Abstract:
A plant pot comprising a base and at least one side wall, the base and the side wall together defining an at least one chamber of fixed dimensions for receiving an at least one plant and a growing medium, wherein a plurality of apertures are formed in the at least one side wall, each aperture permitting passage of a root of the at least one plant from the chamber through the side wall to an exterior of the plant pot. Plants, typically trees, are normally grown in such pots in the ground and their recovery for onward sale is facilitated by the use of such pots.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is a claims priority under 35 U.S.C. §119 to United Kingdom Patent Application Serial No. 0718757.8 filed on Sep. 26, 2007, entitled “Plant Pot,” the disclosure of which is hereby incorporated by reference. 
       INTRODUCTION TO THE INVENTION 
       [0002]    The present invention relates to a plant pot. In particular, but not exclusively, the present invention relates to a plant pot of a type suitable for use in the field growing of plants. 
         [0003]    In the horticultural industry, it is common practice to ‘field-grow’ plants directly in the ground for a number of years and, when the plant has reached a sufficient or desired level of maturity, to transfer the plant into a pot for onward transport to a customer, and/or for display and sale in a retail outlet such as a garden centre. This growing method is particularly applicable to trees, which are relatively slow growing. 
         [0004]    A significant problem with this growing method is that the plant roots, being unconstrained when field-grown, develop an extensive root network which is frequently damaged when the plant is dug-up for transfer to a pot. As a result, a significant number of field-grown plants die within a few days or weeks of being dug-up and transferred to a pot. The suitability of this growing method is also dependent to a great extent upon the sensitivity of the plant in question to such treatment, some plants being more sturdy and less likely to suffer permanent harm than others. 
         [0005]    It is therefore amongst the objects of embodiments of the present invention to obviate or mitigate at least one of the foregoing disadvantages. 
         [0006]    According to a first aspect of the present invention, there is provided a plant pot comprising a base and at least one side wall, the base and the side wall together defining an at least one chamber of fixed dimensions for receiving an at least one plant and a growing medium, wherein a plurality of apertures are formed in the at least one side wall, each aperture permitting passage of a root of the at least one plant from the chamber through the side wall to an exterior of the plant pot. 
         [0007]    Typically an at least one plant and growing medium is supplied into the pot chamber, and the filled/partially filled pot is then located in a hole in the ground in a suitable location. Root growth through the apertures occurs, giving the plant access to nutrients and/or water. When the time comes to dig-up the plant, this is achieved simply by digging around the pot (if necessary) and lifting the pot up out of the ground. The roots which established by growing out through the apertures in the pot shear off and remain in the ground (although it is envisaged that a quantity of roots may have sufficient rigidity to resist shearing and thus may remain in place). In this fashion, a main root ball or clump of the plant, grown and held within the chamber, remains intact, reducing injury to the plant when compared to conventional field-growing techniques. 
         [0008]    It will therefore be understood that providing a plant pot having an at least one side wall including such apertures permits the plant to grow and develop a root system extending from the chamber into the ground around the pot, so that the plant may access water and/or nutrients, but restricts growth of said roots such that shearing of the roots when the pot is removed from the ground does not result in a fatal damage to the plant. Additionally, a main root ball or clump formed within the pot chamber remains substantially intact during this process. 
         [0009]    The plant pot may be adapted, in use, to be at least partly buried and thus to be at least partly located below ground level. The plant pot may be adapted to be located, in use, with the apertures below ground level. 
         [0010]    The plant pot may be of a sufficient rigidity such that the pot defines the fixed dimension chamber in the absence of an at least one plant and growing medium, and may also be of sufficient rigidity such that the pot substantially retains its shape (and thus the dimensions of the chamber) following location of an at least one plant and growing medium in the chamber. This may facilitate location of the plant in the pot, and charging of the growing medium into the pot. 
         [0011]    The apertures may be circular in cross-section, and may have a diameter in a range of 2 mm to 5 mm, inclusive. In a preferred embodiment the apertures may have a diameter in the range of 2.5 mm to 3.5 mm. In a more preferred embodiment, the apertures may have a diameter of about 3 mm. Providing the apertures at a diameter of about 3 mm has been found to offer particular advantages in terms of: permitting growth of a root of sufficient diameter to enable recovery of adequate levels of nutrients and/or water from the soil surrounding the pot; restricting growth of the root to an extent which would be likely to result in the root deforming and/or breaching a wall of the aperture and thus damaging the pot; restricting growth of the root to an extent that damage to said root does not result in a fatal injury to the plant when the pot is lifted from the ground; and in restricting growth of the root to an extent that a main root growth activity occurs within the pot chamber and thus that the plant develops a strong root ball or clump within the chamber. 
         [0012]    Typically, in providing apertures within the above range and in particular at a 3 mm diameter, the at least one plant develops a main root which extends through the growing medium towards an internal opening of an aperture. Further free growth of the root through the aperture is restricted by selection of the aperture diameter to be in the above range. A callous then forms on the root at a location adjacent the aperture internal opening, causing an extended root portion to be thrown from the callous through the aperture, the extended portion being of sufficiently small diameter to pass through the aperture and into soil surrounding the plant pot. 
         [0013]    The apertures may extend around a perimeter or circumference of the plant pot, and/or may extend in a direction along a length of the side wall of the plant pot. At least some of the apertures may be arranged in arrays or patterns of apertures, and the shapes of the arrays or patterns may be selected to promote root growth. 
         [0014]    The apertures may extend around the side wall of the plant pot. The apertures may extend upwards from the base along a vertical length of the side wall of the plant pot. The apertures may be evenly spaced in an array. 
         [0015]    The volume may be in the range of 5 and 30 liters for example the plant pot may have an internal volume of 5, 7.5, 10, 15, 20, 25 or 30 liters. 
         [0016]    The plant pot may have more than 100 apertures. The plant pot may have less than 1000 apertures, preferably less than 500 apertures. 
         [0017]    In one embodiment a 7.5 liter plant pot has 164 apertures. In another embodiment a 10 liter plant pot has 180 apertures. 
         [0018]    The plant pot may be circular in cross-section, or may be polygonal in cross-section and thus the plant pot may comprise a plurality of side walls. For example, the plant pot may be square in cross-section and thus may comprise four side walls, each side wall comprising a plurality of apertures. 
         [0019]    A plurality of apertures may also be formed in the base of the plant pot, and the apertures in the base may be of similar dimensions and/or arranged in similar arrays or patterns as the apertures in the at least one side wall. The apertures in the base of the plant pot may be between 2 and 5 mm in diameter. 
         [0020]    The apertures may be drilled or otherwise formed in the side wall of the plant pot. Alternatively, the plant pot may be manufactured including the apertures. For example, the plant pot may be of a plastics material and the pot may be molded to include the apertures. 
         [0021]    In alternative embodiments, apertures of alternative shapes and/or diameters or dimensions to that defined above may be provided. 
         [0022]    It will be understood that references herein to plants should be taken to include, inter alia, trees, herbs, bushes/shrubs, grasses, perennial, biennial and annual plants and the like. In addition, it will be understood that references herein to a growing medium for plants should be taken to include naturally occurring and manufactured or synthesized mediums including, inter alia, soils, composted material, fertilizers and combinations thereof. 
         [0023]    According to a second aspect of the present invention, there is provided a method of growing a plant comprising the steps of: (a) providing a plant pot comprising a base and at least one side wall, the base and the side wall together defining an at least one chamber of fixed dimensions; (b) locating a plant and a growing medium in the chamber of the plant pot; (c) locating the plant pot containing the tree and the growing medium in a hole in the ground; (d) permitting root growth through a plurality of apertures formed in the side wall of the plant pot and into the ground surrounding the plant pot; and (e) when the plant has reached a desired level of maturity, digging-up the plant pot including the plant and the growing medium. 
         [0024]    When the plant pot is dug-up, a majority or all of the roots which have grown through the apertures may be sheared and may remain in the ground. 
         [0025]    The level of maturity may be between 2 and 6 years, such as 4 years. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0026]      FIG. 1  is a perspective view of a plant pot in accordance with a preferred embodiment of the present invention; 
           [0027]      FIG. 2  is a partial cross-sectional perspective view of the plant pot of  FIG. 1  shown in use in the field-growing of a plant; and 
           [0028]      FIG. 3  is a partial cross-sectional plan view of the plant pot of  FIG. 1  showing a root system of the plant of  FIG. 2  in more detail. 
       
    
    
     DETAILED DESCRIPTION 
       [0029]    The exemplary embodiments of the present invention are described and illustrated below to encompass a plant pot. In particular, but not exclusively, the present invention relates to a plant pot of a type suitable for use in the field growing of plants. Of course, it will be apparent to those of ordinary skill in the art that the preferred embodiments discussed below are exemplary in nature and may be reconfigured without departing from the scope and spirit of the present invention. However, for clarity and precision, the exemplary embodiments as discussed below may include optional steps, methods, and features that one of ordinary skill should recognize as not being a requisite to fall within the scope of the present invention. 
         [0030]    Turning firstly to  FIG. 1 , there is shown a perspective view of a plant pot, (or a container for a plant) in accordance with a preferred embodiment of the present invention, the plant pot indicated generally by reference numeral  10 . 
         [0031]    The plant pot  10  is circular in cross-section, and generally comprises a base  12  and a side wall  14 . A plurality of apertures  16  are formed in the side wall  14  of the pot  10 . In the illustrated embodiment, the plant pot  10  is of a plastics material of a type typically used in the manufacture of conventional plant pots, and the apertures  16  are formed in the side wall  14  using a suitable drill. However, it will be understood that the plant pot may be molded including the apertures. 
         [0032]    In the preferred embodiment shown, the apertures  16  are about 3 mm in diameter, although other diameters may be selected, typically within the range of 2 mm to 5 mm, inclusive. As will be described below, however, forming the apertures with a diameter of about 3 mm offers particular advantages in use of the pot  10 . The apertures  16  extend around a circumference of the pot  10  side wall  14 , as well as along the vertical length of the side wall  14 . 
         [0033]    The plant pot base  12  and side wall  14  together define a chamber  18  of fixed dimensions for receiving a plant and a growing medium for the plant, which will be described below. Providing the plant pot defining such a fixed dimension chamber  18  facilitates location of a plant and charging of a growing medium into the pot  10 . 
         [0034]    The plant pot  10  has a particular utility in the field-growing of plants, especially trees, which are relatively slow growing, and is shown in a field-growing situation in the partial cross-sectional perspective view of  FIG. 2 . A plant in the form of a tree  20  has been located in the chamber  18  of the pot  10 , together with a suitable growing medium  22  (typically a balanced mixture of soil/compost/fertilizer). The filled pot  10  is then transported to a location in which the tree  20  is to be field-grown, although it will be understood that the pot  10  may be filled on-site. A hole  24  is dug in ground  26 , and the filled pot  10  is located in the hole, and the space around the pot  10  back-filled. 
         [0035]    In  FIG. 2 , the soil in the area of ground  26  below a surface  28  level is shown in cross-section, to ease illustration of a root system  30  of the tree  20  which has developed over a period of time. Reference is also made to  FIG. 3 , which is a partial cross-sectional plan view of the pot  10  showing the root system  30  in more detail. 
         [0036]    Over time, the tree  20  develops a main root ball or clump (not shown) within the chamber  18  of the pot  10 . The tree  20 , in seeking water and nutrients, also throws roots towards the apertures  16  in the pot side wall  14 . By forming the apertures  16  to be of about 3 mm diameter, growth of the roots through the apertures  16  is restricted. This is illustrated in  FIG. 3 , where a main root  32 , thrown from the root ball or clump, has encountered an aperture  16 . Initially, the root portion  32  attempts to force its way through the aperture  16 , resulting in the formation of a callous  34 . After a further time period in which the root portion  32  has found it impossible to grow and extend through the aperture  16 , an extended root portion  36  shoots off from the callous  34  and passes through the aperture  16 . This extended portion  36  passes into the ground  26  surrounding the pot  10 , and facilitates recovery of water and nutrients from the ground  26 , stimulating growth of the tree  20 . 
         [0037]    Careful selection of the aperture  16  diameter to be in the range of 2 mm to 5 mm and in particular about 3 mm, ensures that the growth of the extended root portion  36  is restricted. In particular, the diameter of the root portion  36  is restricted such that the root portion does not deform the aperture  16 . Additionally, in restricting root growth in this fashion, the root potion  36  is prevented from growing to a sufficiently large diameter that would both cause difficulties in subsequent transplantation of the tree  20 , and which would cause potentially fatal injury to the tree  20  should the root portion  36  be damaged during transplantation. Indeed, selection of the aperture diameter as described above produces an extended root portion  36  which is specifically intended to shear off when the tree  20  is to be transplanted, this being achieved without fatal injury to the tree  20 . 
         [0038]    It will be appreciated that an extensive network of such extended root portions  36  forms over time, as shown in  FIG. 2 . When the tree  20  has reached a desired level of maturity, the entire filled plant pot  10  is dug-up from the ground  26 . During this process, most or all of the extended root portions  36  shear off and remain in the ground. However, as described above, this is not fatal to the tree  20 , and the main root ball or clump within the chamber  18  remains largely or completely intact. The pot  10  is then transported to a retail outlet such as a garden centre, and is maintained in the pot  10  for storage and display purposes. It will be appreciated, however, that the tree  20  in the filled pot  10  is suitable for direct sale to a customer following removal from the ground  26 . 
         [0039]    Various modifications may be made to the foregoing without departing from the spirit and scope of the present invention. 
         [0040]    For example, the plant pot may define a plurality of chambers, each chamber being for receiving a respective plant. If desired, a plurality of plants may be located in the or each chamber. 
         [0041]    The apertures may be arranged in alternative arrays or patterns, and the arrays or patterns may be selected to promote root growth. 
         [0042]    The plant pot may be of alternative shape, and may be polygonal (for example, square) in cross-section. 
         [0043]    Apertures may be provided in the base and may be sized similarly to the apertures in the side wall. 
         [0044]    Following from the above description and invention summaries, it should be apparent to those of ordinary skill in the art that, while the methods and apparatuses herein described constitute exemplary embodiments of the present invention, the invention contained herein is not limited to this precise embodiment and that changes may be made to such embodiments without departing from the scope of the invention as defined by the claims. Additionally, it is to be understood that the invention is defined by the claims and it is not intended that any limitations or elements describing the exemplary embodiments set forth herein are to be incorporated into the interpretation of any claim element unless such limitation or element is explicitly stated. Likewise, it is to be understood that it is not necessary to meet any or all of the identified advantages or objects of the invention disclosed herein in order to fall within the scope of any claims, since the invention is defined by the claims and since inherent and/or unforeseen advantages of the present invention may exist even though they may not have been explicitly discussed herein.