AU2009200747A1

AU2009200747A1 - Hydroponic green feed production

Info

Publication number: AU2009200747A1
Application number: AU2009200747A
Authority: AU
Inventors: Peter Samuel Doyle
Original assignee: GREENE GRASS Pty Ltd
Current assignee: GREENE GRASS Pty Ltd
Priority date: 2002-11-04
Filing date: 2009-02-25
Publication date: 2009-03-19
Also published as: AU2002952537A0; AU2003259629A1; AU2003259629B2

Description

Australian Patents Act 1990 Regulation 3.2A ORIGINAL COMPLETE SPECIFICATION STANDARD PATENT Invention Title HYDROPONIC GREEN FEED PRODUCTION" The following statement is a full description of this invention, including the best method of performing it known to us: Q:\OPER\RSH\Jan 09 June 09\30723156-DIV.5.doc PXOPERU4XC\2&j93U723156 .di,.do.23102l09 -1- Hydroponic Green Feed Production.

The present invention relates to a seedling production facility including an apparatus for producing seedlings. More particularly, but not exclusively, the invention relates to the production of fodder comprising of seedlings.

By the term seedlings as used herein there is meant seedlings or sprouts of seeds or grains (hereinafter referred to as "seeds") including but not limited to wheatgrass, alfalfa, clover, broccoli, radish, onion, lucerne, mong beans, snow peas, and sprouts and so-called micro- 0 greens. Micro-greens are seedlings such as for example, but again not limited thereto, herbs, lettuce, spinach, basil, rocket, broccoli, radish, beetroot, silver-beet and tatsoi that may be grown to a height of for example, substantially 36 to 50mm. The top 25mm, for example, may then be cut off and used in salads and the like.

Changing environmental, social and economic conditions are forcing farmers to look for alternative livestock feeding means to replace and supplement traditional forms. As such, the practice of hydroponically producing fodder for example, for livestock feed from seeds such as barley, oats, wheat, triticale and rye on an industrial scale is becoming increasingly common. Using hydroponic techniques, seeds may be germinated into sprouts that are grown to form a thick fodder with interwoven roots that is high in both nutrients and enzymes.

Hydroponic techniques allow the fast production of fodder with a cycle typically ranging from 8 to 15 days under a variety of controlled conditions in enclosed greenhouses, often in P:OPERWMXC\2X9~3O723156 -didoc-23A)2/2IXJ9 -2locations where harsh environmental conditions are prohibitive to plant growth. These low cycle times ease the problems of large quantity and long term feed storage that confront many livestock farmers, particularly over winter, and the substantive nutrient loss associated therewith. The controlled environment allows growers to monitor fodder nutrient and bacteria content. Further, as only a relatively small area is required to implement a hydroponic fodder production cell, such an operation is both labour and cost effective.

Previously proposed hydroponic fodder growing systems involve seeds that have been saturated in a water-based solution being placed in a series of substantially rectangular trays.

O The seeds initially, and later the fodder mass, are then fed by a water-based nutrient solution from overhead sprays periodically, typically for a duration in the order of 2 to 3 minutes every 4 hours. The solution feeds the seed or fodder mass, filtering through the mass under the force of gravity to the tray below where it is caught and nutrient is recycled for use elsewhere, but not recirculated back into the nutrient tank. No medium is used for growing 5 the fodder.

Generally, the closed environment in which the fodder is grown is permanently artificially lit by fluorescent lighting or other means and maintained at a relatively constant temperature of around 22 degrees Celsius. The trays in which the fodder grows can also be heated from below. The period of time over which the fodder propagates will vary between systems and is dependent on numerous factors including the type of seed and nutrient solution used, and environmental conditions. As mentioned above, typically this period is upwards of 8 days in any case. At the end of this time the fodder and inter-woven rootlet mat, often having a P.:OPERWXC,2I(IXI)j72316 di dOC.23I)2flM9 weight at least five times that of the initial seed mass, is lifted off the tray as a single sward of S fodder that can be easily transported and fed to livestock. Typically livestock will eat both the rootlet mat base and grassy portions of the fodder.

The nutrient solution used in previously proposed hydroponic fodder growing systems has typically been delivered to the seeds by overhead spraying units. The regular use of these overhead nutrient sprays substantially increases the humidity in the greenhouse environments normally employed however. Excessive humidity gives rise to damping-off at the base of the fodder and various other plant diseases, and the propagation of mould, spores and powdery 0 mildew, all of which may result in significant economic loss to the grower through lost feed production.

In accordance with one aspect of the present invention, there is provided a seedling production facility comprising: an enclosure and within the enclosure, a seedling production apparatus comprising: at least one channel open at is upper side to receive a seed mass, said channel having a base; an inlet supply for irrigating the channel with a nutrient solution; an outlet downstream of the inlet supply means for draining the channel; and means for controlling the temperature and humidity within the enclosure between predetermined values to prevent rotting of the seed mass.

P.%OPER\MXC%2OYU0723 156. ,do23M2I09 -4- Preferably, the inlet supply is arranged to distribute nutrient solution directly into the base of the channel. The inlet supply may distribute the nutrient solution across the width of the channel. The inlet supply may be arranged above the base of the channel such that the inlet supply is above a seed mass received in the channel in use. The inlet supply may be arranged to distribute the nutrient solution as a film flowing along the base of the channel.

Preferably, the outlet is closable to flood the channel and openable to subsequently drain the nutrient solution from the channel.

0 Preferably, the temperature and humidity within the enclosure is controlled by an airconditioning system. Preferably, the air-conditioning system is a reverse cycle airconditioner.

Preferably, the ambient temperature within the enclosure is controlled within the range of substantially 20 to 22 degrees Celsius.

Preferably, the relative humidity within the enclosure is below 80%. The relative humidity within the enclosure may be substantially Preferably, the enclosure is thermally insulated. The enclosure may have restricted natural light access to prevent excessive internal heating of the enclosure.

P:OPER\MXCQ')9130723 156 didoc.-23f)2f(M) Preferably, the channel is inclined in the longitudinal direction of the channel to promote the flow of the nutrient film solution from the inlet supply to the outlet. The channel may have a gradient of substantially 1:30 in the longitudinal direction of the channel from the inlet supply to the outlet.

Preferably, the depth of the channel is sufficient to receive a seed mass at least substantially deep and no more than substantially Preferably, the apparatus seedling production facility further comprises a capillary medium 0 arranged on the base of the channel and configured to support the seed mass.

Preferably, the inlet supply is provided at one end of the channel, a further inlet supply is provided at the other end of the channel, the outlet is provided in a part of the channel intermediate the inlet supply and the further inlet supply, and the channel is inclined downwardly from each of its ends towards the outlet.

Preferably, the inlet supply is arranged to continuously irrigate the seed mass with the nutrient solution to provide a continuous flow along the base of the channel. Alternatively, the inlet supply may be arranged to periodically irrigate the seed mass with the nutrient solution. The flow of the solution may be controlled by a dosing unit.

P:OPER\MXCU21)9 0723156 divdx-23/2AIM -6- Preferred embodiments of the present invention will now be described, by way of example only, with reference to the accompanying drawings, in which: Figure 1 is a cross-section view of a channel used in the production of fodder in accordance with one embodiment of the invention; Figure 2 is a plan view of the inlet end of the channel of Figure 1; Figure 3 is a plan view of the outlet end of the channel of Figure 1; 0 Figure 4 is a perspective view of the rootlet mat base and sprouts of grown fodder in a channel according to an embodiment of the present invention; Figure 5 is a perspective view of adjacent channels, one having the seed mass distributed within the channel and one having grown fodder according to an embodiment of the present invention; Figure 6 is a schematic plan view of one possible arrangement of multiple channels to form a fodder production facility according to an embodiment of the present invention; Figure 7A and 7B are schematic side and end views respectively of one section of the channels of Figure 6; and P :\OPER\MXCI2I1X)93723156 -di doc-23A)2/21I69 -7- Figure 8 is cross-section view of one possible enclosure for housing the fodder production facility shown schematically in Figure 6.

In Figure 1, a cross-section view of a hydroponic production channel or tray 10 for producing green feed/seedlings, for example in the form of fodder 12 (best seen in Figures 4 and is shown. The channel 10 comprises a base 14, and sidewalls 16, 18. Preferably the base 14 is in transverse cross-section shaped so that a central part of the base indicated by arrow 20 is lower than lateral outer parts. This lowered central part 20 of the base 14 may have a depth 0 of approximately 1.5 to 2mm for example, as is evident in Figure 1, and may have the form of a slight concave portion or smaller channel running along centreline 50 of the base 14 in the longitudinal direction. In one practical form, for example only, the base 14 is approximately 225 mm wide with this dimension indicated by the reference numeral 24, while the sidewalls 16,18 are approximately both 68mm high with these dimensions respectively indicated by the reference numeral 26, 28, although it is to be understood that other channel 10 dimensions are possible within the scope of the invention.

With reference to Figures 2 and 3 which show the inlet 30 and outlet ends 32 of the channel respectively, the hydroponic channel 10 has a nutrient solution supply inlet 34 connected to a nutrient tank 36 via a nutrient solution supply pipe 38 for supplying a water-based nutrient solution at the inlet end 30, and a nutrient solution drainage outlet 40 for draining the nutrient solution from the channel 10 at the outlet end 32 of the channel 10 back to the nutrient tank 36 via a drainage return pipe 41. The channel 10 is inclined in the longitudinal P OPERMXCU I)723156 di doe-23A)2'21)9 -8direction with respect to the horizontal to give the channel 10 a gradient of approximately 1:30 from the supply inlet end 30 of channel 10 to the drainage outlet end 32. This promotes the gradual flow of a nutrient film of solution along the channel 10 during the supply of the nutrient solution. This lowered central part 20 deters the nutrient film from travelling along one side of the channel 10 by promoting the film to the centre of the channel 10. While the tilting of the channel 10 from one end to the other as described may be sufficient for channel lengths up to approximately 6m for example, for longer channel 10 lengths it may be preferable to divide the channel 10 to provide a supply inlet 34 at each end 30, 32 and to tilt the channel 10 downwardly from each end towards a drainage outlet 40 situated intermediate 0 the ends 30, 32.

The supply inlet 34 preferably feeds the nutrient solution onto the base of the channel.

Advantageously, the supply inlet 34 distributes the nutrient solution across the width of the channel 10. A simple form of supply inlet 34 for this purpose may comprise of a t-piece 42 connected to the inlet supply pipe 38, with the solution being delivered from the opposite ends of the transverse limb 48 of the t-piece 42 at opposite sides of the centre line 50 of the channel For growing fodder for example, germinable seed such as barley or other suitable germinal seed may be pre-soaked in mains tap or bore water (pH 5.5 to 6.5) for approximately 4 hours.

The pre-soaked seed may then be placed in the channel 10 by hand. The seed is spread evenly over the length of the channel to the maximum depth consistent with ensuring that the entire depth of the seed mass 22 is exposed to contact with the nutrient solution by capillary P %OPERWXCU(n9*1UO72i 15 -disdm13/O I2N) -9action. With the channel 10 having a base 14 approximately 225mm wide this requires approximately kg, in the case of barley seed 22 for example, of seed 22 per metre of the channel 10 length. This will vary with both the channel 10 size and the size and type of seed 22 used. To aid in distributing the seed 22 evenly, a flat piece of wood (not shown) may be dragged across the top surface of the seed mass 22. In Figure 5, a mass of seeds 22 that has been evenly distributed in a channel 10 is shown.

Substantially employing the Nutrient Film Technique (NFT), which has previously been proposed for hydroponic cultivation of small plants, nutrient solution is periodically fed using 0 a supply pump 54 shown in Figure 6 from the nutrient tank 36 into the channel 10 through the inlet supply pipe 38 to the supply inlet 34 to irrigate along the base of the channel 10, for example for 3 to 5 minutes every 4 to 6 hours. For a channel 10 approximately 225mm in width as described, the flow rate may be approximately 0.5 litres per minute for example.

The nutrient solution flows in the form of a film along the base 14 of the inclined channel and the base of the seed mass 22 under the force of gravity. Capillary action within the seed mass 22 draws the nutrient solution up from the base 14 of the channel 10 to seeds 22 in the upper portion of the seed mass 22 to facilitate the germination of substantially all of the seeds 22 and eventual growth of the sprouts 56. The nutrient film is dispersed evenly amongst the seed mass 22 on both sides of the channel 10 by capillary action throughout the seed mass 22.

It will be appreciated that the above durations and intervals, together with the rate at which the nutrient is fed into the channel 10, have been provided for example only. For example, the nutrient solution may be continually fed into the channel 10 at a substantially slower feed P: OPER\MXC20')31)723156 div doc-23/2/21WXY) rate to provide a continuous slow flow along the base of the channel 10. The nutrient solution in a further alternative form, may be pulse fed into the channel 10, whereby the feeding of the nutrient solution occurs for 15 minutes for example, with the flow rate of the nutrient solution being adjusted accordingly, before pausing for 30 minutes and then 5 cyclically repeating. In a still further alternative, the nutrient solution may be fed into the channel 10 at predetermined times of the day, for example for a duration of 3 to 5 minutes at 8am, 12pm, 4pm and 8pm.

Excess nutrient solution not absorbed by the seed mass 22 over the length of the channel 10 is 0 returned to the nutrient tank 16 via the drainage outlet 40 and drainage return pipe 41. The recirculating of the nutrient solution results in reduced running costs as substantially only the nutrient solution consumed by the seed mass 22 needs to be replaced. It also minimises environmental damage from release of the nutrient solution to the external environment.

The use of NFT to nourish the seed mass 22 largely governs the depth to which the seed 22 is placed in the channel 10. It has been found that, depending on seed 22 type and size, when this seed mass 22 has a depth of less than approximately 5mm, in the case of barley seeds for example, the seed 22 is likely to be washed along the channel 10 with the flow of the nutrient solution. However, when the depth of the seed mass 22 exceeds approximately 10mm it has been found that the seeds in the upper part of the mass 22 may not be exposed to sufficient nutrient solution by capillary flow, whereby seeds 22 may not germinate and may rot thereby suppressing fodder 12 growth.

P OPER\MXC\2I1XJ9~30I)7231 6 didoc-233l)2J2(n)9 -11- The NFT phase is conducted for approximately eight days, although it will be appreciated that this time will be subject to considerable variation, particularly when growing microgreens for example. Over this duration the fodder 12, having a rootlet mat base 60 and sprouts 56, grows from the seed mass 22 to a height of approximately 250mm. Each kilogram of barley seed for example, has been found to produce approximately 8kg of fodder 12. As can be seen in Figure 4, the swards of fodder 12 can be easily removed by hand from the channel 10 at the conclusion of the process.

Only the NFT is employed to irrigate the seed mass 22 and growing seedlings 60. In 0 particular, no overhead irrigation sprays, which potentially may give rise to the humidity problems associated with previously proposed systems, are exploited in the production of the seedlings The nutrient solution used is preferably specifically formulated for this purpose. In one preferred form it comprises two separate mixes, "part A" comprising calcium nitrate, and "part B" comprising potassium nitrate, potassium phosphate, magnesium sulphate, iron chelates, manganese sulphate, boric acid, copper sulphate, zinc sulphate, ammonia molybdenum. Both of these mixes are prepared and held in separate part A 64 and part B mixing tanks 66. These mixing tanks 64, 66 are connected separately to the nutrient tank 36 that receives equal proportions of the two parts from the mixing tanks 64, 66 as governed by a dosing unit (not shown), when required.

P OPER\WXCOI19I13U723156 -di ,dom23A2A1X)9 12- The nutrient level, alkalinity and temperature of the nutrient solution in the nutrient tank 36 are all closely monitored.

The nutrient level of the solution has been found to be related to the Electrical Conductivity (EC) of the solution, which is monitored automatically with an EC measuring device (not shown) sampling from the nutrient tank 36. A nutrient content that falls within the corresponding EC range of approximately 0.8 to 1.8 milliSiemens per centimetre has been found to be optimal for hydroponic green feed production. Too little nutrient content in the solution inhibits the growth of the fodder 12 whilst on the other hand, nutrient levels that are 0 too high give rise to soluble salt damage. The EC level, and therefor the nutrient content, of the solution in the nutrient tank 36 is maintained within this optimal range by the dosing unit that pumps small equal amounts from each of the mixing tanks 64, 66 to the nutrient tank 36 when the nutrient content of the solution drops.

The pH of the nutrient solution in the nutrient tank 36 is monitored automatically with a pHmeasuring device and adjusted by a dosing unit (neither of which are shown). Fodder 12, wheatgrass, sprouts and micro-greens for example can typically survive when being fed with a nutrient solution having a pH substantially in the range of 5.0 to 7.0. If the pH of the nutrient solution falls below 5.0 then it can potentially burn the propagating roots of the rootlet mat base 60, while if the pH level rises above 7.0, the nutrients may precipitate out of the nutrient solution. The pH of the nutrient solution is preferably maintained at around 6.3.

p ,OPE R A1X0lrJ\'7231 6~ div d-2/I)02J21)) -13- The temperature of the nutrient solution is preferably kept below 30 degree Celsius, and more S preferably 22 degrees Celsius. If the temperature rises above 30 degrees the nutrients start to precipitate out of the solution. A temperature control unit (not shown) will automatically stop the dosing of nutrient to the nutrient tank 36 if the temperature rises above this level.

When the nutrient solution cools sufficiently, the nutrients will re-enter the solution, and the dosing process will be recommenced. A cooling tower (not shown) can be installed to help alleviate this problem. Further, this problem may also be addressed somewhat by locating the nutrient tank 36 below ground to substantially maintain the nutrient solution in the nutrient tank 36 at a constant temperature. The temperature of the nutrient solution should also be 0 kept above 14 degrees Celsius as at this temperature the fodder 12 growing time can extend out to 12 days or more. More preferably, the temperature of the nutrient solution is kept above 16 degrees Celsius.

The ambient temperature of the environment in which the fodder 12 is grown is preferably maintained between 20 to 22 degrees Celsius.

Previously proposed hydroponic growing systems are typically located in greenhouse type buildings often comprising a substantially transparent roof and walls that may be in the form of glass or polymer sheets for example. These greenhouses, while allowing in a plentiful supply of natural light, generally have very poor thermal insulation properties. As such, the temperature in these buildings is subject to considerable variation as a result of conduction heating due to the significant levels of uncontrolled radiant heat resulting in the above mentioned problem of the precipitation of the nutrients from the nutrient solution.

P\OPER\WXCN'M91307231 -56. dx-23Al)V2[X)9 -14- When growing fodder 12 according to an embodiment of the present invention, it has been found that while only limited light, natural or otherwise, is required, controlling the ambient temperature of the growing environment in the above mentioned range of 20 to 22 degrees Celsius is most desirable for the effective growing of the fodder 12. Accordingly, it is preferable that the fodder 12 is grown in a temperature controlled and stable environment.

Figure 8 for example, shows a cross section of one suitable enclosure 68 for housing a fodder 12 production system according to an embodiment of the present invention. The thermally 0 insulated enclosure 68 allows only restricted natural light access to prevent excessive internal heating, and is typically erected on a concrete slab 70. The lower portions 72, 74 of the walls 76, 78, to a height of approximately of 2.5m for example, and the roof 80, are constructed from zinc aluminium sheeting. The upper portions 82, 84 of the walls 76, 78 are constructed from substantially transparent polycarbonate sheeting, thereby providing limited natural light access for both individuals to work in and the photosynthesis process. The upper portions 82, 84 of the walls 76, 78 are approximately 0.5m for example, such that the walls 76, 78 of the enclosure 68 are approximately 3.0m for example. The inside of the lower portions 72, 74 of the walls and the roof 80 are heavily insulated with for example, air-cellular, thermo reflective construction insulation sold under the trade mark AIR-CELL, while the polycarbonate upper portions of the walls are preferably double glazed. This insulation and double glazing limits the amount of radiant heat that is conducted through the walls 76, 78 and roof 80 of the enclosure 68, largely in contrast to the heat conduction properties of typical greenhouses. This allows the temperature within the enclosure 68 to be more readily P: OPERMXC NIA).II723 15 6 dv dc-23I)22) maintained at a relatively cool, in comparison to many greenhouses, substantially average and constant temperature of approximately 21 degrees Celsius.

The relative humidity in the enclosure 68 should be maintained at between 40 to 80%. A relative humidity higher than 80% will give rise to the humidity problems of previously S proposed fodder production systems, while a humidity lower than 40% will dry out and stilt the growth of the seed mass 22. Preferably the relative humidity is maintained at approximately 0 A reverse cycle air-conditioner 86 is used to monitor and maintain the ambient temperature and relative humidity at the desired levels.

While an embodiment of a single channel 10 version green feed process and corresponding apparatus have been described previously herein it will be understood that the invention can be readily applied to multiple rows and layers of channels 10, that may be interconnected, to implement a practical green feed production facility. One example production facility having a multiple row and layer arrangement of channels 10 is shown for example, in plan view in Figure 6. The channels 10 are arranged in multiple layers, in this instance 7 layers, as shown schematically in the side and end views of Figures 7A and 7B respectively. Common supply inlets 34 and drainage outlets 40 that are in communication with the nutrient tank 36 by inlet supply 38 and outlet return pipes 41 can be shared between adjacent channels 10. The multiple channel 10 arrangement shown in Figures 6, 7A and 7B, when used in the P.IOPERMXC\2J 3I723I136 di,doc-23A)2J2) I9 -16production of fodder 12 from barley seed for example, has been found to produce approximately 900kg of fodder 12 per day.

Preferably, the channels 10 are cleaned after every 'harvest', part A B mixing tanks 64, 66 are washed out every 3 months to remove any clay deposits and the floor is kept clean from dirt and seedling pieces. This is to prevent disease, insects, and parasites from being brought into the growing area from outside and to provide an optimum growing environment. The channel 10 may be manufactured from PVC for example, to facilitate this cleaning. An ozone generating unit (not shown) is used in the nutrient tank 36 to kill pathogens and 0 pythium, and oxygenates the nutrient solution in the nutrient tank 36. A water conditioner (not shown), such as for example those sold under the trade mark CALCLEAR, is used to prevent calcium build up inside the pipes 38, 41) leading to and from the nutrient tank 36, as well as improving the uptake of calcium in the fodder 12.

As an alternative, it is contemplated that the nutrient solution could be delivered into the channel containing the seed mass and/or the growing seedlings using a flood and drain technique. The nutrient solution is pumped from the nutrient tank by a pump to substantially immerse the seed mass and/or growing seedlings in nutrient solution. An overflow standpipe that may drain back to the nutrient tank having an opening above the seed mass prevents the channel from overflowing.

After the pump has substantially flooded the channel with nutrient solution, the pump is deactivated, and the nutrient solution is allowed to drain through the seed mass.

P: OPERMXCUIMJX3)1723156 div do -23A)2/2I 9 -17- S With this alternative it is important that the channel has a sufficient slope to ensure that the nutrient solution is able to drain along the base of the channel back to an outlet. Without sufficient slope of the channel to provide for this drainage flow, excess residual quantities of the nutrient solution may be held within the seed mass. This may lead to the seed mass rotting and going rancid, possibly resulting in fungal growth and suppression of shoot development. This can lead to the rotting seed mass fermenting and substantially increasing in temperature, leading to many of the problems of previously proposed hydroponic systems.

0 In one form, the inlet from the pump can be at a lower drainage point of the channel and the nutrient solution can thereby drain back to the pump and nutrient tank (or direct to the nutrient tank) for subsequent use.

In a further alternative, the nutrient solution may be delivered by either intermittently or continuously dripping or running from one or more feeding taps at one or both of the ends of the channel, or even from a series of feeding taps leading out from a nutrient solution supply pipe running along the length of, and above, the channel. The taps feed the nutrient solution into the channel from above the seed mass into the channel. As with the alternative previously discussed, the nutrient solution drains through the seed mass and flows along the base of the channel to an outlet, with the channel being inclined at a sufficient slope to ensure the flow to the outlet is sufficient to ensure that excess residual quantities if nutrient solution are not held within the seed mass leading to the seed mass rotting and going rancid, possibly resulting in fungal growth and suppression of shoot development as discussed above.

P:.OPERWMXC\20\3072315f6 dvdO-23A2/22I I19 -18- Although described above by way of example only with reference to the use of germinable barley seed 22 to produce the fodder 12, it will be readily understood that the invention is equally applicable to, but not limited thereto, a range of other germinable seeds including those as hereinbefore mentioned such as rye, oats, wheat, alfalfa, clover, broccoli, radish, onion, lucerne, mong beans and snow peas, and sprouts and micro-greens generally.

When growing micro greens for example, a capillary medium (not shown) in the form of a mat for example, may be used. The mat can be pre-soaked before being placed into the 0 channel. A mass of preferably pre-soaked seeds may then be evenly distributed across the mat in the channel, and the NFT again employed to irrigate the channel with a flow of nutrient film along the base of the channel.

The seeds used when growing micro greens are typically significantly smaller than those used when growing fodder for livestock consumption for example, and the seed mass distributed across the mat generally has a considerably lesser depth. The capillary mat prevents these smaller seeds from being washed along the length of the channel with the flow of nutrient film by allowing the roots of the germinated seeds to inter-weave into the mat. When the micro-green seedlings have grown to a height of approximately 50mm for example, the seedlings may be removed from the channel by removing the mat and the seedlings interwoven by their roots therein from the channel. The top 25mm of the micro-green seedlings for example, may then be cut off for use.

P:OPERMXC(Ixj9\30723 I56 di, doc-21A)/21K)9 -19- The mat and roots of the seedlings can be suitably disposed of. The mat may be constructed from any suitable material, such as for example hessian, or rice paper. Preferably, the capillary medium or mat is biodegradable. In one preferred embodiment, the used mat may be later used as livestock feed, the livestock consuming both the mat and the base of the seedlings that is inter-woven therewith.

The method and apparatus according to embodiments of the present invention have been described above by way of example only and modifications and variations may be made without departing from the spirit and scope of the invention described.

0 Throughout the specification, unless the context requires otherwise, the word "comprise", and variations such as "comprises" or "comprising", will be understood to imply the inclusion of a stated step or integer or group of steps or integers but not the exclusion of any other step or integer or group of steps or integers.

The reference to any prior art in this specification is not, and should not be taken as, an acknowledgement or any form of suggestion that that prior art forms part of the common general knowledge in Australia.

Claims

1. A seedling production facility comprising: an enclosure and within the enclosure, a seedling production apparatus comprising: i 5 at least one channel open at is upper side to receive a seed mass, said channel having a Sbase; an inlet supply for irrigating the channel with a nutrient solution; an outlet downstream of the inlet supply means for draining the channel; and means for controlling the temperature and humidity within the enclosure between pre- 0 determined values to prevent rotting of the seed mass.

2. The seedling production facility as claimed in claim 1, wherein the inlet supply is arranged to distribute nutrient solution directly into the base of the channel.

3. The seedling production facility as claimed in claim 1 or claim 2, wherein the inlet supply distributes the nutrient solution across the width of the channel.

4. The seedling production facility as claimed in claim 1, wherein the inlet supply is arranged above the base of the channel such that the inlet supply is above a seed mass received in the channel in use. P.XOPER1XC2IX)9%3(j723156 -ddoe.23A)2J2OM" -21 A seedling production facility as claimed in any one of claims 1 to 4, wherein the inlet supply is arranged to distribute the nutrient solution as a film flowing along the base of the channel.

6. A seedling production facility as claimed in any one of claims I to 4 wherein the outlet is closable to flood the channel and openable to subsequently drain the nutrient solution from the channel.

7. A seedling production facility as claimed in any one of claims 1 to 6, wherein the 0 temperature and humidity within the enclosure is controlled by an air-conditioning system.

8. A seedling production facility as claimed in claim 7, wherein the air-conditioning system is a reverse cycle air-conditioner.

9. A seedling production facility as claimed in any one of claims 1 to 8, wherein the ambient temperature within the enclosure is controlled within the range of substantially 20 to 22 degrees Celsius. A seedling production facility as claimed in any one of claims 1 to 9, wherein the relative humidity within the enclosure is below

11. A seedling production facility as claimed in any one of claims 1 to 10, wherein the relative humidity within the enclosure is substantially P OPER XC2IX)9()72 3I56 di,.dC-23A)2/21X9 -22-

12. A seedling production facility as claimed in any one of claims 1 to 11, wherein the enclosure is thermally insulated.

13. A seedling production facility as claimed in any one of claims 1 to 12, wherein the enclosure has restricted natural light access to prevent excessive internal heating of the enclosure.

14. A seedling production facility as claimed any one of claims 1 to 13, wherein the channel 0 is inclined in the longitudinal direction of the channel to promote the flow of the nutrient film solution from the inlet supply to the outlet. A seedling production facility as claimed in any one of claims 1 to 14, wherein the channel has a gradient of substantially 1:30 in the longitudinal direction of the channel from the inlet supply to the outlet.

16. A seedling production facility as claimed in any one of claims 1 to 15, wherein the depth of the channel is sufficient to receive a seed mass at least substantially 5mm deep and no more than substantially

17. A seedling production facility as claimed in any one of claims 1 to 16, wherein the apparatus seedling production facility further comprises a capillary medium arranged on the base of the channel and configured to support the seed mass. I P XOPER\MX02M90i0723156 di,.d.-23I)22(X9 -23

18. A seedling production facility as claimed in any one of claims 1 to 17, wherein the inlet supply is provided at one end of the channel, a further inlet supply is provided at the other end of the channel, the outlet is provided in a part of the channel intermediate the inlet supply and the further inlet supply, and the channel is inclined downwardly from each of its ends towards the outlet.

19. A seedling production facility as claimed in any one of claims 1 to 18, wherein the inlet supply is arranged to continuously irrigate the seed mass with the nutrient solution to provide a continuous flow along the base of the channel. 0 A seedling production facility as claimed in any one of claims 1 to 18, wherein the inlet supply is arranged to periodically irrigate the seed mass with the nutrient solution.

21. A seedling production facility as claimed in any one of claims 1 to 20, wherein the flow of the solution is controlled by a dosing unit.

22. A seedling production facility substantially as hereinbefore described with reference to the accompanying drawings. DATED this 3 'd day of November 2003 PETER DOYLE CONSULTANCY PTY LTD By its Patent Attorneys: DAVIES COLLISON CAVE