IE48541B1 - Method of growing plants - Google Patents

Abstract

Plants are grown in shaped suitable substrates 16 which rest on a support 10. Between the support 10 and the substrates 16 are provided two nets 17, 18. Periodically the roots are sheared either by moving the nets relative to one another, or by the action of a blade or wire 14 moving between the nets. This shearing aids growth since the removal of each root tip results in the growth of several root tips.

Description

This invention relates to a method of growing plants, particularly forest plants.

In growing forest plants, whether in the open air in nurseries, or in greenhouses, one aims to provide a root system as richly branched as possible, comprising a largest possible number of active root tips. This is a prerequisite for plants to establish themselves quickly and reach a strong growth, after being planted on a final growing site.

One method of providing a richly branched out root 10 system is to prune the roots. This is because a root thathas its tip cut away or pruned, very quickly forms many new roots which, together, have a much higher ability to take up water and nutriment than the original root tip. However, due to several practical problems, root pruning has hitherto been utilized only to a very restricted extent, predominantly for experimental purposes.

We have now discovered a method of growing of plants, particularly forest plants, which can be suited for growing low-cost, high-quality plants, having enhanced growth capacity, and we have devised a growing unit having good handling and growth characteristics.

According to the invention there is provided a method for growing a plant, particularly a forest plant, wherein net is laid on a support bed and the plant is grown in a suitable growing medium placed on the net, such as in a disc or any other suitably shaped body of medium. The root system of the plant is periodically pruned by applying a shear force at the net.

The invention will now be described with reference to the accompanying drawings, in which: Figure 1 is a cross-sectional view of a growing bed and a plant assembly, which illustrates diagrammatically a basic principle for growing in accordance with the invention; Figure 2 is similar to Figure 1 but illustrates a plant in a different growing medium, and a method which is somewhat further developed than that shown in Figure 1; Figure 3 is a cross-sectional view of a greenhouse wherein the growing method according to the present invention can be carried out; Figure A is a perspective view of some growing containers of a conventional design; Figure 4 is a perspective view of some growing units suitable for use in the method according to the present invention; Figure 5 is a vertical cross-section of a growing unit suitable for use in the method according to the invention, immediately after sowing; and Figure 6 is a vertical cross-section of a growing unit suitable for use in the method according to the invention, immediately after sprouting.

Figure 1 schematically shows a bed 10 of an airy material, such as gravel or sand. On the bed 10 is laid a net, such as a plastics net of a suitable mesh, in the example shown the net 11 comprises overlapping net lengths 11A, 11B; if there are several net lengths or pieces then the overlapping is preferably arranged in substantially the same direction for a purpose which will be disclosed in more detail below.

In the example in Figure 1 the plants 12 are grown standing on the nets 11, and growing will take place in a disc 13. The disc is a shaped body of a suitable growing medium, covered by a moisture impermeable, preferably entirely watertight, cover which is downwardly open.

Therefore, the roots of the plant by geotropism and a suitable water balance will be directed downwardly and out through a hole, to grow downwardly into bed 10. Now, according to the present invention, with suitable intervals, the roots are pruned by shearing off the roots in one plane.

For example, shearing may be accomplished by a relative movement between the net 11 and the bed 10, for example by moving the net 11 along the bed 10.

The shearing effect may also be accomplished by moving a suitable shearing member, such as a knife, a thread or a wire between the net 11 and the bed 10. Xn the example shown a movement of the shearing member 14 in the direction of the arrow A is contemplated, in which case it is necessary that the net lengths overlap and are substantially parallel.

It should be pointed out that the root tips of the plants, besides branching out richly downwardly, are withheld from running round along the side edges and corners of the water-tight cover due to the fact that moisture conditions are more favourable downwardly towards the soil than within the water-tight cover. This is because of water condensation that takes place at the inner surface of the water-tight cover.

The example in Figure 2 is very similiar to the one in Figure 1, but the growing substrate is now a coherent pyramidal growing substrate body 16. This body is placed on two nets 17, 18, between which the shearing member 14 is moved in the direction of the arrow A to bring about root pruning by shearing in one plane. In this example it might also be possible to bring about a shearing of the root tips by a relative movement of the nets 17, 18, at suitable time intervals.

Of course, in both examples a very large number, such as several thousands, of growing substrate bodies may be placed side by side on the nets.

In the example in Figure 3 there has been arranged, on the floor 19 of the greenhouse, a suitable growing bed 20, comprising, for example, coarse gravel on which has been laid a plastics net of a suitable mesh. Then on the plastics net, there has been laid net pieces 21, such as of ordinary pallet size, χ 120 an. Each one of these net pieces may carry a plurality of growing substrate bodies, e.g. similar to the body 16 in Figure 2.

Along the sides of the greenhouse there run rails 23 for a transverse overhead crane 24 which carries a cutting device, schematically shown at 25, for root pruning at the under surfaces of the net pieces 21, in a manner similar to that which has been described above with reference to Figure 2. The cutting device may extend all along the full width of the greenhouse, or may it be of such a length that it performs the root pruning along only one longitudinal plant row at a time, as indicated in Figure 3. The transverse crane 24 should preferably be equipped with nozzles 26 for the application of, for example, water, nutriments and combating means, such as insecticides.

Furthermore, the crane 24 is preferably provided with lifting means 27 to permit easy distribution of the net pieces with the growing substrate bodies resting thereon, and then an easy lifting and removal of them from the greenhouse for transport to a planting site.

Figure A shows three containers 30 containing a suitable growing substrate 31, such as peat moss or the like. In each one of the containers 30 a plant 32 has been grown.

Figures 4 and 5 illustrate three growing units suitable for use in the method according to the present invention. Each one comprises a cover 33 containing a filling 34 of a suitable growing substrate, such as peat moss, mineral rich soil, mineral wool or suitable mixtures thereof. The growing substrate may also comprise nutriments and combating agents, such as fungicides.

The containers 33 preferably consist of a form pressed mixture of peat moss and cellulose, and the containers are shown as being square frusto pyramids, but other shapes may be used. However, it would appear to be particularly advantageous to design the containers in such a manner that the bottom surface 35 is considerably bigger than the top surface 36.

A manufacture of the containers 33 in situ is also contemplated, e.g. in that a plurality of substrate bodies are form pressed, for instance into a general shape as shown in Figure 4. These bodies, disposed side by side as shown in Figure 4, are then provided with a suitable surface coating which upon drying or hardening forms the containers in question. The individual growing substrate bodies, being provided with the cover in situ, may then be separated from each other, prior to providing the units with seeds or cut off shoots.

As mentioned above, Figure 5 shows a growing body which in an upper recess 37, has been provided with a seed 38 which has developed a first root thread 39 and has thrown off its shell 40. A plurality of growing substrate bodies, placed side by side, are covered by means of a suitable net 41 as a protection against attacks by birds, rodents and the like.

Figure 6 is a vertical cross-section illustrating a growing substrate body wherein the plant 42 has developed a very richly branched out root system 43 which has been enhanced by root pruning as described above.

The particular growing unit that has been described has the advantage that comparatively stiff. container walls can without fail maintain the plants separated from each other. The substrate body, which protrudes upwardly from the supporting surface, is accessible to the surrounding air from all directions other than from below. As the ambient air is normally hotter than the soil, this accessability enhances a quicker germination and an improved growth, compared with prior art growing units.

Propagation of roots from one container to an adjacent one may be controlled by regulation of the humidity and, if desired, it may be prevented entirely, which facilitates the separation of the plants from each other when they are to be picked up for transport to a planting site.

Because of the shape of the containers illustrated, the growing units may very easily be picked up mechanically for transport to a planting site.

The illustrated outer shape of the growing units is very advantageous with respect to planting on sites where there otherwise exists a risk of freezing, due to the so called fluted ruff effect, as the frusto conical shape serves to hold down the substrate bodies.

Preferably, the holes 37 for the seed 38 are downwardly conically tapering and of sufficient depth, so that the seeds may germinate in the adequate humidity which prevails within the unit and so that the seedling gets enough time to stabilize itself and assume a certain inherent force before the plant reaches the upper edges of the hole. In this way the seeds and seedlings may very easily be protected by means of an overlying net 41 from attacks by birds and rodents, if desired, until the seedling has grown to a size at which it is not longer attractive to such beasts.

It is comparatively easy to maintain the container wall at such humidity that the roots grow essentially downwardly, due to positive geotropism.

By suitable choice of material for the containers 33 the containers, after drying out, may give protection against evaporation of the moisture that the substrate body absorbs from its supporting surface.

As is shown in Figure 6 the growing substrate unit is ideal for the root pruning described. Due to the very richly branched root system obtained it will be enough, when transplanting, just to place the substrate body on the soil, which has in advance been suitably prepared. If desired, only the lowermost portions of the substrate body may be covered by, for example, a mineral soil. In this manner, the substrate body gets a very satisfying and advantageous heating, since the protruding portions of the substrate body are readily accessible to the surrounding normally hotter air.

The containers 33 may, of course, be manufactured by mass manufacturing processes in different sizes and qualities, such as in quantities up to about 50 000 units per hour.

Claims (6)

1. A method of growing a plant wherein net is laid on a support bed, a plant is grown up in a suitable growing medium placed on the net, and the root system of the plant is periodically pruned by applying a shear force at the net.

2. A method according to Claim 1, in which a bed of gravel is used at the support bed, and shearing is brought about by periodically moving the net in relation to the bed.

3. A method according to Claim 1, in which a bed of gravel is used as the support bed, and shearing is brought about by periodically moving a cutting device along the under surface of the net.

4. A method according to Claim 1, in which a bed of gravel is used as the support bed, the net laid on the bed comprises a first net and a second net disposed between the first net and the bed, and shearing is brought about by periodically moving the nets in relation to each other.

5. A method as claimed in Claim 4, in which a bed of gravel is used as the support bed, the net laid on the bed comprises a first net and a second net disposed between the first net and the bed, and shearing is brought about by periodically moving a cutting manber between the nets.

6. A method of growing plants substantially as herein described with reference to any one of Figures 1-6 of the accompanying drawings.