AU2004201547B2 - Tray container for use with cuttings - Google Patents

Description

Rurlntin 3,2 AUSTRALIA Patents Act 1990 COMPLETE SPECIFICATION FOR A STANDARD PATENT (ORIGINAL) Name of Applicant: Transplant Systems Limited Actual Inventor Alan Rogers Address for Service: DAVIES COLLISON CAVE, Patent Attorneys, 1 Nicholson Street, Melbourne, Victoria 3000. Invention Title: Tray container for use with cuttings Details of Associated Provisional Application No: 2003903182 Date: 23 June 2003 The following statement is a full description of this invention, including the best method of performing it known to us: Q.OZ~pZOSU~ay~s 09 do. L4M4 TRAY CONTAINER FOR USE WITH CUTTINGS Field of the Invention The invention relates to container for use with cuttings of plants, such as pine. 5 Background oft. invention Radiata pines have been grown for many years from seed collected from existing plantations. Higher value seed was obtained by selected superior trees (those trees having desirable properties) and obtaining seed from them, to form a new plantation from the 10 superior stock. An obvious problem with the seed production practice was the lack of control over the second parent (the pollen parent). A technique used to reduce this problem included planting the seed stock plantations a long distance away from the commercial production 15 plantations. Another technique involved shielding the mother cones and the application of preferred pollen to those cones. There are now a number of well established breeding lines having a range of desirable properties. However, there are typically delays of 2 to 5 years between planting the seed 20 and providing the trees for the first commercial distribution. There was a significant problem in commercialising new plant varieties due to the delay in producing commercial quantities of the new variety of the pine. With the new techniques for breeding and manipulation, it is possible to quickly produce new breeding lines and high speed propagation and deployment methods are required to shorten the delay in the production of 25 commercial quantities of a new variety. Fortunately, it was found that pines could be propagated by cuttings. This has allowed the use of clonal forestry methods for the rapid production of commercial quantities of new species. 30 The most commonly used cutting system is the bare-root method. Large areas of plants (the mother plants) are maintained in the field in permanent hedges. Each can supply between 20 to 50 field sized cuttings a year and normally last for about five years before needing to be replaced. The cuttings are planted out into growing beds and grow into 5 seedlings which are subsequently lifted which bare roots the plant and the root system is pruned back to 3 or 4 main roots having a desired root structure before planting out in a plantation. There are a number of significant disadvantages with this method including the need for 10 large amounts of land for growing the hedges and the cuttings lifted therefrom. The lifting and planting of the cuttings are normally done during winter and at the same time by all of the plantation managers and as such there is typically casual staff shortages. In addition, the weather and overall work conditions can be unpleasant as the lifting and planting is done working on hands and knees. is A variation of this technique is to take a second set of cuttings later in the year. The second set is generally too small for field planting but has been used in Chile, by setting the cuttings in containers. The cuttings are grown in unheated greenhouse conditions, and subsequently outside without cover: This can provide an extra 20 cuttings per hedge plant 20 per year. Another variation Is to regularly collect cuttings over winter from the hedge plants and set the cuttings in containers on outdoor racks for rooting and growing. Only a few cuttings are taken at each picking. 25 Intensive hedge propagation is a method used for quickly propagating selected types of hedge plants. Seeds are sown into containers and grown in a greenhouse. A single cutting is taken from the tip and is planted into another container. The mother plant responds to the topping by producing 2 or 3 new tips, each over which can be harvested and rooted. 30 The next cycle of tipping can produce between 5 to 10 cuttings. It is possible to produce about 80 plants per year from a single seed. The propagated plants may then be planted -3 out into hedge rows to become the source of field cuttings as per the bare-root method. A variation of this used in Chile involves topping the tooted cuttings to produce 100 to 136 hedge plants per year from a single seed. 5 The use of containers and 'containerised' plants in plant growing methods has been found to provide a number of advantages. Containerised plants grow at a faster rate than those in the field as the growing environment is under better control than a bare-root nursery. Even when the plants are grown outside, containerisation can provide greater control over growing conditions as it allows the plants to be moved as required. Furthermore, 10 containerised plants can be suitable for plug planting, where the plant is transplanted into the ground whilst still in a plug of the growth medium from the container. A commonly held rule of thumb is a plug planted containerised plant will perform similarly to bare-root plant of twice its root diameter and as such can be planted out sooner than the bare root plant. The bare-root method requires the plants to be lifted from a growing bed, growth 15 medium removed and the roots pruned back to 3 or 4 main roots. This shocks the plant and sets-back the growing cycle. Containerisation can also provide better working conditions for the workers, particularly when combined with an appropriate overall plant management system. The containers can 20 be positioned at waist height on tables, reducing the need for the workers to bend over and reducing the need to work with permanent hedge rows, lifting, grading and packing plants and the problems it can cause. However, there are problems with using containerised propagation methods with cuttings 25 such as Pinus radiate, because the cuttings produce strong, aggressive root shoots. The roots of seed grown plants will typically grow out downward with one or more substantially downwardly growing roots, such as a taproot. Smaller roots typically grow outward from the sides of the main downwardly growing root(s). However cuttings, such as those of Pinus radiata, tend to have a shoot root which grows laterally outward from the 30 side of cutting with limited downward growth. The shoot roots need to be turned downward and this can occur when the roots contact the side of the container. However, -4 the roots tend to grow in a spiral, downward along the container wall and this will result in the plant having poor root development. This limits the use of containerised techniques with cuttings of Pinus radiata and other 5 plants with similarly strong, aggressive root shoots particularly for timber plantations because of the need for a good-root structure to encourage improved field anchorage and rapid uptake of surrounding nutrients following planting. It is accepted that the root growth of container-grown plants after being transplanted primarily involves extensions of existing roots rather than the development of new roots. Consequently, the number and 10 position of the root tips of the containerised plant will have a significant influence on the growth and development of the transplanted plant Containers have been developed to try to control spiral root formation with seed grown plants. The containers may omit a bottom and incorporate one or more vertical slits 15 therein to facilitate air pruning of the roots in a desired orientation. Examples of such containers and methods of use can be found in US 4,753,037. It provides a container having a plurality of substantially horizontal internal ledges having holes at lower points therein. The roots of a seed grown plant will grow outward and downward until they contact the base of the container and be directed out via a hole. Upon extending through a 20 hole, the root tip is air-pruned, whereby the portion of the root extending out of the hole is killed by desiccation. Other similar containers are described in US 4,389,814; US 5,678,356; US 5,557,889 and US 6,385,903. These described variations in trays of containers (also known as plug trays) 25 for growing plants from seed. Useful features include having the same centre-to-centre spacing between all adjacent containers in the tray to facilitate machine planting and handling, having tapered sides, aeration holes, vertical air-pruning slots in the side of the containers and a hole at the bottom of the container. 30 However, such containers are intended for use with seed grown plants and are generally not appropriate or suitable for use with cuttings with strong or aggressive shoot roots, such -5 as Pinus radiata cuttings, particularly when the containerised plants are intended to be planted out into the field in plugs. Summary of the invention 5 In accordance with a first aspect of the present invention, there is provided compartment for use with a plant cutting, the compartment having a top opening and a smaller bottom opening, with the distance between the openings defining the depth of the compartment, each compartment having an internal wall, wherein at least a section of the wall is tapered towards the bottom opening, the internal wall including a plurality of root guides, 10 each guide comprising a downwardly orientated ridge and a lateral wall segment that extends along at least a portion of the ridge at or near the apex of the ridge, the internal wall of each compartment also including a plurality of downwardly orientated elongate slots, the slots being located between the apexes of ridges and widening as they extend towards the top opening. 15 In accordance with a second aspect of the present invention, there is provided a tray including a plurality of growing compartments as described above, wherein the top opening of each compartment is located in the top surface of the tray. 20 The root guides should be capable of guiding root tip growth of cuttings so as to reduce root spiralling such that the roots grow towards the slots or downward towards to the bottom opening of the compartments. Preferred embodiments of the invention also relate to the compartments used in the tray 25 and the use of the tray or a compartment in controlled propagation systems, particularly with plant cuttings, and to a method for producing plants having a root-form suitable for planting directly into plantation from compartments by planting cuttings into compartments as described above. 30 For clarity, "downwardly orientated" is any direction from the top opening of a compartment towards the bottom opening of the compartment. If the surface of the tray defines horizontal plane, then downwardly orientated includes in a direction from the top -6 opening towards the bottom opening along an axis perpendicular to the horizontal plane. It also includes axes at other angles but still having a significant vertical component, ie ±35 degrees from the perpendicular axis extending below the horizontal plane, preferable *25, more preferably ±15. It also includes and is preferably limited to the direction most 5 directly downward along the surface of the internal wall (depthwise). This can be the route that provides the shortest distance down the internal wall between any point from the top opening to the bottom opening. This is the most preferred orientation of the ridges, and in particular the apex of the ridges, wall segments and the elongate slots in the compartment, 10 The design of these compartments should reduce root spiralling and provide a plant with a healthy combination of laterally extending roots (air pruned) and downwardly extending roots. It should avoid the earlier need to use bare root production methods with Pinus radiata seedlings and cuttings in order to provide a desired root structure. 15 The internal wall of the compartment should have a shape which will permit the plant and any plug of growth medium to be pulled out of the compartment. Accordingly, the inner surface of the wall includes a taper, in at least in a section of the wall, from the larger top opening to the bottom opening. The taper can facilitate the upward removal of the plant and plug of grow medium from the compartment through the wider top opening. The taper 20 does not need extend along the depth of the compartment. Preferably the inner surface of the compartment may taper from at or near the top opening down to the lower opening. Thus the inner surface of the wall may include an upper substantially non-tapered section (a collar) extending from the top opening to an intermediate depth near the top opening and a tapered section extending from the intermediate depth to the bottom opening. The upper 25 section may itself be wholly non-tapered with a constant horizontal cross-section or substantially non-tapered. For example, a substantially non-tapered upper section may have a slight taper towards the intermediate depth, such as less than 1* off the vertical. Preferably, the taper, if any, in the upper (non tapered) section is less pronounced than the taper in the other (tapered) section. In such an arrangement the ridges preferably start at or 30 near the start of the tapered section (ie at or near the intermediate depth) and extend the depth of the compartment to the bottom opening.

-7 Preferably, each compartment has an upper, substantially non-tapered collar portion, which comprises from 15 to 30% of the total depth of the compartment, more preferably 20 to 25% and more preferably about 22%. When the compartment has a total depth of 110 mm, it is preferred for the collar portion to comprise the uppermost 25 mm of the compartment. 5 The internal wall may alternatively provide a single tapered section having the same angle of taper for the depth of the compartment. In that arrangement the ridges may start at or near the top opening or may start at an intermediate depth and extend to the bottom opening. 10 The inner surface of the compartment also includes wall segments at or near the apex of the ridges. The wall segments preferably extend I to 3 mm out from the surface. The wall segments preferably extend. along the apex of the ridges down the inner surface. The segments may extend the depth of the compartment, beyond the ridges along the wall up to 15 or near the top opening. It can be advantageous not to extend the ridges all the way to the top opening as it may cause difficulties in nesting or stacking trays of the invention together. The plurality of downwardly extending ridges and segments thereon in the compartment 20 can provide a plurality of 'channels' in the compartment wall. Those roots growing outward may either grow directly into the channel or may also be guided by the surface of a ridge deep into a channel. It is thought that once the growing root shoot is located between the ridges, the slope of the adjacent ridges should reduce the likelihood that the root will grow in a spiral around the side of the compartment. Those root shoots that 25 persist in growing towards the top or apex of the ridges may contact the downwardly extending wall segments, located at or near the apex of the ridges, which can act as a further barrier to spiral root growth. The channels should redirect the root growth downward or back into the same channel. 30 As it is preferable to also include laterally orientated roots then the compartment should include downwardly orientated elongate slots in some of the channels. The ridges can guide the root shoots towards a slot or slots located within channels, where the root is air pruned and, after the plant is transplanted, growth can occur from the air pruned ends of the roots. It is preferred to include a mixture of channels with and without the elongate slots, as this 5 can provide a mixture of outwardly growing and downwardly growing roots. This arrangement tends to produce plants with healthy root structures, even from cuttings. A preferred means of doing this is to locate the slots in alternate channels. The root shoots in a channel without a slot may be directed to grow downward to eventually be pruned at the bottom opening, and those root shoots in the adjacent channel may be guided into the slots 10 to provide air pruned roots that will grow outward. Alternatively, slots may be located within each channel, but at different depths of the compartment in order to provide a mixture of laterally and downwardly orientated roots. 15 The slots are preferably located in a portion of wall located between ridges. Alternatively, the slots may be located at or near a lower portion of the ridge, such as in a trough formed between two adjacent ridges. Preferably, the wall immediately around to the slots should be tapered from the inside of 20 the compartment to outside, in order to guide roots growing around the wall into the slot. Preferably the upper edge of the slot is also tapered to provide a downward facing cutting edge capable of severing plant roots when a plant is being removed from the compartment. This feature can facilitate the removal of a plant from a compartment by reducing the 25 likelihood air pruned roots extending out of the slot will jam in the slot as the plant is removed. Preferably, each compartment has four slots, each slot being regularly spaced about the wall and only located. between ridges. 30 Preferably each compartment has four regularly spaced corner root guides, located at or near opposed corners of the compartment and each guide comprises a downwardly -9 orientated ridge having at or near its apex a downwardly orientated wall segment which laterally projects towards a central vertical axis of the compartment. Preferably the compartment additionally has four wall root guides, each guide including a 5 downwardly orientated ridge in a non-corner part of the wall, the ridge having at or near the apex, a laterally projecting downwardly orientated wall segment, the wall ridges being regularly spaced about the wall. Preferably, the wall root guides located on opposite sides of the compartment are offset with each wall guide located between two adjacent corner guides and located closer to one of the pair than the other, 10 This arrangement can provide several advantages. It can provide a larger wall section between a corner root guide and one of the adjacent wall root guides into which an elongate slot can be located, allowing a wider slot to be used. It can also offset the slots, which is advantageous when a plurality of the same compartments are regularly located 15 about the tray, in an array of columns and rows, with each compartment in the same orientation as the compartments located adjacent to it. This is because the slots of each compartment are offset from the slots of the compartments located in the adjacent columns and rows. This reduces the likelihood roots extending out of a slot of one compartment will get entangled with roots extending out of the slot of an adjacent compartment, This 20 improves the ease by which plants can be removed from compartments and also facilitate the closer packing of compartments. Such an arrangement can also allow for machine processing of the trays, the compartments therein, and the plants, as it permits a regular spacing. of compartments in trays. 25 Preferably, all of the ridges, wall segments and slots of the compartment extend directly downward along the internal wall. Preferably, all wall segments of the compartment extend along the apex of each of the ridges. 30 Preferably, the wall segments of the compartment extend from 1 to 3mm from the surface of the ridges.

- 10 It is preferred for the trays to have a shape which facilitates nursery machine handling. Preferably the tray has a pair of opposed sides and a pair of opposed ends, the length of the opposed sides and opposed ends of the tray are all substantially the same. Preferably, the 5 compartments are all of substantially the same shape and same orientation in the tray and are regularly located within the tray in an array of rows and columns. Preferably the rows of compartments within the tray are substantially parallel to the opposed ends and substantially perpendicular to the opposed sides. Preferably the columns 10 of compartments within the tray are substantially parallel to the opposed sides and substantially perpendicular to the opposed ends. Preferably each compartment has a central vertical axis and the axes are regularly located about the tray so the centre-to-centre distance between growing compartments in adjacent 15 rows and adjacent columns is substantially the same. Preferably the centre-to-centre distance is of from 40 to 55 mm, more preferably of from 45 to 50 mm, most preferably approximately 48 mm. The preferred density of compartments is important as it should provide a commercially 20 acceptable tray. If the number of plant cuttings per tray is too high this can reduce the amount, size and quality of foliage. If the number of plant cuttings per tray is too low the individual plant cuttings should be larger and better developed but the tray may cost too much to manufacture and may not be commercially acceptable. 25 Preferably the tray has from 300 to 450 compartments per square metre, and more preferably 330 or 432 plants per m2. Preferably each compartment has a volume of from 100 cm 3 to 150 cm 3 , more preferably of from 110 cm 3 to 140 cm 3 , most preferably approximate 125 cm 3 . 30 - 11 Preferably, the depth of each compartment is from 95 to 125 mm, more preferably from 105 to 115 mm and most preferably approximately 110 mm. The top opening is preferably from 37 to 50 mm across, more preferably from 37 to 48 mm 5 across, more preferably from 40 to 45 mm, most preferably around 42 to 43 mm. The bottom opening is preferably from 20 to 30 mm across, more preferably from 23 to 27 mm, and most preferably 25 mm across. A preferred density of compartments per tray can be achieved by having a 7 x 7 array or 8 10 x 8 array of compartments having the above dimensions and spacing in a square tray having a width of from 370 mm to 400 mm, preferably from 380 mm to 390 mm, most preferably approximately 385 mm. Preferably, the compartments are regularly spaced about the tray in rows and columns. 15 Depending on the medium used in the compartments it may be necessary to include a restraint across the bottom opening, but for others the tapered shape should prevent the medium falling out of the bottom. However, in order to be useful with range of mediums, it is preferred that each compartment in the tray include a growing medium restraint at 20 bottom opening. Preferably the restraint bridges across the bottom opening. Preferably, the upwardly facing surfaces of the restraint are inclined so as to direct the root tip of any downwardly growing roots to either side of the restraint. It is also preferred to taper any wall segment into its ridge, if the wall segment would otherwise have been close to the bridging restraint in order to avoid roots from getting caught between the segment and the 25 restraint and interfering with the removal of the plant from the compartment. It may also serve to improve the strength of the connection between the restraint and the wall. Preferably the tray also includes a plurality of aeration apertures in the top surface of the tray. When the compartments are set out in the tray in a regular array, it is preferred to 30 locate an aeration aperture in the top surface of the tray, in the region between four adjacent compartments.

- 12 Brief Description of the Drawings Non-limiting preferred embodiments of the invention will now be described in detail with reference to the accompanying drawings in which: 5 Figure 1 is a plan view of a tray in accordance with a preferred embodiment of the present invention. The tray includes 64 growing compartments. Figure 2 is a side view of the outer surface of the tray of figure 1 in the direction of the arrow A. 10 Figure 3 is a side view of the outer surface of the tray of figure 1 in the direction of the arrow B. Figure 4 is an enlarged section view of a compartment of figure 1. 15 Figure 5 is a view from above of a cross-section through line 5-5 of a compartment of figure 4. Figure 6 is a perspective view from below of the tray of figure 1. 20 Figure 7 is a perspective view from above of the tray of figure 1. Figure 8 is a perspective view from above of an alternative embodiment of a tray according to the present invention. 25 Figure 9 is a perspective view from below of an alternative embodiment of a tray according to the present invention. Figure 10 is a perspective view from below of another alternative embodiment of a tray 30 according to the present invention. Figure 11 is a perspective view from below of a further alternative embodiment of a tray according to the present invention. 35 Detailed Description -13 A tray in accordance with a preferred embodiment of the invention is shown in figures 1 to 7. The tray (10) is substantially square. The tray is intended for use with pine cuttings. All sides have an approximate length of 385 mm. The tray includes an 8 by 8 array of substantially identical compartments (20) therein. Each compartment has substantially the 5 same shape as the other compartments, substantially the same alignment and is regularly spaced about the tray in rows and columns. This combination of features can facilitate machine handling of the trays. The tray includes apertures (12) between compartments for use in aerating the plants. 10 The compartments are integral with the tray, the overall tray preferably being formed by injection moulding. The compartments have a top opening (22) located in the top surface of the tray (24). The 15 compartments have a smaller bottom opening (26) and a wall (28) between the top and bottom openings, having an inner surface (30) and an outer surface (32), For use with radiata pine, each compartment has a volume of approximately 125 c/c, a depth of 110 mm, the top opening is approximately 42.5 mm wide when measured across 20 the sides, the bottom opening is 25 mm wide across the sides. The tray provides 432 compartments per m 2 at a central axis (34) and a centre-to-centre distance (34) - (34) between adjacent compartments (row or column) of 48 mm. The compartments have an uppermost section (36) and a tapered section (38). The 25 uppermost section can be described as a non-tapered section although in fact it has a slight taper (less than 10 off the vertical) towards the bottom opening. For use with radiata pine, the overall compartment has depth as measured along a vertical axis of 110 mm, with the non-tapered section (36) being 25 mm in depth and the tapered section (38) being 85 mm in depth. Wall segments (40), (42), (44) laterally project approximately 1-2 mm from the 30 wall and extend directly downward, depthwise (from the top opening to the bottom -14 opening) along the wall. In the non-tapered section the portion of the wall segments therein (40) laterally projects from the wall surface. The wall segments continue depthwise in the tapered section as segments (42) and (44), but project from the apex of depthwise orientated ridges (46), (48) located in the wall. Near the bottom end of the 5 compartment, the wall segment (44) tapers into the wall near the bottom opening at (45) where it nears a growth material restraint (50) which bridges across the bottom opening. The upper surface of the restraint (52) is inclined to direct any roots to either side of the restraint. 10 Various designs can be used for the growth material restraint. Figure 8 and 9 show alternative bridging restraints (54) and (56). Continuing with Figures 1 to 7, the wall segments (42) are located at the apex of corner ridges (46) and together provide four corner root guides. The wall segments (44) are 15 located at the apex of wall ridges (48) which together provide four wall root guides regularly spaced about the wall. The wall root guides are located closer to one of the adjacent comer guides than the other. This provides eight depthwise extending channels, four narrow channels (60, 61, 62 and 20 63) and four wider channels (64, 65, 66 and 67). The narrow channels are defined by the sides of two adjacent ridges (69, 71), the wall segments thereon and wall there between (if any). Towards the top opening there is a flat wall surface (70) between the adjacent wall and corner ridges. As the wall tapers in towards the bottom opening the distance between the ridges decreases until the ridges come into contact with each other near the bottom 25 opening. The wider channels are defined by the region from the one side of a wall segment, the same side of the ridge to which the segment is attached (72), a flat wall surface (74), the side of another ridge adjacent to the same wall surface (76), and the side of the wall 30 segment on the ridge.

- 15 The wider channels include tapered elongate slots (80) for air pruning lateral roots in the wall (74) between the two ridges. The slot is tapered towards the bottom opening, narrowing as the width of the wall between adjacent ridges decreases. The edges (82, 83) of the slot are tapered outwards to facilitate root growth out of the slot for air pruning. The 5 top edge (84) is also tapered to provide a knife edge. As can be seen from figure 1, the slots of adjacent compartments are offset from each other. This reduces the likelihood of having the roots of adjacent plants grow into each other and entangle, thereby making it difficult to remove the plants from the tray. For 10 those few roots that might entangle, the knife edge at the top of the slots should sever those roots when the plant is removed. This arrangement of offset slots also allowed a higher density of compartments in the tray, without excessive entanglement of roots. 15 The tray of figure 8 is very similar to the tray of figure 7, but the wall segments (86) at the corners of the compartment start at a position set back from the top opening in the non tapered portion of the compartment. This arrangement has been found to permit the trays to be stacked or nested within other trays without the wall segments of a tray contacting 20 and binding on the outer surface of the compartments of tray nested within. The wall segments (87) start from the top opening as they do not interfere with the nesting of trays. The slots in the trays may alternatively be rectangular, such as the slots (90) shown in Figures 9 to 11. However, like the first described trays, the edges of these slots are tapered 25 outwardly and the top edge should be blade like, The relative dimensions of the compartments and tray may be altered to suit particular types of cuttings, or to improve plant sizes. The tray of figure 11 has the side lengths as the earlier tray, but has less compartments, 49 instead of 64. As a consequence the size, 30 volume and centre-to-centre distance between compartments has been increased. The plants in such a tray would have more space to grow and thus the plants can have improved - 16 growth and development. Such trays may be used with more valuable cuttings or less hardy plants where increased value of older or larger plants makes the growth of such plants economic despite the overall reduced yield per square metre. 5 It would be appreciated by a person skilled in the art numerous variations and/or modifications may be made to the embodiments of the invention as shown without departing from the spirit or scope of the invention as broadly described, The present embodiments are, therefore, to be considered in all respects as illustrative and not restrictive. 10 For example the trays may be rectangular in shape as this may be useful with some nursery machines. The shape of the compartments may vary from that specifically described. For example the compartments may be substantially circular, rectangular, octagon or irregular in shape. The tray may include a mixture of two or more different shaped compartments, 15 Throughout this specification and the claims which follow, unless the context requires otherwise, the word "comprise", and variations such as "comprises" and "comprising", will be understood to imply the inclusion of a stated integer or step or group of integers or steps but not the exclusion of any other integer or step or group of integers or steps. 20 The reference to any prior art in this specification is not, and should not be taken as, an acknowledgment or any form or suggestion that that prior art forms part of the common general knowledge in Australia and New Zealand.

Claims (20)

1. A compartment for use with a plant cutting, the compartment having a top opening and a smaller bottom opening, with the distance between the openings defining the depth 5 of the compartment, each compartment having an internal wall, wherein at least a section of the wall is tapered towards the bottom opening, the internal wall including a plurality of root guides, each guide comprising a downwardly orientated ridge and a lateral wall segment that extends along at least a portion of the ridge at or near the apex of the ridge, 10 the internal wall of each compartment also including a plurality of downwardly orientated elongate slots, the slots being located between the apexes of ridges and widening as they extend towards the top opening.

2. The compartment of claim 1, wherein the plurality of downwardly extending ridges 15 and wall segments thereon located about the internal wall provide a plurality of downwardly extending channels for guiding root growth downward and for reducing or preventing root spiralling around the internal wall of the compartment.

3. The compartment according to claim 2, wherein the downwardly orientated 20 elongate slots are located in at least some of the channels.

4. The compartment according to any one of claims 1 to 3, wherein the internal wall immediately around the slots is tapered to guide roots growing around the wall into the slot. 25

5. The compartment according to any one of claims 1 to 4, wherein an upper edge of each slot is tapered to provide a downward facing cutting edge capable of severing plant roots extending through the slot when a plant is removed from the compartment. 30

6. The compartment of any one of claims 1 to 5, comprising regularly spaced corner root guides, located at or near opposed corners of the compartment, wherein each guide - 18 comprises a downwardly orientated ridge having at or near its apex a downwardly orientated wall segment.

7. The compartment of any one of claims 1 to 6, which comprises wall root guides, 5 each guide including a downwardly orientated ridge in a non-corner part of the wall, the ridge having at or near the apex, a downwardly orientated wall segment.

8, The compartment of claim 7, wherein the non-corner ridges are regularly spaced about the wall. 10

9. The compartment of claim 7 or 8, wherein the wall root guides on opposite sides of the compartment are offset.

10. The compartment of any one of claims 7 to 9 as appended to claim 6, wherein the 15 compartment comprises four corner root guides, four wall root guides and four elongate slots, with each wall guide located between two adjacent corner guides and located closer to one of the corner guides than the other corner guide, and each slot is located between the wall guides and the other corner guide, the guides and slots being regularly located about the compartment. 20

11. The compartment according to any one of claims 1 to 10, wherein the compartment has a substantially non-tapered internal wall section extending from the top opening to an intermediate depth near the top opening, and a tapered wall section extending from the intermediate depth to the bottom opening. 25

12. The compartment according to any one of claims 1 to 11, wherein the ridges start at or near the start of the tapered section of the internal wall and extend down the wall to or near the bottom opening. 30

13. The compartment according to claim 12, wherein the wall segments extend beyond the ridges and laterally project from substantially non-tapered section of the internal wall. - 19

14. The compartment according to any one of claims 1 to 13, wherein at least some of the wall segments do not extend to the top or bottom openings. 5

15. A compartment for use with a plant cutting, substantially as hereinbefore described with reference to the drawings and/or Examples.

16. A tray including a plurality of growing compartments according to any one of claims 1 to 15, wherein the top opening of each compartment is located in the top surface 10 of the tray.

17. Use of the compartment or tray of any one of the preceding claims, in controlled propagation systems. 15

18. The use according to claim 17, to grow Pinus radiata cuttings.

19. A method of growing plants from cuttings, the plants having a root-form suitable for plug planting, by growing the plants in compartments according to any one of claims 1 to 15 or in compartments in a tray according to claim 16. 20

20. A method of growing plantation timber which includes the step of plug planting seedlings grown in compartments according to any one of claims I to 15 or in compartments in a tray according to claim 16.