HYDROPONIC GROWING MEDIUM
A hydroponic growing medium ( 39 ) comprising a three-dimensional self-supporting substrate ( 39 ) having a dry bulk density of about 1.8 lb/ft 3 (28.83 kg/m 3 ) to 10 lb/ft 3 (160.185 kg/m 3 ) and including at least about 2 to 10 weight % of a man-made fiber portion ( 24 ) and at least about 90 to 98 weight % of a natural fiber portion ( 22 ) having wood fiber, based on the total weight of the hydroponic growing medium ( 39 ).
1 . A hydroponic growing medium comprising:
a three-dimensional self-supporting substrate having a dry bulk density of about 1.8 lb/ft 3 (28.83 kg/m 3 ) to 10 lb/ft 3 (160.185 kg/m 3 ) and including at least about 2 to 10 weight % of a man-made fiber portion and at least about 90 to 98 weight % of a natural fiber portion having wood fiber, based on the total weight of the hydroponic growing medium.
2 . The hydroponic growing medium of claim 1 , wherein the hydroponic growing medium has total porosity of about 90 to 99 volume %.
3 . The hydroponic growing medium of claim 1 , wherein the hydroponic growing medium has about 30 to 60 percent of air space.
4 . The hydroponic growing medium according to claim 1 , wherein the hydroponic growing medium has volumetric water content at pF 1 of about 25 to 70%.
5 . The hydroponic growing medium according to claim 1 , wherein the hydroponic growing medium has volumetric water oxygen at pF 1 of about 50 to 80%.
6 . The hydroponic growing medium according to claim 1 , wherein the total water holding capacity of the hydroponic growing medium is about 40 to 80 wt. %.
7 . The hydroponic growing medium according to claim 1 , wherein the man-made fiber portion includes at least one kind of bicomponent fiber.
8 . The hydroponic growing medium according to claim 7 , wherein the bicomponent fiber includes an outer shell having a first material and a core having a second material, the first material having a lower melting temperature than the second material.
9 . The hydroponic growing medium according to claim 1 , wherein the three-dimensional self-supporting substrate forms a slab.
10 . The hydroponic growing medium according to claim 9 , wherein the slab includes at least one recess.
11 . The hydroponic growing medium according to claim 10 , wherein the at least one recess has about 5-20 cm in diameter and a depth of about 5-10 cm.
12 . The hydroponic growing medium according to claim 1 , wherein the slab has a dry bulk density of about 1.8 lb/ft 3 (28.83 kg/m 3 ) to about 5 lb/ft 3 (80.09 kg/m 3 ).
13 . The hydroponic growing medium according to claim 1 , wherein the three-dimensional self-supporting substrate forms a propagation cube.
14 . The hydroponic growing medium according to claim 13 , wherein the propagation cube has a dry bulk density of about 3.6 lb/ft 3 (57.6 kg/m 3 ) to about 10 lb/ft 3 (160.185 kg/m 3 ).
15 . The hydroponic growing medium according to claim 1 , wherein the hydroponic growing medium is sterile.
16 . The hydroponic growing medium according to claim 1 , prepared by a process comprising:
combining a loose metered volume of the man-made fiber portion with the natural fiber portion and reducing the fiber to a predetermined thickness to form a compressed matrix,
exposing the compressed matrix to elevated temperatures to melt at least a portion of the fiber, and
applying pressure to the compressed matrix to generate the three-dimensional structure of the hydroponic growing medium.
17 . The hydroponic growing medium according to claim 16 , wherein the process further includes inserting the hydroponic growing medium in a plastic bag having one or more apertures.
18 . The hydroponic growing medium according to claim 16 , wherein the process further includes a sterilization and/or stabilization step.
19 . The hydroponic growing medium of claim 16 , wherein the compressed matrix has about 2.5 to 3.5 times the original bulk density of the loose metered volume of the fiber.
20 . The hydroponic growing medium of claim 16 , wherein the compressed matrix has a thickness which is about 100 to 500% of the original thickness of the loose metered volume.