System and method for growing a plant in an at least partly conditioned environment

Abstract

A system for growing a plant (1) in an at least partly conditioned environment includes a cultivation base (11) for receiving a culture substrate (3) with a root system (4) of the plant therein. Root temperature control elements (12) are provided which are able and adapted to impose a predetermined root temperature on the root system, and lighting elements (20,21,22) which are able and adapted to expose leaves of the plant to actinic artificial light. Leaf heating elements are also provided, which are able and adapted to impose on the leaf of the plant a leaf temperature varying from an ambient temperature. In a method for growing the plant a carbon dioxide assimilation management of a leaf system of the plant is thus influenced, and a supply of actinic light, the root temperature and the carbon dioxide assimilation management are adapted to each other.

Claims

1. A method for producing and harvesting a crop in a daylight-free environment comprising: growing the crop in a culture substrate in a multi-layer daylight-free cultivation system having a number of cultivation shelves above one another, controlling, in each of said cultivation shelves, a photosynthesis of the crop by controlling a light spectrum supplied to the crop from light emitting diodes, controlling, in each of said cultivation shelves, a root temperature of a root system of the crop at a desired value, controlling, in each of said cultivation shelves, carbon dioxide assimilation of a leaf system of the crop by controlling a leaf temperature difference of the leaves compared to ambient temperature wherein, in each of said cultivation shelves, the control of photosynthesis by controlling the light spectrum, the control of the root temperature, and the control of the carbon dioxide assimilation by controlling a leaf temperature difference of the leaves compared to ambient temperature are adapted: to one another, forcing the crop into an intended carbon dioxide assimilation, and controlling an evaporation of said crop via the leaf by regulating a correct amount of energy on the leaf.

2. The method as claimed in claim 1, wherein the supply of light, the root temperature, and the leaf temperature are adapted to each other depending on the crop.

3. The method as claimed in claim 2, wherein the artificial light spectrum, the leaf temperature of the leaf, and the root temperature are controlled individually of each other but in mutual relation, depending on the crop.

4. The method as claimed in claim 3, wherein a control is provided between a leaf heating means (30) and a root temperature control means (12) which imposes a mutual dependence on the leaf temperature and the root temperature.

5. The method as claimed in claim 1, wherein the leaf temperature of the leaf of the crop is controlled by a leaf heating means (30) that comprise at least one heat source that irradiates the leaf with infrared radiation.

6. The method as claimed in claim 1, wherein the root temperature is controlled by a root temperature control means (12) that comprise a closed conduit system for receiving therein during operation a liquid flow with a controlled temperature, and wherein the conduit system is allowed to enter into heat-exchanging contact with said culture substrate.

7. The method as claimed in claim 1, wherein the leaf temperature is caused to follow a change in root temperature in a directly proportional manner.

Description

BRIEF DESCRIPTION OF THE DRAWING FIGURES

(1) The invention will now be further elucidated on the basis of an exemplary embodiment and an accompanying drawing. In the drawing:

(2) FIG. 1 shows a cross-sectional partial view of a device in an exemplary embodiment of a system according to the invention.

(3) The FIGURE is otherwise purely schematic and not drawn to scale. Some dimensions in particular may be exaggerated to greater or lesser extent for the sake of clarity. Corresponding parts are designated as far as possible in the FIGURE with the same reference numeral.

DETAILED DESCRIPTION OF THE INVENTION

(4) The system shown in FIG. 1 makes use of a multi-layer cultivation of plant 1 so as to enable the best possible use of an available surface area. The plant is accommodated here in culture trays 2 with a suitable culture substrate 3 therein, such as earth, glass wool, rockwool or simply water, for the purpose of receiving a root system 4 of the plant therein. Culture trays 2 are placed one above the other on beams 11 of a frame 10 constructed almost entirely from stainless steel. Any desired number of such carriages 10 can thus be combined to form a complete cultivation system in a conditioned environment, wherein the plant is brought to full development in fully controlled manner. Irrigation and fertilizing provisions (not further shown) are arranged at or in carriages 10 in order to provide the plant with sufficient water and the necessary nutrients.

(5) Beams 11 of the carriages each comprise a closed conduit system 12 of a hose or tube which meanders at a regular pitch. In this respect a system of successive hollow fins can optionally also be applied as conduit system. This conduit system 12, through which a heat-carrying medium such as water of a controlled temperature can be guided in order to control a temperature of the root system, forms part of root temperature control means. The heated medium relinquishes heat during operation to for instance the beams, which in turn conduct the heat via the culture trays to the culture substrate with the root system of the plant therein. Conversely, heat can also be extracted from the root bed by means of a cooled heat-carrying medium. The root system is thus kept more or less precisely at a desired root temperature during operation according to the method described here. In order to give this heat transport a more specific control, and thereby a more efficient heat-exchanging capacity, the beams take a multi-layer form with an insulating base 13 of foamed plastic such as polyurethane foam or polystyrene foam, with a reflective top layer 14, for instance a reflective metal coating or an additional intermediate layer provided with such a coating, followed by conduit system 12 and thereon a metal plate 15, for instance of stainless steel, having good thermal conductivity.

(6) Each layer of cultivation system 10 is provided with an artificial light source 20 in the form of a light fitting having therein groups 21 of light-emitting diodes (LEDs), in addition to possible other light sources 22 such as ultraviolet or infrared radiators. The LED diodes in the first groups emit light at least mainly in the visible part of the spectrum, in particular red, yellow, green or blue light, while the second groups 22 add invisible components such as infrared light and near-ultraviolet light thereto. Light fittings 20 are provided with a control (not further shown) with which the different groups and the elements within the groups can be controlled selectively and individually in order during operation to then adapt a specific spectral composition of the emitted light to the requirements and type of the plant 1 being cultivated. Because the beams are optically separated from each other to a significant extent, a different spectrum can if desired thus be supplied per beam in order to thus cultivate different plants in combination with each other and provide each with an optimal spectrum. The system is highly suitable here for application in a low-daylight or even daylight-free environment, such as for instance in an underground situation.

(7) Further provided in the cultivation system are leaf heating means 30 in the form of infrared radiators which are disposed in layers on either side on the shelves of the carriages. The infrared radiators emit direct heat radiation in the direction of the leaf of the plant and thus, if desired, increase a leaf temperature of the leaf relative to the ambient temperature. The carbon dioxide assimilation management of the leaf can thus be controlled to a significant degree and particularly be adapted to the root pressure of the sap flow in the plant which is produced by root system 4. This because heating of the leaf results in a widening of the stomata in the leaf, whereby they will be better able to relieve surplus root pressure by allowing water to evaporate, while a sufficient carbon dioxide assimilation required for the photosynthesis, which is in turn activated and controlled using the lighting means, nevertheless continues via these same stomata. If on the other hand cuttings of the plant are taken, the leaf system is however not heated, or at least heated less, at an increased root simulation so as to thus limit evaporation and ensure an excess of moisture on the cutting surface. All in all, the main growth factors, i.e. the photosynthesis, the root pressure and the carbon dioxide assimilation, can thus be regulated individually in the system according to the invention, and these factors are precisely adapted in mutual relation at each stage of growth and for each plant in order to enhance optimum growth and mode of growth.

(8) Although the invention has been further elucidated above on the basis of only a single exemplary embodiment, it will be apparent that the invention is by no means limited thereto. On the contrary, many other variations and embodiments are possible without requiring a skilled person to depart from the scope of the invention in a manner which is less obvious. The root temperature control means can thus also comprise a conduit system directly in the culture substrate which is in more or less direct heat-exchanging contact with the root system. In the case of cultivation on water or a watery substrate, such as glass wool or rockwool, the root temperature can also be controlled by a controlled control of the temperature of the water supplied thereto.

(9) Use is made in the example of artificial light by means of light-emitting diodes (LEDs), although within the scope of the invention conventional incandescent growing lamps are also suitable instead, and the invention can also be applied in full or partial daylight.

(10) Use is made in the given example of multi-layer cultivation on mobile carriages, although cultivation in a single layer and/or cultivation in a fixed arrangement can also be envisaged within the scope of the invention.

(11) Within the scope of the invention the carbon dioxide assimilation and moisture evaporation via the leaf system can be controlled and adapted to particularly the root pressure. Instead of by means of direct infrared lamps, this can also be achieved by means of spiral filaments, heat panels or the like disposed close to the leaf system. If desired, the leaf heating means, such as the infrared radiators in the example, can further be integrated in the same fitting as the artificial lighting means, for instance for the purpose of saving space and/or ease of installation.

(12) What is really important in the invention is that the growth development of the plant is determined by the weakest link in a chain of the most important growth factors, i.e. photosynthesis, root pressure and carbon dioxide assimilation, and that all these factors are controlled in mutual relation according to the invention and, if desired, are artificially modified in order to realize an optimal chain.