CA1185793A

CA1185793A - Horticultural ground cover

Info

Publication number: CA1185793A
Application number: CA000447868A
Authority: CA
Inventors: Peter Sawrenko
Original assignee: Individual
Current assignee: Individual
Priority date: 1983-10-31
Filing date: 1984-02-21
Publication date: 1985-04-23

Abstract

ABSTRACT OF THE DISCLOSURE

A horticultural ground cover for gardens or any other area where it is desired to prevent the growth of undesirable vegetation but promote the growth of desirable vegetation. A horticultural ground sheet comprises a flexible sheet of opaque material, for example black polyethylene film, interspersed with a plurality of slits.
These slits must prevent as much as possible the entry of undesirable plant seeds but permit the entry of air and water to allow the desired plants to grow. The ground cover prevents the growth of plant shoots beneath it.
Openings are formed to allow desired vegetation to grow.

Description

,i,:.6,~ :

3276~5 This invention relates to a horticultural ground sheet for preventing the seeding and growth of undesirable weeds in gardens or in any cultivated area reserved for the growth of desired vegetation.
Gardeners frequently use ordinary polyethylene film, known in the building trade as vapour barrier, as a ground cover. This film, which is usually black and imper-meable to light r is spread over the garden area and ope-nings are cut in it with a sharp utensil where one wishes to plant either seeds or seedlings. The seeds or seedlings are then pushed through the openings into the soil below.
This sheet, while it is moderately successful in preventing the growth of weedis, is unsuccessful in promoting growth of the desired vegetation for the following reasons. First ~5 the small space between the stem of the seedling and the edges of the opening in the sheet often prevents adequate water flow to the soil underneath. Thus seedlings are deprived of water, which is of course essential to their growth. Further if the seedling does grow, sooner or later the stem will itself begin to seal the opening cut in the sheet, further compounding the problem. Enlarging the opening in the sheet is not a worthwhile solution as the hole reqjuired would become so large as to allow for the germination of weeds, thus negating the purpose of the ~5'7~

sheet in the first place.
Secondly beneEicial air circulation in and around the seedlings and soil is greatly reduced.
Owing to the above conditions souring or acidity of the soil occurs and undesirable mildew and moss growth is promoted, principally due to the lack of proper air cir-culation. The amount of opacity oF a thin plastic sheet is sometimes insufficient to prevent the growth of weeds that can survive even in the presence of small amounts of water. Indeed the inventor has found that weeds or any other common vegetation require a minimum of about 500 foot candles of light to grow. Some of the sheets currently used do not permit this much light to pass. Allowing more than 500 foot candles of light to penetrate the surface can ~5 allow undesirable weed growth beneath the cover.
The present invention seeks to overcome the problems with the prior art by providing a thin but opaque sheet, for example polyethylene, interspersed with a plura-lity of slits, over its surface.
More specifically the present invention is a hor-ticultural ground sheet comprising a flexible, sheet of an opaque material, the sheet being formed with a plurality of slits, the slits being of such dimensions that water and air can pass through the sheet but plant shoots cannot grow up through the sheet and plant seeds cannot pass down through the sheet.

:

, In a desirable embodiment the sheet may be formed with larger openings, to be cut in the sheet when it is placed over a garden, so that seeds and seedlings may be pushed through these holes into the soil below. It should be emphasized that such larger openings can, if desired, be provided on the production line.
The sheet will typically be made of a plastic that is as cheap as possible yet able to carry out the required function. Polyethylene has been found to be ideal. A black polyethylene sheet has been used in experiments. Such a sheet is substantially completely opa-que to light and the slits formed in it was such that the light that passed through did not exceed about 500 foot candles. Any colour of sheet that is opaque will generally be adequate. Black will, of course, absorb heat and it may be desirable to heat the soil so that the use of a black horticultural ground sheet according to the present inven-tion will provide advantages. In other circumstances a lighter coloured, but still opaque, sheet may be used in order to avoid heating the soil. Thus the colour can vary from black through gray to white to vary heat absorption characteristics.
Aspects of the invention are illustrated in the drawings in which:
Figure 1 is a general view showing a ground sheet according to the present invention in use;

7~33 Figures 2 and 3 illustrate various patterns of openings that may be used; and Figure 4 illustrates a means of locating and maintaining ~he larger openings necessary to permit planting of the desired plants.
The drawings show a horticultural ground sheet 2 comprising a flexible sheet of an opaque material, typi-cally polyethylene. The sheet is formed with a plurality of slits 4 that are of such dimensions that water and air can pass through the sheet but plant seeds cannot.
The opacity of the sheet is such that it will not allow more than 500 foot candles of light to pass.
Figures 2 and 3 illustrates various patterns of slits 4 that have proved useful In Figure 2 the slits 4 are regular elongated slits and in Figure 3 relatively irregular slits. It has been found that slits of approxi-mately 2 to 6mm, preferably 3mm, in length are desirable.
Figure 4 illustrates the formation of larger ope-ning~ 6. These larger openings 6, which are for the planting of desired plants 8 (see Figure l), are maintained by the use of clips lO. These clips 10 comprise wire bodies having limbs 12 extending downwardly to penetrate the soil 14. They maintain the position of the sheet 2 and thus prevent the sheet 2 from interfering with the growth of the desired plant 8. As illustrated in Figure l the sheet may, of course, be retained in position by use of .~

;7~3 weights 16, for example stones.
To use the sheet of the present invention an area of cultivated ground is covered with the sheet 2 according to the invention. Openings 6 may be formed, or will already be formed, to receive desired plants 8. Once the desired plants 8 are planted rings 10 are positioned to maintain the openings 6.
In trials conducted the sheets 2 have proved a considerable success. In a spring growing season an area of approximately 900 sq. ft. was covered with sheet 2.
Openings 6 were formed and tomato plants planted. During the whole growing season four weeds were observed. One was a blade of grass and the three others weeds were of a type wlth which the area planted was previously infested.
~S The sheet according to the present invention may be made by conventional methods well known to the plastics manufacturer. The slits 4 may be formed in the sheet imme-diately after production of the sheet, for example by passing the sheet over a roll having cutting projections ~ formed in the desired pattern.
The present invention thus provides a simple means of greatly improving the yield from any given area of ground. It is particularly desirable in horticultural use, for example for domestic gardens. The sheet is such that watering may be carried out conventionally. That is water applied to the sheet passes through and is absorbed by the ., soil. The sheet may be left on in the winter to prevent weeds re-establishing themselves. The sheet may also act as a mulch for the soil.
The sheet may be used as a base material beneath stones or bark mulch where its ability to allow water to pass yet suppress weed growth is an advantage.

Claims

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. A horticultural ground sheet comprising of flexible sheet of a substantially opaque material, the sheet being formed with a plurality of slits, each slit being about 2 to 6 millimeters in length and thus able to permit water and air to pass through the sheet but to pre-vent plant seeds growing up through the sheet and plant seeds passing down through the sheet, the provision of slits modifying the opaque material so that the ground sheet will not allow more than about 500 foot candles of light to penetrate the sheet.

2. A sheet as claimed in claim 1 made of polyethylene.

3. A sheet as claimed in claim 1 of a black plastic material.

4. A sheet as claimed in claim 1 whose colour is chosen to provide a desired level of heat absorption.

5. A sheet as claimed in claim 1 including, in addition to the slits, openings large enough to receive a desired plant to be planted.

6. A sheet as claimed in claim 5 in combination with clips able to prevent the edges of the sheet surrounding the opening from blocking the openings and interfering with the growth of the desired plant.

7. A sheet as claimed in claim 6 in which each clip comprises a wire body having limbs extending from it, the limbs being adapted to pierce the ground adjacent the opening to allow the wire body to prevent closing of the opening in the sheet.

8. A sheet as claimed in claim 1 in which the slits are about 3mm long.

9. A method of preventing the growth of weeds in a plot of land, the method comprising covering the plot of land with a horticultural ground sheet comprising a flexible, sheet of a substantially opaque material, the sheet being formed with a plurality of slits, the slits being about two to six millimeters long and such that water and air can pass through the sheet but plant seeds cannot grow up through the sheet and plant seeds cannot pass down through the sheet, the provision of slits modifying the opaque material so that the ground sheet will not allow more than about 500 foot candles of light to penetrate the sheet.