

-9-

- optionally, a perforated film placed under the permeable top fabric, which perforated film is made of impermeable film material which is provided with distributed perforations, which film reduces the free evaporation surface for water from the water- permeable structure,

- a watering installation which is configured to supply water so that water is available for the plants in the plant containers, optionally an ebb/flood watering installation which comprises one or more irrigation lines,

characterized in that the cultivation floor system further comprises a gas supply and distribution system, for example for supply of air and/or CO, wherein the gas supply and distribution system comprises a network of gas supply lines distinct from the irrigation lines and configured for distributing a gas across the floor, which network is provided in the basin lower than the top fabric, preferably embedded in the water-permeable structure or on the bottom of the basin, and wherein the gas supply and distribution system further comprises a gas supplying installation for supplying gas to the network so that, in use, the gas flows from the network and reaches the plant containers placed on the floor.

The floor system according to the second aspect of the invention may have one or more of the features described herein in relation to the system of claim 1 and embodiments thereof.

The invention also relates to a greenhouse provided with a cultivation floor system according to the invention and/or wherein use is made of a method according to the invention.

The various aspects of the invention will be explained below with reference to the drawing, in which: - Fig. 1 diagrammatically shows a cultivation floor system to illustrate the invention; and - Fig. 2 shows a cross section of a part of the figure 1. Figure 1 diagrammatically shows a cultivation floor system 1 on which plant containers are placed comprising a watertight basin 4. The basin 4 has a bottom profile 12 which is produced in a bed, for example in a bed of sand.

Several U-shaped channels 14 are provided in the bottom profile 12 and extend substantially parallel to each other.

Although two channels 14 are shown in Figure 1, the bottom profile 12 may comprise significantly more channels 14. On either side of each channel 14, the bottom profile 12 comprises a bottom surface 16 which runs off towards said channel 14. After the bottom profile 12 has been formed, the bed of the bottom profile 12 may be covered with a watertight membrane 12a.

-10 - An irrigation line 7 is provided in each channel 14. The irrigation lines 7 preferably have a closed and smooth, non-corrugated peripheral wall. The irrigation lines 7 are, for example, formed by plastic pipes with smooth walls, such as PVC pipes. The outer diameter of the irrigation lines 7 may correspond to the curvature of the bottom of the U-shaped channels 14, in other words the channels 14 are produced with a cross section which corresponds to the cross section of at least the bottom portion of the irrigation line 7 to be accommodated therein.

When installing the irrigation lines 7, each irrigation line 7 may already have been provided with several lateral outflow openings 8, which are a distance apart in the longitudinal direction of this irrigation line 7, for example equidistant from each other. Instead, it is also possible for one or more irrigation lines 7 to be configured such that they are initially closed, that is to say have a closed pipe wall, in which case the outflow openings 8 are made after these irrigation lines 7 have been accommodated in the channels 14 and preferably in the exposed top portion of these irrigation lines 7.

The outflow openings 8 can be made in the irrigation lines 7 in different ways. The outflow openings 8 are, for example, made using a tool which is provided with a base comprising guide means, for example wheels, which are configured to engage with an irrigation line 7.

The tool can be placed on an irrigation line 7 and moved along the irrigation line 7. Ata location where an outflow opening 8 is desired, the tool may perform an operation on the irrigation line 7 to form the outflow opening 8, for example by drilling, milling, sawing, burning, cutting, or punching.

The irrigation lines 7 are part of the watering installation which, in this embodiment, further comprises a valve assembly 21. The irrigation lines 7 are connected to the valve assembly 21 via a supply/discharge line 20. The valve assembly 21 is furthermore connected to a water storage 11 and a water pump 10.

A water-permeable structure 5 is arranged in the basin 4. The water-permeable structure 5 preferably comprises one or more layers of granular material, but may also (or in combination with the latter) comprise one or more water-permeable mats.

In this case, the irrigation lines 7 are covered by the water-permeable structure 5.

-11 - The water-permeable structure 5 furthermore comprises a permeable and horizontal top layer which forms a cultivation floor 2. The top layer comprises a top fabric 17, such as a woven top fabric, in which pores are present between the yarns of the fabric.

The top fabric 17 is permeable, having a relatively high porosity and small pores. Preferably, the top fabric is woven, for example from suitable synthetic yarn, and the pores between the yarns of the top fabric 17 are relatively small. The top fabric is preferably UV-resistant and also wear-resistant, for example suitable to be driven over by lightweight vehicles.

The top fabric 17 in figure 2 is situated directly on top of a perforated film 40 containing perforations 41, so that the perforated film is present between the permeable top fabric 17 on the one hand and the water-retaining layer 5 on the other hand, which perforated film is made of impermeable film material which has been provided with distributed perforations in such a manner that the film reduces the free evaporation surface of water from the water-retaining layer 5 preferably by at least 50%, more preferably by at least 90%.

Preferably, the cultivation floor 2 is sufficiently stable to drive across it with a vehicle. Plant containers 6 containing plants to be grown or the like are placed on the cultivation floor

2. The plant containers 8 are, for example, partly open on the underside and/or are configured to be completely or partly water-permeable.

The water storage 11, the water pump 10, the valve assembly 21, the supply/discharge line 9 and the irrigation lines 7 together form the watering installation, e.g. an ebb/flood watering installation which is configured to alternately cause a supply of water to the cultivation floor 2 and a discharge of water from the cultivation floor 2, preferably with a highest water level above the top fabric.

The cultivation floor system 1 further comprises a gas supply and distribution system 18, 19 comprising a gas supplying installation 18 and a network.

In this embodiment, the network comprises a main gas pipe 23 and multiple perforated distribution lines, e.g. pipes and/or hoses 19, branching from the common main gas pipe 23.

Each line 19 has along the length thereof perforations for emitting the gas, e.g. with an inlet connected to a main gas pipe and with a closed end.

-12- In an embodiment, a flow rate adjusting device is present at the inlet of each perforated gas distribution line 19 In this embodiment, the gas supplying installation 18 is connected to the main gas pipe 23 which is embedded in the basin 4 between two channels 14. The main gas pipe 23 is connected to the perforated pipes and/or hoses 19 which are provided perpendicularly to the irrigation lines 7.

In operation, gas flows from the gas supplying installation 18 through the main gas pipe 23 towards the perforated pipes and/or hoses 19. The gas then flows out of the perforated pipes and/or hoses into the water-permeable structure 5 and then through the perforations in the film 40 and through the fabric. The gas rises uniformly towards the cultivation floor 2 and to the plant containers 6.

In embodiments, the gas supplying installation 18 is configured to heat and/or cool the gas before supplying it to the network for gas distribution. This, possibly in combination with a variable frequency and/o flow rate of gas flow, allows for controlling a climate around the plant containers 6.

With the cultivation floor system 1 a uniform irrigation and a uniform supply of gas to the plant containers 6 is achieved.

Figure 2 diagrammatically shows a cross section, not to scale, of the structure of a cultivation floor system 1.

Figure 2 shows a cross section showing a perforated pipe 19 supported by spacers 22 such that the perforated pipe 19 is supported away from the bottom of the basin 4. This allows water to flow below the perforated pipe 19 and avoids formation of puddles. In other embodiments the perforated pipe 19 is placed on the bottom of the basin 4.

The perforated pipe 19 is connected to the main gas pipe 23, which in this embodiment is not embedded in the water-permeable layer 5.

As an optional feature, a permeable mat 45 is situated underneath the perforated film 40, directly on top of the granular material 5 that has been filled in the basin.

-13- The mat 45, preferably, forms a stabilizing mat on top of the granular layer 5. For example, the mat 45 is a three-dimensional open structured geomat, e.g. produced from thermally bonded extruded polymer, e.g. polypropylene, monofilaments.

In an embodiment, the mat 45 is a capillary mat 45 which has a capillary action in the horizontal direction and in the vertical direction, for example a non-woven mat of fibrous elements, for example a compacted non-woven mat. As a result thereof, transportation of moisture underneath the film is also possible in a horizontal direction, for example from plant to plant. Alternatively, but less advantageously, the mat 45 is situated between the top fabric 17 and the perforated film 40. The film 40 is closed as such, and therefore does not allow water or water vapour to pass, except at the location of the perforations 41 in the film 40. In this way, the film 40 forms an, albeit imperfect, barrier to water, as it were, which, due to the (usually heated) climate in the greenhouse (or optionally due to heating in the cultivation floor itself) will want to evaporate from the layer 5 and rise up through the permeable structure and the permeable top fabric. The film 40 significantly reduces the free evaporation surface, as it were. As a result thereof, water which has remained behind in the water-permeable structure 5 can evaporate much less readily. Furthermore, this vapour only rises up in the film 40 at the location of the perforations 41, as a result of which it is readily possible for the top fabric 17 to dry out in the regions between these perforations. The size of the perforations 41 is preferably chosen to be such that the perforations do not impede a possible through-flow of water in an ebb/flood watering installation. For example, perforations 41 with diameters of between 1 mm and 12 mm or perforations with corresponding dimensions in terms of surface area are provided if a non-round shape is chosen.

-14 - For example, the distance between adjacent perforations 41 in the film 40 or between groups of smaller perforations is at least 10 mm, as a result of which dry zones can readily occur in the top fabric 17.

In a practical embodiment, a perforated film 40 is provided which is made of impermeable film material, e.g. of plastic film, which is provided with distributed perforations 41 having an average opening of between 0.75 mm? and 108 mm?, wherein the perforations preferably form at most 10% of the surface area, if desired at most 5% of the surface area.

In an advantageous embodiment, the perforated film 40 is a single-layer plastic film. The invention is not limited to the cultivation floor system described in Figures 1 and 2. The person skilled in the art can make various modifications which fall within the scope of the invention.

Claims (15)

-15- CONCLUSIONS Cultivation floor system (1) with a cultivation floor (2) on which plant holders (6) can be placed, comprising: — a watertight basin (4) with a bottom (16) and a perimeter; — a water-permeable structure (5) with at least one layer of granular material, for example lava granulate, arranged in the basin (4); — a permeable topsheet (17) covering the water-permeable structure (5) and forming a top of the floor (2) on which plant holders (6) can be placed, — a perforated film (40) placed under the permeable topsheet (17) which perforated film (40) is made of a non-permeable film material provided with distributed perforations (41), the film reducing the free evaporation surface for water of the water-permeable structure (5), — an ebb-tide watering installation which configured to provide water such that water is available to the plants in the plant containers (6) and comprising one or more irrigation conduits (7) at the bottom of the basin (4) covered by the water-permeable structure, the irrigation conduits (7) include openings (8) along its length, the installation being arranged so that water flows from the one or more irrigation pipes (7) to irrigate the basin to a level above the the permeable top cloth (17) and for draining water from the basin, characterized in that the cultivation floor system (1) further comprises a gas supply and distribution system (18, 19, 23), for example for supplying air and/or CO :, wherein the gas supply and distribution system (18, 19, 23) comprises a network of gas supply lines which are different from the irrigation lines and are arranged to distribute a gas over the floor (2), the network (19, 23) provided in the basin below the perforated film (40), preferably embedded in the water-permeable structure or on the bottom of the basin, and wherein the gas supply and distribution system further comprises a gas supply installation (18) for supplying a gas to the network (19, 23) so that, in use, the gas of the network (19, 23) flows through the perforations (41) of the perforated film (40) and the plant containers (6) placed on the floor (2) have been reached. Cultivation floor system according to claim 1, wherein the network (19, 23) for distributing gas is arranged at least 5 cm below the top cloth (17). -16 - Cultivation floor system according to claims 1 or 2, wherein the network (19, 23) for gas distribution is embedded in the water-permeable structure, for instance in the layer of granular material. Cultivation floor system according to one or more of claims 1 - 3, wherein the gas distribution network (19, 23) comprises one or more perforated gas distribution pipes which have perforations along the length thereof for expelling the gas, for example with a entrance connected to a main gas pipe and having a closed end, for example a plurality of perforated gas distribution pipes extending parallel to each other from a common main gas pipe, for example perpendicular to the main gas pipe. Cultivation floor system according to one or more of claims 1 - 4, wherein the watering installation comprises several parallel irrigation pipes (7), and wherein one or more main gas pipes (23) extend parallel to the irrigation pipes (7), for example wherein each main gas pipe is centered between a pair of adjacent irrigation lines, and wherein perforated gas distribution lines branch from each main gas pipe, e.g. in opposite directions, e.g. perpendicular to the main gas pipe. Cultivation floor system according to one or more of claims 1 - 5, wherein the network comprises a main gas pipe (23), for example which extends parallel to the irrigation pipes, for example centered between a pair of irrigation pipes, and wherein perforated gas distribution pipes branch from the main gas pipe into opposite directions, for example perpendicular to the main gas pipe. Cultivation floor system according to one or more of claims 1-6, wherein the network comprises a main gas pipe (23), for instance which extends parallel to the irrigation pipes, for instance centered between a pair of irrigation pipes, the main gas pipe having a length of at least 25 meters, and wherein perforated gas distribution pipes branch from the main gas pipe in opposite directions, for example perpendicular to the main gas pipe, each perforated gas distribution pipe having a closed end and a length between 3 and 5 meters. Cultivation floor system according to one or more of claims 1 - 7, wherein the gas distribution network (19, 23) comprises perforated gas distribution pipes which have perforations along a length thereof for expelling the gas, for example with an entrance connected to a main gas pipe and having a closed end, wherein a plurality of perforated gas distribution pipes extend, for example parallel to each other, from -17 - a split main pipe, e.g. perpendicular to the main gas pipe, and wherein a flow rate adjusting device is provided at the entrance of each perforated gas distribution duct. Cultivation floor system according to one or more of the preceding claims, wherein the network (19, 23) is supported at a distance from the bottom (16) of the basin (4) by spacers (22) placed on the bottom (16) of the basin (4) are arranged, for example for filling the basin with the granular material. Cultivation floor system according to one or more of the preceding claims, wherein the gas supply and distribution system (18, 19, 23) is adapted to heat and/or cool the gas for distributing the gas, for instance air, via the network over the surface of the floor (2). A method for growing plants in plant containers, preferably in a greenhouse, wherein use is made of a cultivation floor system (1) according to one or more of the preceding claims 1-10. A method of growing plants according to claim 11, wherein the gas supply and distribution system (18, 19, 23) is arranged to heat and/or cool the gas for distributing the gas over the floor (2) and wherein the method comprises heating and/or cooling the gas before distributing the gas through the network. A method according to claim 11 or 12, wherein the gas supply and distribution system (18, 19, 23) is operated to reduce or prevent the growth of roots from the container, for example by influencing or improving a drying of the floor . 14. Method for installing a cultivation floor system (1) comprising a cultivation floor (2) adapted for placing plant holders (6) thereon, which method comprises: - providing a watertight basin (4) with a bottom and a perimeter with a top edge; - placing one or more irrigation pipes (7) on the bottom of the basin (4), the irrigation pipes (7) each having a plurality of openings (8) along its length for the passage of water through said openings (8), - connecting a watering installation, for example a water supply and drainage installation with a water pump (10), to the one or more irrigation pipes (7); -18 - — installing a gas supply and distribution system (18, 19, 23) comprising a gas distribution network (19, 23) installed in the basin {4); — filling the basin with one or more layers of loose granular material, for example lava granulate; - compacting the one or more layers of loose granular material to obtain a permeable granular material structure (5) in the basin (4), wherein the one or more irrigation pipes and the gas distribution network are covered by the granular material structure, - providing a substantially horizontal top surface of the compacted permeable granular material at a level of or, preferably, below the top edge of the perimeter of the watertight basin, - covering the top surface of the compacted permeable granular material by a water permeable cloth (17), for example a (woven) cloth or a mat, wherein the water supply and drainage system is arranged to supply water via the one or more irrigation pipes (7) so that the water-permeable granular material structure (5} in the basin (4 ) is irrigated with water and the water level is above the water permeable cloth (17), maintaining the water level during a floodp period such that the water is absorbable by the plants in the plant containers, and wherein the water supply and drainage system is arranged to cause a drainage of water through the one or more irrigation pipes (7) so that the water-permeable granular material structure (5) in the basin is stripped of the water after the flood period, and wherein the gas supply and distribution system (18, 19, 23} is arranged to cause a supply of gas through the network and through the perforations {41} of the perforated film (40) so as to to reach the plant holders (8) placed on the floor (2). 15. Greenhouse provided with a cultivation floor system (1) according to one or more of claims 1-10 and/or wherein use is made of a method according to one or more of claims 11-13.