Note: Descriptions are shown in the official language in which they were submitted.
CA 02359920 2001-10-25
PLANT GROWTH UNIT
FIELD OF THE INVENTION
The present invention relates to the field of plant growth units.
BACKGROUND OF THE INVENTION
Plant growth units which attempt to conserve horizontal space and utilize
vertical
space, are known. A typical hydroponic plant growth system comprises a
nutrient
base and circulates a liquid nutrient through a cultivation portion wherein
the plant
seeds or young plants are anchored. For example, US Patent No. 5,502,923
discloses
a hydroponic plant growth system which consists of a nutrient supply module
base
which supplies liquid nutrient to a series of vertically stacked prop modules,
each
prop module containing a number of plant growth sites. As liquid nutrient is
pumped
to each prop module, water is distributed to the plants grown therein.
US Patent No. 4,986,027 discloses a plant growth apparatus comprising a
flexible
tubular element wherein slits are provided for the growth of plants. A fluid
nutrient is
supplied to the root permeable material via a pump system, the fluid nutrient
thereby
being supplied to the plants.
Similarly, US Patent Nos. 5,440,836, 5,555,676, 5,918.416 and 4,033,072 all
disclose
vertical growing columns for growing a number of plants which are supplied
water and
nutrients through the use of nutrient solution pumps in the base of the
respective
apparatuses, which supply liquid nutrient to the top of the apparatuses. The
liquid
nutrient is supplied to the plants as the liquid travels from the top of the
apparatuses to
the bases.
Further, the prior art indicates that multiple vertical plant grow columns may
utilize a
single nutrient base. For example, US Patent No. 5,363,594 discloses a
structure for a
vertically oriented plant growth unit having a plurality of vertical columns
arranged to
conserve horizontal floor space and utilize a common base for the supply of
liquid
nutrient.
CA 02359920 2001-10-25
2
One of the potential limitations of the growth units described above is that
the various
plants of the growth units may receive different types and amounts of light
from
whatever light source is utilized. The differences in light quality and
quantity may result
in a divergence in growth and quality between plants grown at various levels
and on
various sides of the vertical columns.
US Patent No. 6,178,692 discloses a lighting system for use with one or more
vertical
growing columns. The lighting system is mobile and can apparently be angled to
provide for equidistant lighting to the plants at both the top and the bottom
of the vertical
growth column. However, it would appear that equidistant lighting is to be
provided by
the lighting apparatus to a single side of each growth column. Each vertical
column
apparently has plants growing on all sides of the vertical unit and therefore
a single
lighting unit would appear only to provide equidistant lighting to those
plants which are
somewhat facing the lighting unit. To provide equidistant lighting to all
plants on the
growing columns, it would appear that two lighting units are set up on either
side of one
or more growing columns and angled to provide top to bottom. equidistant
lighting on
each side of the vertical grow columns, thereby providing equidistant lighting
to all
plants. In at least some embodiments, this system therefore appears to be
limited by the
requirement for multiple lighting units to create equidistant lighting to all
plants.
SUMMARY OF THE INVENTION
In one aspect, the present invention provides a plant growth unit including a
nutrient
supply module, one or more columns and a plurality of growth sites supported
by the
one or more columns. The nutrient supply module may be designed to contain a
liquid nutrient. The one or more columns may be radially disposed about a
central
vertical longitudinal axis to define an internal space between the one or more
columns. The internal space may be adapted to accommodate a light source. Each
column may have an upper portion, a lower portion and a longitudinal passage
through which the liquid nutrient may pass. Further, each column may be in
fluid
communication with the nutrient supply module for circulation of a liquid
nutrient
flow from the nutrient supply module to the upper portion of each of the one
or more
the columns and through the longitudinal passage to the respective lower
portion of
CA 02359920 2001-10-25
3
each of the one or more columns. The plurality of growth sites may be radially
disposed about the longitudinal axis of the growth unit, generally facing the
internal
space, and each growth site may be positioned to contact the liquid nutrient
flow.
In some embodiments, there are at least two columns and at least one growth
site on
each column. Such columns may be vertically oriented. In yet other
embodiments,
the growth unit has at least three columns, which may be circumferentially
disposed
in a generally circular pattern. In other embodiments, there is only one
column which
contains a plurality of growth sites. In such an embodiment, the single column
defines its internal space by, for example, coiling around the longitudinal
axis.
In accordance with some embodiments, two or more of the growth sites are
approximately equidistant from the longitudinal axis. In other embodiments, at
least
two growth sites are located on each of the one or more columns and at least
some of
the growth sites on each column are vertically spaced apart. In such an
embodiment,
the growth sites at generally the same vertical level may be approximately
equidistant
from the longitudinal axis. In still other embodiments, the growth unit
comprises at
least two columns and at least two growth sites are located on each column. In
such
an embodiment, the growth sites on each column may be vertically spaced apart,
and
growth sites at generally the same vertical level may be approximately
equidistant
from the longitudinal axis. .
The nutrient supply module may act as a base into which the columns are
located, and
may be shaped to facilitate balance of the system, such as disc shaped. The
columns
may be shaped to facilitate the nutrient flow from the upper portion of each
of the
columns to the lower portion of each of the columns, such as tubular columns.
The plant growth unit may further include one or more fluid connectors, such
as
tubes, which connect the nutrient supply module with the upper portion of each
of the
one or more columns. The fluid connectors may be designed to facilitate the
liquid
nutrient flow from the nutrient supply module to the tops of each of the one
or more
columns. The plant growth unit may also include a pump, or pumps, facilitating
the
liquid nutrient flow.
CA 02359920 2001-10-25
4
Where each column supports a plurality of growth sites, the growth sites may
be
longitudinally aligned. In some embodiments, the growth sites may protrude
upwardly from the columns. The plant growth unit may also include a plurality
of
baskets which are designed to hold plants and designed to attach to the growth
sites.
The plants may be anchored to the growth unit by being placed inside the
baskets,
which are then attached to the growth sites.
Other embodiments of the present invention provide methods for growing plants
in a
growth unit. A nutrient supply module may be adapted for holding a liquid
nutrient.
One or more columns may be radially disposed about a central vertical
longitudinal
axis of the growth unit, thereby defining an internal space between the one or
more
columns. The columns may be disposed in fluid communication with the nutrient
supply module and the internal space may be adapted to accommodate a light
source.
Each column may be designed with an upper portion, a lower portion and a
longitudinal passage through which the liquid nutrient may pass. The nutrient
supply
module may be connected to the upper portion of the columns. A plurality of
growth
sites may be provided supported by the columns. The growth sites may be
disposed
radially about the longitudinal axis and generally facing the internal space.
A
plurality of plants may be then be located in the growth sites and the liquid
nutrient
may be added to the supply module. The liquid nutrient rnay then be circulated
from
the nutrient supply module to the upper portion of each of the one or more
columns,
through the longitudinal passage to the respective lower portion of each of
the one or
more columns. During its circulation, the liquid nutrient may be brought into
contact
with the plants.
In such a method, the introduction of a plurality of growth sites may further
include
locating at least two of growth sites equidistant from the longitudinal axis.
During the
introduction of a plurality of growth sites, at least two growth sites may be
introduced
on each of the one or more columns, at least some of such growth sites being
vertically spaced apart on the columns. In such a method, the growth sites
being at
generally the same vertical level may be located approximately equidistant
from the
longitudinal axis. In another such method, at least two columns may be
disposed and
at least two growth sites may be introduced on each of the columns, such
growth sites
being vertically spaced apart on each column. In such a method, the growth
sites
CA 02359920 2001-10-25
which are at generally the same vertical level may be located approximately
equidistant from the longitudinal axis.
While specific embodiments of the invention have been described and
illustrated,
5 such embodiments should be considered illustrative of the invention only,
and not as
limiting the invention to particular embodiments.
BRIEF DESCRIPTION OF THE DRAWINGS
In drawings which illustrate the embodiments of the invention,
Figure 1 is an isometric view of a plant growth unit according to an
embodiment
of the invention
Figure 2 is a longitudinal cross-sectional view of the plant growth unit of
Fig. 1
Figure 3 is an elevational side view of a plant growth unit, in an embodiment
including two columns
Figure 4 is a top view of the plant growth unit of Fig. 1
Figure 5 is a bottom view of the plant growth unit of Fig. 1
Figure 6 is a longitudinal broken away cross-sectional of a portion of the
column of the plant growth unit of Fig. ll
Figure 7 is an elevational view of a plant growth unit, in an embodiment which
includes a single column
DETAILED DESCRIPTION
Referring collectively to Figures l, 2 and 4 through 6, a plant growth unit
according
to one embodiment is shown. The plant growth unit includes a nutrient supply
module 10, a plurality of columns 20, and a plurality of growth sites 30
supported by
the columns 20.
The nutrient supply module 10 is designed to contain a liquid nutrient 12. In
the
embodiment shown, the nutrient supply module 10 acts as a base for the plant
growth
unit. The nutrient supply module 10 thereby stabilizes the plant growth unit
and the
columns 20 contained therein. However, the nutrient supply module need not act
as a
CA 02359920 2001-10-25
6
base for the growth unit, which may be anchored or stabilized by alternative
structures or supports.
The nutrient supply module 10 as shown in Figure s 1 through 5 is disc shaped.
However, the nutrient supply module may take on various shapes adapted to
enable it
to act as a nutrient supply module in fluid communication with the columns 20.
Where the nutrient supply module 10 is intended to act as a base for the
growth unit, it
may be designed to maintain balance and support of the growth unit when placed
on
its intended surface.
The nutrient supply module 10 may have a hole in the upper portion of the
nutrient
supply module 10 located approximately at the longitudinal axis 40, such a
hole being
adapted to hold a mesh basket for collecting medium and dead foliage to later
be
discarded, a allowing excess liquid nutrient 12 to pass into the nutrient
supply module
10. It is not necessary that the nutrient supply module 10 have such a hole.
The outer
portion of the upper surface of the nutrient supply module 10 may also slope
downwardly towards the longitudinal axis 40, allowing excess liquid nutrient
12
dripping from the columns 20 to drain towards the longitudinal axis 40 and the
hole
which may be present in the nutrient supply module 10. The upper surface of
the
nutrient supply module 10 may also be level, or may slope in other directions.
The nutrient supply module 10 may be made of plastic, such as food grade
polyethylene or food grade polycarbonate. The nutrient supply module 10 may be
manufactured by, for example, placing food grade polyethylene powder in an
aluminum mold, which is then heated and rotated on two separate axes. The food
grade polyethylene in the mold melts as the mold is heated and the centripetal
force of
the rotation forces the melted plastic to the walls of the aluminum mold where
it cools
as the mold is removed from the heat. The nutrient supply module 10 is then
removed
from the mold. In alternative embodiments, the nutrient supply module 10 may
be
manufactured from a variety of other materials capable of containing the
liquid
nutrient 12 and allowing for fluid communication with the columns 20.
In the illustrated embodiment of Figures 1, 2, and 4 through ~6, the columns
20 are
radially disposed about a central vertical longitudinal axis 40 and define an
internal
CA 02359920 2001-10-25
7
space 42 between the columns 20. In the embodiments illustrated in Figures 1,
2
and 4 through 6, four columns 20 are disposed approximately equidistant from
the
longitudinal axis 40 and approximately equidistant from each other, as shown
in
Figure 4. Any number of columns 20 may be arranged about the longitudinal axis
40.
For example, as shown in Figure 3, two columns 20 rnay be radially disposed
about
the longitudinal axis opposite each other. The columns 20 may be equidistant
from
the longitudinal axis 40 and equidistant from each other. Where there are at
least
three columns, the columns may be circumferentially disposed in a generally
circular
pattern. In alternative embodiments, the columns 20 need not be equidistant
from the
longitudinal axis 40 or each other, while the columns 20 remain radially
disposed
about the longitudinal axis 40 and define an internal space 42.
The columns 20 are generally vertically oriented and generally straight in the
embodiments shown in Figures 1 through 6. In alternative embodiments, it is
not
necessary that the columns be vertically oriented and/or straight. The columns
may
be angled in any direction, and at any degree. For example, the columns may be
tilted
towards or away from the longitudinal axis 40. The columns may also be of
vaxious
appropriate curvatures or shapes. Appropriate curvatures and shapes of the
columns
may be selected so as to maintain the other functional objectives of the
various
embodiments of the invention.
The internal space 42 may be adapted to accommodate a light source. The light
source may be, for example, a tubular light source which can be supported, for
example by hanging, vertically between the columns 20 in the internal space
42. In
some embodiments, for generally equidistant lighting and advantageous
conditions for
all plants growing in the growth unit, the tubular light source may be
supported
approximately along the longitudinal axis. Alternatively, as shown in the
alternative
embodiment of Figure 3, the light source could be a series of bulbs 44
supported
vertically between the columns 20 in the internal space 42, in some
embodiments the
series of bulbs 44 being aligned approximately along the longitudinal axis for
generally equidistant lighting. A series of bulbs 44 may, for example, be
vertically
supported hung by a chain 46, or other support, from, for example, a support
beam 48.
The light source could also, for example, be a bulb hung in the internal
space, or
supported in the internal space by the base along the longitudinal axis.
Appropriate
CA 02359920 2001-10-25
bulbs for use as a light source include 400watt Metal Halide, 400watt High
Pressure Sodium, 250watt Metal Halide, 250watt High Pressure Sodium and
430watt
Son Agro. Larger bulbs, such as 600watt High Pressure Sodium, 1000watt High
Pressure Sodium or 1000watt Metal Halide, may also be used; however, when
larger
bulbs such as these are used as a light source for the plant growth unit, they
may have
to be continuously moved up and down the longitudinal axis when lit.
Each column 20 may have an upper portion 22, a lower portion 24 and a
longitudinal
passage 26 through which the liquid nutrient 12 may pass. The columns 20 may
be
tubular, thereby defining the longitudinal passage 26. The columns 20 may be
made
of plastic or another suitable material, such as clay, metal or wood. The
columns 20
may, for example, be manufactured by way of known injection mold techniques,
or
extruding plastic techniques. Alternatively, the columns 20 could be
manufactured
from pre-existing ABS or PVC elbows, Tee's and straight lengths, which can be
glued
together. Metal elbows, Tee's and straight pipes could be welded together to
form the
columns 20. The columns 20 could alternatively be carved from wood, or other
carvable material, or could be formed by gluing or nailing wooden planks
together to
form square columns. A column may also be formed from clay by shaping clay
pieces and then mounting the clay pieces into a column.
The columns 20, in the embodiments shown, rest on the bottom of the nutrient
supply
module 10 and have a hole in the column such that the liquid nutrient flow 14
may
pass out of the lower potion 24 of the columns 20. In alternative embodiments,
the
columns 20 may be supported above the bottom of the nutrient supply module and
the
2~ liquid nutrient flow 14 may pass out of the bottom of the columns 20.
In some embodiments, the longitudinal passage 26 may be hollow or may contain
a
permeable material, such as a planting medium, through which the liquid
nutrient 12
is able to pass. Suitable planting medium includes, bur. is not limited to,
HydrotonTM
(or other small round, kiln heated clay types), Sunshine MixTM (or other peat
perlite
soil like mixes), perlite, vermiculite, rockwool, washed rock, sand, foam or
animal
castings. The permeable material is also not limited to planting medium. It
may be
possible to use a wide range of material which allows for the passage of the
liquid
CA 02359920 2001-10-25
9
nutrient 12 through the longitudinal passage 26, while still allowing the
growth unit to meet the other functional objectives of various embodiments of
the
invention.
Each column 20 may be in fluid communication with the nutrient supply module
12
for circulation of a liquid nutrient flow 14. In the embodiments shown in
Figures 1
through 6, a plurality of pumps 16 circulate the liquid nutrient 12 from the
nutrient
supply module 10 through a plurality of tubes 18 to tile upper portion 22 of
each of
the columns 20 and through the longitudinal passage 26 to the respective lower
portion 24 of each of the columns 20. In alternative embodiments, a single
pump may
facilitate the liquid nutrient flow 14. In some embodiments, once the liquid
nutrient is
pumped to the end of the tubes 18 at the upper portion 22 of each of the
columns 20,
the liquid nutrient is allowed to cascade down the longitudinal passage and
back into
the nutrient supply module 10 via gravitational pull. The pumps 16 may be, for
example, Little GiantTM sump pump 1200gph, or other such pumps manufactured by
MagdriveTM and RioTM. The tubes 18 may be, for example, %2 inch commercial
garden hose, %2 inch rubber garden hose, %2 inch ABS hose or other size hoses
of the
same type. The system connecting the tubes 18 to the columns 20 and the pumps)
16
may incorporate ABS elbows, ABS stop plugs, hose clamps, rubber washers, 1/2
inch
ABS tees, 1/2 inch shut off values and female to male hose adaptors, arranged
to
facilitate the liquid nutrient flow 14. Other types of fluid connectors are
also
contemplated by the present invention.
Alternative means for establishing the liquid nutrient flow 14 are also
contemplated.
For example, a pump may be located near the upper portion 22 of the columns 20
to
pull the liquid nutrient 12 from the nutrient supply module 10. The tubes 18
do not
have to be inside the columns 20, but may connect the nutrient supply module
10 to
the upper portion 22 of each of the columns 20 on the outside of the columns
20. The
present invention contemplates such other means for establishing the liquid
nutrient
flow.
In the embodiments illustrated, a plurality of growth sites 30 are located on
each
column 20, such growth sites 30 being radially disposed about the longitudinal
axis 40
and generally equidistant from the longitudinal axis 40. As illustrated, the
growth
CA 02359920 2001-10-25
sites 30 generally face towards the internal space 42. This provides
generally equidistant lighting in the embodiment shown to all plants in the
growth
unit when a tubular light source is vertically supported along the
longitudinal axis 40.
5 There may be one or more growth sites 30 on each column 20. Where there is
more
than one growth site 30 on each column 20, the growth sites 30 may be
vertically
spaced apart on the columns 20.
The growth sites 30 may be equidistant from the longitudinal axis 40 for
equidistant
10 lighting, even where the columns 20 themselves are not equidistant from the
longitudinal axis 40. However, in some embodiments the present invention also
contemplates a growth unit where the growth sites are not equidistant from the
longitudinal axis 40.
Where at least some of the growth sites 30 are vertically spaced apart on the
columns
20, those growth sites 30 which are at generally the same vertical level may
be
equidistant from the longitudinal axis. This may provide advantageous lighting
conditions to all the plants where, for example, a single bulb, located along
the
longitudinal axis, is used as a lighting source. In such a growth unit, the
growth sites
vertically further away from the bulb may be situated closer to the
longitudinal axis
than those growth sites vertically closer to the bulb, in order that all
plants receive
equidistant lighting for advantageous conditions. Those growth sites at the
same
vertical level may therefore be equidistant from the longitudinal axis, when
even
where not all growth sites in the growth unit are equidistant from the
longitudinal
axis. A variation in the distance of the growth sites from the longitudinal
axis may be
accomplished by tilting the columns or designing the columns to vary in
distance
from the longitudinal axis. Alternatively, the growth sites may protrude from
the
columns at different lengths, varying the distance of the growth sites at
different
vertical levls to the longitudinal axis.
The growth sites 30 in the embodiments illustrated in Figures 1 through 6
protrude
upwardly from the columns 20 in order to facilitate anchoring plants at the
growth
sites 30. The growth sites 30 in the embodiments illustrated angle upwardly at
approximately a forty-five degree angle. The growth sites 30 may protrude from
the
CA 02359920 2001-10-25
11
columns 20 at alternative angles, however l:he angle will preferably be
chosen as one appropriate to maintain plants in growth sites. The present
invention
also contemplates a growth unit where the growth sites 30 do not protrude from
the
columns 20.
In the embodiments shown in Figures 1 through 6, the growth sites 30 form a
unitary
part of the columns 20, the entire structure being formed from plastic or
another
suitable material. The invention also contemplates a growth unit where the
growth
sites 30 are not formed as a part of the columns 20, but are later attached to
the
growth unit as separate components.
The growth sites 30 shown in the illustrations have circular openings 32 into
which
plants may be anchored and grown. The present invention is not limited to
growth
sites which have circular openings for receiving the plants. The growth sites
may take
various forms which would allow for a plant to be grown. For example, the
various
shapes and sizes of planting pots as normally found in the field of gardening
may be
used as growth sites, the size being limited of course by the size of the
growth unit.
Accordingly, a wide variety of types of growth sites that could be used in
growth units
are contemplated by this invention.
In the embodiments shown in Figures 1 through 6, the growth unit includes
baskets 34
which fit into the circular openings 32 of the growth sites 30. As shown in
Figure 6,
the baskets 34 may be designed to hold plants 36. The baskets 34 may be made
of
plastic or another suitable material. In the embodiment shown, the baskets 34
are
open weave baskets. The plants 36 sit in the baskets 34 and the plant roots 38
protrude through the bottom of the baskets 34. The present invention also
contemplates other means for retaining the plants in the growth sites. For
example,
the columns 20 may contain a planting medium in the longitudinal passage 26
into
which the plants may be anchored and grown.
Each growth site 30 may be positioned to contact the liquid nutrient flow 14.
The
plants 36 may be located in the baskets 34, which are placed in the growth
sites 30,
and the plant roots 38 protrude from the base of the baskets 34, as
illustrated in Figure
6. The plant roots 38 are therefore located within the longitudinal passage 26
of the
CA 02359920 2001-10-25
12
column 20. As the liquid nutrient flow 14 is established through the
longitudinal
passage 26, the liquid nutrient flow 14 will come into contact with the plant
roots 38.
There are other means for positioning the various types of growth sites such
that the
plant roots will come into contact with the liquid nutrient flow as it passes
through the
longitudinal passage of the columns. For example, where the longitudinal
passage
contains planting medium into which the plants are anchored at the growth
sites, the
roots of the plants will come into contact with the liquid nutrient flow as it
travels
through the planting medium.
Various types of liquid nutrient 12 may be used. The liquid nutrient may
contain
essential elements needed for plant growth, such as Nitrogen, Phosphorus,
Calcium,
Magnesium, Sulphur, Iron, Potassium, Boron, Manganese, Zinc, Copper, and
Molybdenum. For example, GGold Nutrient LineTM or General Hydroponics Flora
Lines contain these essential elements needed for plant growth and therefore
may be
used as the liquid nutirent. The quality, quantity and type of liquid nutrient
used will
vary depending on many factors, such as the type and age of the plants being
grown.
The liquid nutrient should be chosen with a view to establishing advantageous
growth
conditions.
Referring to Figure 7, a plant growth unit according to an alternative
embodiment of
the invention is shown. The plant growth unit includes a nutrient supply
module 50, a
single column 60 and a plurality of growth sites 70 supported by the column
60. As
described above, the nutrient supply module 50 is designed to contain a liquid
nutrient
52 and, as in the embodiment shown, may act as a base for the growth unit. The
nutrient supply module 50 may take on various shapes and various modes of
manufacture, as outlined above.
As shown in Figure 7, the single column 60 is disposed radially about a
central
vertical longitudinal axis 80 and defines an internal space 82. This may be
accomplished by wrapping the column 60 around the longitudinal axis. In the
embodiment illustrated, the column 60 forms a uniform helical structure. The
column
60 may, at all points, be generally equidistant from the longitudinal axis 80.
However, the present invention contemplates many various forms that the column
60
CA 02359920 2001-10-25
13
may take in order to dispose itself radially about the central longitudinal
axis 80 and define an internal space 82. The column 60 need not vertically
rise in a
uniform manner and all portions of the column 60 need not be equidistant from
the
longitudinal axis 80.
The internal space 82 in Figure 7, as with the previously described
embodiments, may
be adapted to accommodate a light source. A variety of light sources may be
used, as
described above.
The column 60 may have an upper portion 62, a lower portion 64 and a
longitudinal
passage 66 through which the liquid nutrient may pass. As described above, the
column 60 may be made of a variety of materials and constructed in a variety
of ways.
Further, as also described above, the longitudinal passage 66 may be empty or
contain
a permeable material through which the liquid nutrient 52 may pass.
The column 60 may be in fluid communication with the nutrient supply module 50
for
circulation of a liquid nutrient flow 54. In the embodiment shown in Figure 7,
a pump
56 circulates the liquid nutrient from the nutrient supply module 50 through a
tube 58
to the upper portion 62 of the column 60 and through the longitudinal passage
66 to
the lower portion 64 of the column 60. As described above, various pumps 56
and
tubes 58 are contemplated, as are other methods of establishing the liquid
nutrient
flow 54.
In an embodiment of the invention including a single column 60, a plurality of
growth
sites 70 may be located on the column 60. The growth sites 70 are radially
disposed
about the longitudinal axis 80 and the growth sites 70 generally face towards
the
internal space 82. In the embodiment shown, the growth sites 70 are located
equidistant from the longitudinal axis 80, resulting in equidistant lighting
to all plants
in the growth unit when a vertical light source is supported along the
longitudinal axis
80. Though the growth sites 70 may be equidistant from the longitudinal axis
80, as
described above, the growth sites need not be equidistant from the
longitudinal axis.
In alternative embodiments, only those growth sites at generally the same
vertical
level may be equidistant from the longitudinal axis.
CA 02359920 2001-10-25
14
As also discussed above, in embodiemtns such as illustrated in Fig. 7, the
growth
sites 70 may or may not protrude from the column 60, and may do so at various
distances and angles. The growth sites 70 may be of various shapes and sizes,
and the
growth unit may use various means for anchoring the plants in the growth sites
70.
The growth sites 70 may be positioned to contact the liquid nutrient flow 54
in the
various ways described above and there are various options for the liquid
nutrient to
be used.
The present invention also contemplates a method for growing plants where a
plant
growth unit as described above is provided, plants are planted into the growth
sites
and a liquid nutrient flow is established.
While specific embodiments of the invention have been described and
illustrated,
such embodiments should be considered illustrative o:E the invention only and
not as
limiting the invention as construed in accordance with the accompanying
claims.
