GB2350272A

GB2350272A - Plant root container

Info

Publication number: GB2350272A
Application number: GB9710420A
Authority: GB
Inventors: Suzanne Wallace Single; Caledonian Tree Company Li The
Original assignee: CALEDONIAN TREE Co Ltd
Current assignee: CALEDONIAN TREE Co Ltd
Priority date: 1997-05-22
Filing date: 1997-05-22
Publication date: 2000-11-29
Also published as: GB9710420D0

Abstract

The container comprises a flexible strip of material 1 which has truncated cone recesses 6 formed therein. The recesses have an aperture 7 to guide roots to the outside of the container. The recesses correspondingly form protuberances on the external surface to of the strip 1 and these interlock so that the ends of the strip 10, 11 can form the container. The strip may form a cylindrical container that is fixed in place by a clip (fig 6) or other fastener. The container may have a base 18 which may be coated with a root-deterring substance 27. In use as the plant grows the strip can be unclipped to form a larger container.

Description

2350272 AIR ROOT PRUNING, PLANT PRODUCTION CONTAINER.

This invention relates to an air root pruning, plant production container, and more specl f ically, to containers suitable for growing plants which are to be transplanted into the ground at some future time.

The word "plant" as used throughout this specification is to be understood as embracing all fOrms of plant life, including trees, shrubs and other plant life gro,ii for commercial sale, having a root structure which extends at least during the early stages of'growth of the plant.

The first obJective of the invention to provide a container for above ground plant growth which is easily adaptable in diameter, is reuseable and does not require a base.

The second objective of the invention to provide the container described in tile first objective with a base adequate to support a load within the container. A further objective o('the invention is to provide a base which controls the downward extension of' the root growth of a plant within a container of this kind.

According to the first aspect of the invention a container is comprised of a flexible strip of material having a length greater than its width and having an inner and ail outer Surface, said inner surface being formed in part by a lattice of root guiding recesses or inner cusps, at least some of said recesses being of substantially truncated conical form having a wall which converges towards a hole through the strip. said outer stirl'ace being formed in part by a lattice of protruberances or outer cusps at the same relative positional arrangement as the recesses, said strip arranged in a cylinder with its opposite ends overlapping, nested engagement. It is further preferred that the side wall or side walls of the container be releasably connected so as to enable the container to be dismantled or adjusted to have a different lateral extent.

According to the second aspect of the invention a base can be provided which is suitable for use with a plant container, said base being capable of supporting a load within the container. In a preferred form, that base also functions to control the downward extension of root growth by coating the inside surface of said base with chemical grow-th retardant. It is further preferred that the base is releasably connected to the side wall or side walls of the container so as to enable the container to be dismantled.

The invention extends to a method of growing a plant using a container of the invention.

A particular feature of this container is the side wall arrangement which promotes air pruning of the expanding root structure. The arrangement is such that laterally extending roots are directed towards openings of restricted size formed through the container walls.

1 The root growth which extends to the openings is air pruned in a known manner, thus causing secondary roots to form. The secondary roots repeat the same growth and air pruning process. The arrangement of the invention in this form allows the container to be ofvarlable diameter and volume.

Another 1CatUre of this container is to provide a base adequate to support a load situated within the container.]'his feature allows the container to be used within existing plant nursery operating procedures and to be readily transported with the load in place.

A further feature of this container is to provide a base which has been treated with a chemical growth retardant. Any root growth which extends down to the base is pruned by the copper based compound also causing secondary roots to form. These secondary roots repeat the sarne growth and chemical pruning process. This feature also allows the container to be used within existing plant nursery operating procedures and to be readily transported with the load in place.

The rootsystem obtained from a container willi or without a base, forms a well matted and cohesive root ball which is ideal for transplantation.

An embodiment of the invention is described in detail in the following passages of the specification which refer to the accompanying drawings. The drawings are however, merely illustrative of how the invention might be put into effect, so that the specific form and arrangement of the various features as shown is not to be understood as limiting on the invention.

In the drawings: Figure 1 shows a side elevation view of a strip of material according to one aspect of the I IIVCI1t1011 Suitable for forming a container in whicli a plant may be grown; Figure 2 shows a container of-the type which is formed by a strip as show]] in figure 1. Figure 3 shows an enlarged perspective view of a portion of the strip of material shown in figure 1 Figure 4 shows a sectional view along line IV- 1V of figure 2. Figure 5 shows a sectional view along line V - V of figure 2. Figure 6 shows a fastener Clip. Figure 7 shows a plan view of the container shown in figure 2 with a smaller diameter, suitable for a base. Figure 8 shows a container at a larger diameter for use without a base. Figure 9 shows a perspective view of the container as shown in figure 7 with a base located Rear the bottomand the clip fixing. Figure 10 shows a cross-section of the container as shown in figure 9 with a base located near the bottornand showing the chemical retardant application.. Figure 11 shows a side sectional view of a sapling growing in a container without a base according to the invention. Figure 12 shows a side sectional view of a sapling growing in a container A11h a base according to the invention.

The present linvention is particularly concerned with the growth of plants, SLIclI as trees and slii-Libs, in above ground containers prior to the plants being transplanted into the ground.

The niain aiins of the invention are:

To provide containers of which guide primary roots radially outwardly towards holes in the container walls. As the roots approach the holes they are air pruned rCSLIItIn,I,I in secondary roots branching from the length of the primary roots and Z- tlicreby I'Orining a well matted and cohesive root ball which is ideal for transplantation.

To provide a base of various fixed diameters to the containers which allow free movement of the container during the production time of the plant and assist in promoting root development by chemically controlling downward root grovv'th.

As shown in Figures I and 2, a strip I of material is shown having an inner surface 2 and an oLiter surface 3. The strip is preferably formed of a relatively thin thermoplastic sheet material 4 which is rollable or bendable into a circular cylindrical container 5 as shown in Figure 2. The sheet material is sufficiently rigid and strong so that when formed into an open topped cylindrical container 5 as shown in Figure 2. the container 5 is self supporting and is able to be filled with a growing medium, such as soil or humus or the like.

The strip I has been plastically distorted or contoured as shown in Figures 3 and 4 so as to provide a lattice of root guiding recesses 6 therein. The root guiding recesses eacli lead towards a hole 7 througli the strip resulting in a lattice of holes 7 over the entire surface ofthe sheet. Any suitable recess 6 is substantially conically shaped tapering outwardly towards the respective hole 7 to which it leads. It is not essential that each recess 6 leads towards a respective hole 7. but this is the preferred arrangement.

The sheet material 4 shown in Figure 3 of the drawings depicts the form of the sheet in more detail. As shown, and as viewed from the outer surface side 3, the sheet 4 is formed by distorting the sheet alternatively inwardly and outwardly in a grid pattern to form a grid of truncated conical peaks 8 and truncated conical recesses 9, the peaks and recesses alternating in both the horizontal and vertical directions. Since the sheet 4 is thin, a peak on the outer surface 3 will form a recess 6 on the inner surface 2, and vice versa, and accordingly the form of the outer surface will be substantially inversely identical to the form of the inner surface. The tip of each peak 8 (as viewed from the outer surface) has been removed or slit to form the holes 7 through the sheet. Thus. when viewed from the inside, each recess 6 is of conical form and leads towards a hole 7 through the sheet.

Y Since the inner surface 2 is the)iiverse shape of the outer surface 3 tile ends 10.11 of the strip 7 can be overlapped as shown in Figure 2 so that, at the overlap 12, the peaks 8 on the outer surface of one end 10 nest within the recesses 6 on the inner surface of' the other end 11.

When the ends 10, 11 are in their overlapped condition, as shown in detail in Figure 5, a Eastencr will be provided to hole] the two ends 10, 11 in that engaged and overlapped condition. The fastener may comprise a rivet 16, but if it is desirable to reuse, or expand the diameter w the container 5, a releasable, sprung metal fastener clip 17 as shown in Figure 6 may be provided or a strap or tie which passes through aligned holes 7 at the overlap could be used, or an adjustable strap or belt which extends around the circumference of the container 5 could be used for this purpose.

It will he appreciated that in plant containers a major stress component in the wall of the container is a tensile force which is depicted in Figure 5 by arrows B. However, if the container 5 is to split at the overlap 12 the resistance to splitting as a result of the interlocking effect achieved by the interlocking of the two ends 10,11 will first need to be overcome. Due to the nesting outer and inner surface arrangement, the ends 10,11 will need to inove apart in a direction transverse to the direction of arrows A. The tendency to move apart in this manner is resisted by the fastener 16, or clip 17 and si lice there is a good interlocking effect achieved by the nesting arrangement the fastener 16 or clip 17 will not need to be particularly strong. Clearly, the greater the overlap the greater will be the interlocking effect and the more difficult it well be to split the container 5 at the overlap 12.

The diameter of the container 5 will be selected according to requirements. It is envisaged that the sheet material 4 will be formed in long lengths in a continuous C_ process, and the long lengths wAl cut to shorter lengths to form individual strips 1 for the containers 5.

It is envisaged that for initial growing (i.e.. from seedling to the end of the first growing season) the strip will be rolled in a relatively tight roll around the inner volume 14 ofthe container 5 and base 18, which may be as little as 0.5 Litres in V011.1111C, as depicted in Figures 7 and 9 of the drawings. Thereafter in the second growing season the plant would be transferred or potted up into a container 5 the size which is determined by the producer who decides the size of both pot and plant required at sale.

It is further envisaged that the container may be formed with an impermeable base in the arrangement shown in Figure 9. In the arrangement shown, the base 18 is located within the tubulr section of the container 5 and is retained in position by cooperation with the side wall. Since the side wall has a series of inwardly projecting cones or cusps 8, 9 as shown in Figure 10 a recess 26 is formed between each 2 adjacent rows. The edge of the base 18 is positioned within one such recess 26 so as to be elevated above the lower edge 25 of the container 5. The base 18 is thereby supported by the cones or cusps 8, 9 of the row which defines the lower boundary of the recess. The base 18 will be provided with a hole 19 as shown in Figure 9 to permit the passage of one leg of the clip 17.

In anothcr arrangement the base 78 is coated, prior to Insertion into the container 5 with a chemical growth retardant 27 as shown in Figure 10. The composition of the growth retardant does not form part of this invention. In this form the treated base 18, 27 is positioned within one such recess 26 so as to be elevated above the lower edge 25 ofthe container 5. The base 18, 27 is thereby supported by the cones or cusps 8, 9 of the row which defines the lower boundary of the recess. The base 18, 27 will be provided with a hole 19 as shown in Figure 9 to permit the passage of one leg of the cl 11) 17.

It is still further envisaged that the container be used to wrap up the root systems or root balls of plants dug up from the ground for the purpose of containerising or bringing theni oil above the ground as shown in Figure 11 without the use of a base 18. The strip 1 will be cut to a length that allows a significant overlap and wrapped closely to the diameter of the roots. As the root system develops within the container 5 the iaiiietei. can be expanded to enlarge the root ball. When the diameter of the container 5 i's increased in this manner the added volurne within the container will be filled with additional growing medium 24 which will add to the space in which roots within the container 5 can grow.

The size of the container can be increased as required until the ends 10, 11 are in a just overlapping configuration as depicted ill Figure 8 of tile drawings. It will be appreciated that the container is capable of being fixed at almost any diameter. The tree is depicted ill these drawings at numeral 15.

Each time the size of the container 5 is increased the inner surface 2 of the container will be gently disengaged from the root tips and soil, the strip 1 will be unravelled to all extent, and then reconnected with the peaks on the outer surface nesting within tile recesses of the inner surface of the overlapping ends. It will be appreciated that disconnection and reconnection will be simple to effect since the outer surface is the inverse shape of the inner surface and thus the two surfaces can be brought into proper engagement, in any position of diametrical adjustment, without any difficulty in manipulation or alignment.

As the two surfaces are brought together the cone shaped peaks and recesses will guide the two surfaces into proper face to face engagement. The clip 17 will then be used to hold the two surfaces in that engaged condition.

The strip 1 can be made from any suitable material although some form of thermoplastic material is considered optimum. It has also been found that a foamed polystyrene iiiatrial could be used. Foamed polystyrene has heretofore been considered too soft and pliable to forill air root pruning, plant production contaliler,s. However, with the superior connection arrangement provided by the overlapping and interlocking ends 10, 11 the resistance to shear at the overlap 12 is sufficiently great to allow for the use of this type of material.

(1 Foamed polystyrene is also considered to be a suitable material because of its good heat Insulation properties. It is envisaged that a foamed polystyrene material of between 2 and 3nim will be suitable for forming a container 5.

The aCtUal method of distorting the thermoplastics material does not form part of this invention. The sheet material shown in Figures 3 to 5 can be formed by distorting a thermoplastic sheet, whilst it is plastically deformable, with two grids of opposed prongs thereby forming the alternating peaks and recesses on opposite sides of the sheet. The peak tips on the outer surface 3 can be removed by a grinding or sawing tnl process to form the holes 7 through the sheet.

C1 A trec. 15 Is shown growing i n a container 5 in Figure 11. As will be evident, the root structure 27 oftlic tree 1-5 is well developed and substantial secondary root branching, has occurred as a result of the air pruning of the root tips 22 as they grow to close to the holes 7 in the container wall 23.

A tree 15 is shown growing ill a container 5 in Figure 12 which includes a base 18, 27. As -well as the primary and secondary root development 21 encouraged by the all, PRI11111g, priniary and secondary root development also occurs as a result of the chemically treated base 18, 27. The root Structure 21 should hold the growing rriedium 24 within the container 5.

THE CLA0v15 DEFINING THE i^.VE, NT10,1NARE AS FOLLOWS:

1. A container for growing a plant comprised of a flexible strip of material Z 1 1 1 1 1 1,' a length grealet. than its width and having an inner and an outer surface, said inner c surf - ace being Cormed in part by a lattice of root gulding recesses, at least sonie of' W W id 1 1 1 sai ecesscs being Of substantially truncated conical form having a wall which towards a hole through the strip, said outer surface being formed 'In par', bv a lailice ol'it.oti-iibei-ancl-s at the sanie relative positional arrangen-lent as the recessles.

d sitil) at W 1 1its opposite ends overlapping and the sal -1 -ran-ed in a cylinder with 1 1 - protruberances oil the outer surface of one end nesting within the recesses on the , 1 1 inner surface of the other end at the overlap, fastening means being provided to hold the strip Iii said overlapping, nested engagement.

2. A containgr accordina to claim 1 wherein said strip is fornied oa relail,elv thin slic--1 ol'l)lasties material and the formation of said recesses in said inner sitriffice produces said protrubei-ances in said outer surface.

A container accot inT to claini 1 or 2 wherein each recess leads towards a hole -d' through said strip.

4. A strip ot'[iiaterial for forming an open topped container within which a plant C_ call be orown, said strip having a length greater than its width and an 'liner surface and an miter surface, the inner surCacc being rornled in part by a lattice of root giiicilil(, i,ccc.,),scs, at least sonic oi'siicl recesses being of"siibstaiiiialiy truncated conical I'Orm havinc, a wal I which converges towards a hole through the strip, the OLIter suiTace being fornied in part by a lattice of protruberances at the same relative positional as (lie recesses, said strip being fiornied of a material which is sufficlently llexible so that strip can be rolled into a cylindrical forril with opposite ends oi'tiie strip overlapping and the protruberances on the outer surface of one end nesting within the recesses on the inner surface of the other end.

5. A sirlp according to claim 4 wherein the material is a thin thermoplastic plastics nialerial, the recesses on the inner surface forming the protruberances on the outer SLII'iaCC.

6. A strip according to claim 4 or 5 wherein each recess leads towards a hole through the strip.

7. A strip according to any one of clairns 4 to 6 wherein the material frorn.viilcli the strip Is niade Is a foanied polystyrene nialerial.

8. A base Suitable for use within the container according to claim 4, said base beim, capable of supporting a load within the container.

1). A base according to clanii 8 wherein said base includes control rneans for controlling the downward extension of root growth of a plant.

19 10. A base according to clairr, 9 wherein said control means the application of a copper based chemical growth retardant 11. A base according to clairn 8 wherein said base is adaptable for releasable connectioii to container according to claim 4.

12. A base according to clairn 10 whereiri said base is adaptable for releasable connection to container according to claim 4.

13. A method of growing a plant which is intended to be transplanted incILidiii(y the 0 Z -- steps of prov[diii,c, a strip according to claim 4, rolling said strip into a cylindrical form to form a container of relatively small diameter, retaining said container in said rolled coiidttioii with a metal clip or adjustable fastening means, inserting a base accordnig to claims 11, 12, filling said container with growing medium and planting 1 CI C.1 W a plant in said growing medium, allowing said plant to grow for a selected period of CI time.

14. A method of growing a plant which is intended to be transplanted including the steps of providing a strip according to clairn 4, rolling said strip into a cylindrical forni to form a container of relatively large diameter, retaining said container in said rolled cotiditioii with a metal clip or adjustable fastening means, filling said container with growing medium and planti.ng a plant in said growing medium, allowing said plant to grow for a selected period of time, releasing said fastening means, unrolling said strip to a degree to expand the diameter of said container, refitting the metal clip or refastemng the fastening means, and filling the expanded container with additional growirig, medium, allowing said plant to grow for a further period of time.

15. A container substantially as hereinbefore described with reference to one of the embodiments shown in the drawings.

16. A strip of material substantially as herembefore described with reference to one of the embodiments depicted in the drawings.

17. A method of growing plants substantially as hereinbefore described with reference to the drawings.

DATED: 21 May 1997