Root fertilizing device

The device is a cylindrical housing enclosing a spaced apart cylindrical receptacle for fertilizer. Metering rings channel rain water towards the fertilizer but prevent fertilizer from exiting the top of the housing. End grates enclose the open ends of the housing, the top grate containing a water permeable filter to prevent clogging of the device by foreign debris.

DESCRIPTION 
1. Technical Field 
This invention relates to a root fertilizing device. More particularly, it 
refers to a device for insertion into the ground along the drip line of a 
tree to continuously provide fertilizer from an interior of the device to 
leach into the tree root system. 
2. Background Art 
The prior art is replete with descriptions of devices containing 
fertilizer, usually cylindrical in shape, inserted into the ground for 
feeding root systems. Examples of these devices can be seen in the 
following patents: 
U.S. Pat. Nos.: 73,442 
349,874 
419,242 
790,910 
1,029,107 
1,490,865 
1,530,109 
1,971,390 
2,380,721 
2,791,347 
3,060,012 
3,319,379 
3,755,966 and 
Hungarian Pat. No.: 125,381. 
Of particular interest to the present invention are U.S. Pat. No. 3,319,379 
and No. 3,755,966. The former patent describes a fertilizing device having 
an outer cylindrical tube and an inner hollow cylindrical tube with a 
fluted bottom edge to allow fertilizer granules to mix with water flowing 
down a space between the outer and inner tube. The device also has a 
screen member at its top. The latter patent also describes a cylindrical 
outer tube and a cylindrical inner tube. The inner tube has an upper 
outward flange, allowing it to rest on an upper stepped section of the 
outer cylindrical tube. Although both these patents describe tree 
fertilizing devices, they suffer from limitations. The former patent 
describes a device that allows fertilizer to dissipate too rapidly if the 
surrounding soil is sandy. The latter patent describes a device that may 
fill up with water during a severe rain storm and permit fertilizer to 
float to the surface and be washed away without providing benefit to the 
intended tree root system. 
SUMMARY OF THE INVENTION 
I have invented a root feeder that solves the problems with the prior art 
devices and provides a device that feeds roots in all types of soil 
without permitting fertilizer to be dissipated by surface water runoff. 
My device contains a cylindrical outer housing open at both ends and a 
cylindrical inner fertilizer receptacle open at both ends and spaced apart 
from an inner side wall of the outer housing. A first metering ring having 
a top surface tapered inwardly is fit into the top of the inner receptacle 
and a flat second metering ring is fit into a bottom of the inner 
receptacle. The inner receptacle together with the end rings is fit within 
the outer housing so that a water conducting channel surrounds the inner 
receptacle. A top grate having a water permeable filter encloses the top 
of the outer cylinder and a bottom grate having a multiplicity of holes on 
its outer edge encloses the bottom of the outer cylinder. Fertilizer is 
added to the inner receptacle on a preset schedule of about once each 
quarter to continuously make fertilizer available for the roots when the 
device is inserted in a hole along the drip line of a tree or large bush.

DETAILED DESCRIPTION OF THE INVENTION 
Throughout the following detailed description the same reference numerals 
refer to the same elements in all figures. 
The root fertilizing device 10 of this invention is inserted into a hole in 
soil 12 or concrete 14 under the drip line 16 of a tree 18 or under a 
large bush. In a preferred embodiment, it is necessary to put a layer of 
gravel 20 at the bottom of the hole so that the root feeding device 10 can 
rest on top of the gravel and have its top grate 22 flush with the surface 
of the concrete 14 or soil 12. Rain falling down into the root feeding 
device 10 passes through fertilizer 24 located within an inner cylindrical 
receptacle 26 which in turn is mounted within an outer cylindrical housing 
28. The rain falling through the fertilizer 24 flushes it out at a slow 
pace as will be described in more detail hereafter. In this manner the 
fertilizer slowly feeds the roots 30 of tree 18. 
The outer cylindrical housing 28 has an exterior wall 32 and an interior 
wall 34 and is open at a top end 36 and a bottom end 38. 
The inner cylindrical receptacle 26 is mounted within but spaced apart from 
the inner wall 34 of housing 28. The inner cylindrical receptacle 26 has 
an exterior wall 40 and an inner wall 42 with a plurality of notches 44 
traversing through exterior wall 40 and interior wall 42 at a first end 46 
and at a second end 48. 
A top metering ring 50 is mounted at the base of the notches 44 flush 
against spokes 45 in the first open end 46 of receptacle 26. The top 
surface 52 of metering ring 50 tapers in a downward direction from inner 
wall 34 of housing 28 to the outer wall 40 of receptacle 26. The top 
metering ring 50 also has a plurality of holes 54 through the ring surface 
to allow water overflowing from inner receptacle 26 to flow down through 
chamber 56 and then out through the bottom openings 78 of bottom grate 76. 
A bottom planer metering ring 60 is mounted at the base of notches 44 flush 
against spokes 47 in the second end 48 of receptacle 26. This metering 
ring also has holes 62 for allowing water to flow through while at the 
same time maintaining channel 56 and the space relationship of receptacle 
26 from the inside wall 34 of housing 28. 
The top grate 22 acts as a cover over end 36 of housing 28. This top grate 
22 has a plurality of holes 66 throughout its top surface 67 and a screen 
68 just below the holes. Below the screen 68 is a fiberglass filter 70 
held in place by a thin holding plate 72 having multiple holes therein. 
This top grate 22 allows moisture into the root feeding device 10 of the 
invention but prevents entry into it of foreign particles such as mud and 
debris of a general nature. The fiberglass filter 70 can be replaced 
periodically by pulling out holding plate 72. It is suggested that the 
filter be replaced at least once per quarter when fertilizer is inserted 
into receptacle 26. The top grate 22 is removed by inserting a tool into 
hole 66 and pulling up. The inner receptacle 24 can then be filled with 
fertilizer and grate 22 is replaced merely by pushing down to press fit 
the grate on the inner surface 34 of the top end 36 of housing 28. 
A bottom grate 76 having peripheral holes 78 is snapped over the bottom 38 
of housing 28. The central or core portion of bottom grate 76 is solid and 
therefore prevents fertilizer from falling directly out from receptacle 
26. Rather, the fertilizer must be metered out through metering ring 60 
and then through the holes 78 along the outer edge of bottom grate 76. 
This controls the amount of fertilizer leaving the device and prevents 
large amounts from exiting after a substantial downpour. Excess water 
passes through channel 56 and exits through holes 78 in grate 76. 
The outer housing 28, the receptacle 26, the metering rings 50 and 60, as 
well as the grates 22 and 76 are all made of a high strength plastic such 
as polyvinylchloride polymer, a reinforced polyethylene polymer or a 
polyacrylic polymer. A higher strength polymer will be necessary for use 
on tree feeding devices 10 employed with concrete surfaces where heavy 
loads are expected from automobiles or trucks. The top surface of grate 22 
can be scratched to provide a rough surface to prevent anyone walking 
across the grate 22 from slipping. The fertilizer employed can be any of 
the types having well known adaptability in the tree feeding arts. 
My device provides a method by which fertilizer retained within the 
receptacle 26 is metered out at a usable rate for the roots of trees or 
large bushes under which the device 10 is inserted. The channel 56 
provides a route for excess water to move out from the recepticle without 
unduly diluting the fertilizer. The grate 76 prevents large amounts of 
fertilizer from exiting from the bottom of device 10 during heavy 
rainfalls. Rather, the fertilizer mixed with water must exit through holes 
78 in grate 76. Finally, the top grate 22 provides a means for preventing 
contamination of my device from foreign particles such as seeds, buds and 
other debris that might be occasioned by heavy rainfalls to wash into 
device 10. The simplicity of the parts and the ability to press fit the 
various parts together allows for the production of an inexpensive root 
feeding device. 
It can be understood that the present invention describing a root feeding 
device can be made using equivalent parts without departing from the basic 
inventive concept.