WO2012121592A1

WO2012121592A1 - A method for producing culture media for cultivating plants, and a culture medium

Info

Publication number: WO2012121592A1
Application number: PCT/NL2012/050127
Authority: WO
Inventors: Lucas Everhardus Maria Langezaal; Adriaan Lucas LANGEZAAL
Original assignee: Lucas Everhardus Maria Langezaal
Priority date: 2011-03-04
Filing date: 2012-03-02
Publication date: 2012-09-13
Also published as: NL2006340C2

Abstract

A method for producing culture media for cultivating plants (29, wherein the culture media are substantially made of a growth substrate (1), wherein use is made of a container which is open at the upper side and which is filled with the growth substrate, wherein the inner side wall of the container is at least partially provided with a powder and/or with fibres before the container is filled with the growth substrate (1), and wherein the powder and/or the fibres are formed into a bandage, using a heat treatment or a chemical reaction, after the containers have been filled with the growth substrate, which bandage (3) forms a circumferential wall of the culture medium.

Description

A method for producing culture media for cultivating plants , and a culture medium

The present invention relates to a method for producing culture media for cultivating plants, wherein the culture media are substantially made of a growth substrate, wherein use is made of a container which is open at the upper side and which is filled with the growth substrate. Such a method is known from WO 2007/011225. The culture medium may be a so-called substrate plug, for example, usually of frustoconical shape, having a height of about 5 cm and an average diameter of about 3 cm, or a so-called cultivating block which is intended to receive at least one substrate plug, usually in block form, for example measuring 9 cm x 9 cm x 9 cm or more.

In the production of substrate plugs, use is made of trays comprising a multitude of containers which are filled with loose soil, peat, etc, with glue plugs, or with paper cases containing soil, peat, etc, in which a seed or a germinated plant is placed.

The use of loose soil has the drawback that the soil falls apart when the young plant is being transplanted, and that it is not possible to place said unit in a container having a larger volume without the unit falling apart. Furthermore it is not possible to use an automated transplanting process, because the pin that is to push the unit up from the container disappears into the loose soil, breaking up the unit, or because the gripper that picks up the unit breaks up the unit.

The use of a glue plug, in which the loose soil is mixed with glue, has the drawback that the plug breaks open upon insertion of a cutting, if the plug is not contained in a container having the same dimension as the plug. Furthermore, the use of a large amount of glue does not have a positive effect on the growth of the plant. Drawbacks of the use of a paper case include the fact that the soil can fall from the case, that only cylindrical shapes are possible and that fungal growth may occur.

The object of the present invention is to provide an alternative method and an alternative culture medium which at least partially obviates the aforesaid drawbacks.

In order to accomplish that object, the inner side wall of the container is at least partially provided with a powder and/or with fibres before the container is filled with the growth substrate, which powder and/or which fibres are formed into a bandage, using a heat treatment or a chemical reaction, after the containers have been filled with the growth substrate, which bandage forms a circumferential wall of the culture medium. The reinforcement thus provided can be selectively provided on the inner side wall at locations desired for the purpose in mind, and thus be arranged around the growth substrate. In this way less glue, or no glue, is needed in the growth substrate, for example. The bandage preferably extends annularly against one or more parts of the side wall of the culture medium, so that the culture medium will not tear or fall apart. In a preferred embodiment, the bandage extends at least partially against the underside and the lower part of the side wall of the culture medium, so that the pin that pushes against the underside will not damage the culture medium, for example during automatic repotting. In another preferred embodiment, the bandage forms an open network, so that the bandage will not impede root growth therethrough and the water absorption will be optimal. The entire bandage can function as a tray wall, so that the culture medium can be freely suspended in containers, which significantly simplifies the process of transplanting the plants.

Any desired shape of the container may be used and, using the pattern of the cover of the holder, any desired bandage pattern can be provided.

Before the inner side wall of the container is provided with the powder and/or the fibres, the inner side wall is preferably provided with a release agent. The release agent is preferably a moist release agent, so that the powder and/or the fibres will bond thereto upon application.

After the heat treatment, the container is preferably cooled, using cold water. The powder and/or the fibre material is preferably a

thermoplastic material, which is formed into a bandage using a heat treatment. The thermoplastic material preferably melts at a temperature between 50 °C and 90 °C, more preferably between 50 °C and 70 °C, even more preferably between 50 °C and 60 °C. The grain size of the powder preferably ranges between 10 μιη and 200 μιη. The material is preferably selected from the group comprising: EVA, polyester-epoxy, polyethylene, polypropylene, TPU, COPA, COPES, HDPE, modified PE, CDPE, a biodegradable material. The biodegradable material, which has the advantage that it can be planted into the ground without any problem and that it does not comprise any residual materials that burden the environment, is preferably selected from the group comprising: caprolactones , ; biodegradable polyester, such as statistic, aliphatic aromatic copolyesters based on the various monomers of butanediol, adipic acid and terephthalic acid; polyactic components; polyhydroxybutyrate (PHB) components;

polyhydroxyalkanoate (PHA) components; starch components.

The invention further relates to a culture medium for cultivating plants, which culture medium is substantially made of a growth substrate, characterised in that the circumferential wall of the growth substrate is at least partially made up of a bandage formed on the circumferential wall of the growth substrate by melting or by a chemical reaction of powder and/or fibres.

The invention will be explained in more detail below with reference to embodiments shown in the figures, in which:

Figure 1 is a front view of a first embodiment of a culture medium according to the invention; and

Figures 2A, 2B, 2C and 2D are perspective views of further embodiments of the culture medium according to the invention.

According to figure 1, a culture medium comprises a substantially frustonical growth substrate 1 with a plant 2, which, according to the method described herein, is partially enveloped by a bandage 3. In this embodiment, the sleeve-like bandage 3 abuts against the lower half of the side wall of the culture medium.

According to the embodiment shown in figure 2A, the culture medium is substantially cylindrical in shape, and the

sleeve-like bandage 3 abuts against the upper half of the side wall of the culture medium, so that the culture medium will be strengthened when a big cutting is inserted therein. According to the embodiment shown in figure 2B, the culture medium is of substantially square section, and the sleeve-like bandage 3 abuts against substantially the entire side wall of the culture medium.

According to the embodiment shown in figure 2C, the culture medium is substantially frustoconical in shape, and the sleeve-like bandage 3 abuts against substantially the underside of the side wall as well as against the underside of the culture medium, whilst a hole 4 is left open in the centre for the passage of water.

According to the embodiment shown in figure 2D, the culture medium is substantially hexagonal-frusto-pyramidal in shape, and the sleeve-like bandage 3 abuts against substantially the entire side wall of the culture medium.

The culture media shown herein can be produced in the following manner. Use is made of a tray comprising containers having the desired shape of the culture medium, which containers are open at the upper side. The inner wall of the containers is provided with a moist release agent, as known in the art.

Following that, the moist inner wall is partially covered, so that the melt powder or the melt fibre will only come into contact with the parts of the culture media that are indicated in the figures. Thus, using a grid-like covering of the wall, a grid-like layer could be provided by sprinkling, thus forming a gauze-like bandage. Following the application thereof, a melt powder, with or without fine fibres, or a melt fibre, is sprinkled on the moist inner wall of the containers. The melt powder or the melt fibre sticks to the release agent. In order to prevent the powder and the release agent from being wiped off the wall during a subsequent production stage, limited drying, using a heat treatment, takes place first. The tray is subsequently filled with a glue/substrate mixture or with loose soil or a peat mixture. Depending on the type of glue in the substrate mixture that is used, a chemical reaction or a temperature treatment will be started.

Both in the case of loose soil plugs and in the case of glue plugs, a temperature treatment will subsequently take place so as to cause the melt powder/melt fibre that adheres to the release agent to start bonding.

Upon heating, the material will liquefy and bond to the plug wall . In addition to the material granules or fibres bonding to the plug, a mutual contact is created as a result of the deliquescence of the granules or fibres. After heating, the tray and the plug can cool down, thereby fixing the bond. This process can be accelerated by pouring cold water thereon. The plugs can be produced in their definitive tray or in a production mould and subsequently be placed in the final tray in case plugs separate from the wall are wanted.

The properties of the bandage are determined by a group of variable characteristics being used, such as:

1. Melting range of the material

2. Thickness of the release agent

3. Melt index of the material

4. Grain size or fibre size of the material

In order to ensure that this process can be carried out for any tray or container type, it is preferable to use a material having a relatively low melting range in connection with heating the tray or the container, preferably 50-90 °C, more preferably 50-70 °C, whilst preferably 50-60 °C.

The thickness of the release agent partially determines the thickness of the bandage, since more grains will remain stuck in the fluid if more release agent is used.

Example : For a practical embodiment, an EV thermoplastic having a melt index of 400, a melting range of 55-62° and a grain size of 10-200 ym, the larger percentage having a grain size of around 120 ym, was selected. Said powder was sprinkled onto a container wall treated with a release agent. The container had a volume of 12 cm³ and a height of 36 mm. A liberal mount was sprinkled onto the container, the excess grains being blown out by means of a small amount of air. An amount of 0.1 g of EVA remained behind on the wall. Said amount provides a complete, strong bandage around the culture medium and has a limited porosity. The high melt index and the large amount of the fine grains of fibres in this case result in a significant deliquescence of the material. If an amount of 0.5 g of material is sprinkled on the same area, a considerably more open bandage is obtained. Said bandage still imparts extra strength to the plug. A powder having a larger grain size and the same melt index will provide a thick bandage and thus be stronger.

Claims

1. A method for producing culture media for cultivating plants, wherein the culture media are substantially made of a growth substrate, wherein use is made of a container which is open at the upper side and which is filled with the growth substrate, characterised in that the inner side wall of the container is at least partially provided with a powder and/or with fibres before the container is filled with the growth substrate, and that the powder and/or the fibres are formed into a bandage, using a heat treatment or a chemical reaction, after the containers have been filled with the growth substrate, which bandage forms a circumferential wall of the culture medium.

2. A method according to claim 1, wherein the inner side wall is provided with a release agent before the inner side wall of the container is provided with the powder and/or the fibres .

3. A method according to claim 2, wherein the release agent is a moist release agent, so that the powder and/or the fibres will bond thereto upon application.

4. A method according to claim 1, 2 or 3, wherein the powder and/or the fibre material is a thermoplastic material, which is formed into a bandage using a heat treatment.

5. A method according to claim 4, wherein the thermoplastic material melts at a temperature between 50 °C and 90 °C, preferably between 50 °C and 70 °C, more preferably between 50 °C and 60 °C.

6. A method according to claim 4 or 5, wherein the container is cooled, using cold water, after the heat treatment.

7. A method according to any one of the preceding claims, wherein the grain size of the powder ranges between 10 μιη and 200 μιη.

8. A method according to any one of the preceding claims, wherein the bandage extends annularly against one or more parts of the side wall of the culture medium.

9. A method according to any one of the preceding claims, wherein the bandage forms an open network.

10. A method according to any one of the preceding claims, wherein the bandage extends at least partially against the underside and the lower part of the side wall of the culture medium.

11. A method according to any one of the preceding claims, wherein the material is selected from the group comprising: EVA, polyester-epoxy, polyethylene, polypropylene, TPU, COPA, COPES, HDPE, modified PE, CDPE, a biodegradable material .

12. A method according to claim 11, wherein the material is a biodegradable material, which is selected from the group comprising: caprolactones, ; biodegradable polyester, such as statistic aliphatic aromatic copolyesters based on the various monomers of butanediol, adipic acid and

terephthalic acid; polyactic components;

polyhydroxybutyrate (PHB) components;

polyhydroxyalkanoate (PHA) components; starch components.

13. A culture medium for cultivating plants, wherein the culture medium is substantially made of a growth substrate, characterised in that the circumferential wall of the growth substrate is at least partially made up of a bandage formed on the circumferential wall of the growth substrate by melting or by a chemical reaction of powder and/or fibres .

14. A culture medium according to claim 13, wherein the culture medium is a cultivating plug.

15. A culture medium according to claim 13, wherein the culture medium is a cultivating block intended for receiving at least one cultivating plug.