GB2131662A

GB2131662A - Plant pots

Info

Publication number: GB2131662A
Application number: GB08235795A
Authority: GB
Inventors: Philip Hutchinson
Original assignee: Individual
Current assignee: Individual
Priority date: 1982-12-16
Filing date: 1982-12-16
Publication date: 1984-06-27

Abstract

A plant pot 1 comprises a cylindrical body 2 of circular cross- section, which is slit along its length so that it may be expanded and compressed radially. A constraining ring 3 passes around the body 2. In use, a Dahlia tuber is planted within the plant pot 1, in suitable compost. As it grows, the tuber expands in the plant pot 1 and becomes increasingly constrained under pressure therein. To remove the tuber from the plant pot, the constraining ring 3 is removed from around the cylindrical body 2, whereupon the pressure of the plant pot 1 upon the tuber is sufficiently released to allow the tuber to be removed. The plant pot 1 may be used to grow Dahlias of consistent and uniform appearance, and with reduced likelihood of afflictions. <IMAGE>

Description

SPECIFICATION Plant pots This invention relates to plant pots, and is particularly although not exclusively concerned with the growing of Dahlia tubers.

The growing of Dahlia tubers in this country (as in many other countries) is very labour intensive.

Dahlias are only half-hardy plants. They have to be planted out each year, and the tubers have to be lifted in Autumn, for storage for the next year.

Commercial growers can grow many thousands of tubers annually, each of which has to be lifted at Autumn. Dahlias are not only grown for their flowers. A large amount of the effort of commercial growers goes into producing tubers for sale.

The most usual way of growing Dahlias is to plant them in open ground. The disadvantage of this is that the tubers tend to grow quite large and the ground roots spread considerably. As a result, they become very difficult to lift and handle, and once lifted, tend to dry out quickly, and to be susceptible to disease, particularly if broken.

Some growers do plant their Dahlia tubers out in plastic or clay pots, which may themselves be then put into the ground. However, because of the growth rate of the tubers, such plastic and clay pots readily break, and they have not been found to be very successful in containing Dahlia tubers, unless the tubers are kept very small. Also, when tubers are contained in conventional plastic or clay pots, the growth of the feeding roots, which wish to grow downwards, is very much restricted, and therefore tubers kept in pots tend to require considerably more careful watering, especially when grown out of the ground.

Where a commercial grower is producing tubers for sale, it is a desirable feature of the tubers to have a consistent and uniform appearance. This is virtually impossible to achieve if the Dahlias are planted out in open ground, and as will be apparent from the above, attempts to contain the tubers within pots have generally met with little success.

Preferred embodiments of the present invention aim to provide plant pots which may be used for growing Dahlia tubers, in a much more successful manner.

More generally, according to a first aspect of the present invention, there is provided a plant pot comprising an expandable tubular body and a constraining member which passes around said body to constrain its expansion but is releasable so as to release such constraint.

Preferably, the tubular body is cylindrical, and may with advantage be of circular cross-section.

The tubular body is preferably elongate.

In a preferred arrangement, the tubular body is split from top to bottom, so as to be expandable.

In such an arrangement, the tubular body may have wall portions which overlap at the split.

The constraining member is preferably an annular member which is adapted to fit around the tubular body, intermediate the top and bottom thereof. The tubular body and the constraining member preferably have generally the same shape in cross-section.

The tubular body is preferably open at top and bottom.

Preferably, the bottom of the tubular body is partly closed by a closure member. The closure member may be a plate and may have a polygonal cross-section whereas the tubular body has a circular cross-section, or vice versa. The polygonal cross-section may be hexagonal or octagonal.

Preferably, wires cross the bottom of the tubular body, and serve to restrict expansion thereof. The wires may with advantage support the aforementioned closure member.

The tubular body and/or the constraining member may with advantage be made of a plastics material, such as a semi-rigid plastics material of significant thickness, of the type used, for example, in underground plastics ducts.

In fact, the tubular body and/or the constraining member may be cut from an extruded pipe, to appropriate lengths. The tubular body may be then slit along its length.

The size of the tubular body may be important.

Preferably, its length is substantially in the range ten to twenty centimetres, and with particular advantage is substantially in the range fourteen to sixteen centimetres. Preferably, the diameter of the tubular body is substantially in the range five to fifteen centimetres, and with particular advantage, substantially in the range seven to ten centimetres.

The plant pot may with advantage be provided with a further body similar to the first-mentioned tubular body and adapted to fit therearound to abut the constraining member such that a force may be transmitted to the constraining member via the further body, to dislodge the constraining member from around the first-mentioned body.

According to a second aspect of the present invention, there is provided a method of growing a tuber, comprising the steps of planting the tuber of a plant in a plant pot according to the first aspect of the invention, allowing the tube to grow until it is constrained within the plant pot under pressure, subsequently releasing the constraining member around the body of the plant pot, and removing the tuber from the plant pot.

For a better understanding of the invention and to show how the same may be carried into effect, reference will now be made, by way of example, to the accompanying diagrammatic drawings, in which: Figure 1 illustrates a plant pot in accordance with the invention, in front elevation; and Figure 2 is a top plan view of the plant pot, with a constraining member thereof removed.

The illustrated plant pot 1 comprises an elongate tubular body 2 of circular cross-section.

A constraining member in the form of a ring 3 passes around the tubular body 2 at approximately the centre portion thereof.

In a particularly convenient manner, both the tubular body 2 and the ring 3 are manufactured from a length of extruded piping, preferably of the black plastics type of piping which is used underground. In order to manufacture the body 2, an approximately fifteen centimetre length of pipe is cut off, and this is then slit along its length. The ring 3 is produced simply by cutting off an approximately three centimetre length of the pipe.

The slit which is formed along its whole length allows the tubular body 2 to contract and expand.

In fact, the body 2 is formed in a "natural" position (as shown in Figures 1 and 2) in which an outer wall portion 5 overlaps an inner wall portion 4.

Cross wires 6 of strong galvanized wire are secured at the bottom of the tubular body 2. They pass through apertures in the wall of the body 2 and have bent ends by means of which they are retained in place. It will be appreciated that they restrict expansion of the tubular body 2 at the bottom thereof, but in the absence of the ring 3, the tubular body 2 is still free to expand, above the wires 6.

An octagonal plate 7 rests on the cross wires 6, and serves as a closure member to the bottom of the body 2. However, it is to be appreciated that gaps 8 are left between the octagonal plate 7 and the substantially circular body 2.

When the plant pot 1 is empty, the ring 3 is an easy sliding fit over the tubular body 2. It can easily be fitted on to and removed from the tubular body 2.

However, there is provided a further body which is almost identical to the tubular body 2, but is not provided with the cross wires 6 and the octagonal plate 7. The purpose of this further body is to fit around the tubular body 2 when full, until it abuts the ring 3. Then, force may be transmitted to the ring 3 via the further body, to cause it to slide along the tubular body 2.

Use of the illustrated plant pot 1 will now be described in somewhat more detail.

Firstly, the plant pot 1 is assembled as illustrated in Figures 1 and 2 - namely, with the wires 6, bottom plate 7, and constraining ring 3 positioned approximately centrally. A soft compost is then placed into the plant pot 1 , and a Dahlia plant is then planted in the compost.

Thereafter, the plant pot 1 complete with its Dahlia plant and compost, is planted to the ground. Preferably, the plant pot 1 projects a little above ground level, to protect the crown of the tuber when grown.

The tuber is then left to grow, and is watered normally, as would be a Dahlia plant planted in open ground. It is to be appreciated that the holes 8 at the bottom the pot 1 allow feeding roots of the tuber to grow quite freely, and absorb moisture and nutrients from the soil, much in the same way as a tuber grown in open ground. The tuber grows quite rapidly, and soon fills the plant pot 1. This is the point at which a normal plastic or clay plant pot would break. However, as the growing season continues, the tuber continues to fill almost every availabie space within the plant pot 1, inside which there develops a considerable pressure. However, this pressure is readily withstood by the relatively strong material of the tubular body 2 and, in particular, by the presence of the constraining ring 3.

During the growing season, flowers may be cut as desired from the plant. The tuber grows in a very compact manner, under the great pressure within the plant pot 1, and thus is, in effect, a very "large" tuber in a small pot (i.e. it is very dense).

The tuber may thus provide a good abundance of flowers.

At the end of the growing season, the flower stems are trimmed off at the neck, and, as mentioned above, the height of the plant pot 1 above the ground continues to protect the crown of the plant, between the tuber and the neck.

Because the plant pot 1 has contained the tuber, and has allowed only feeding roots to grow out through the holes 8 and the bottom of the pot, the plant pot 1 complete with tuber may readily be lifted from the ground. This can be done by hand or, due to the regular nature in which a plurality of tubers may be grown, the harvesting of the tubers lends itself more readily to mechanisation.

Once the tubers have been lifted in their pots, they can be left therein for almost as long as is required. As the tubers are contained within the pots 1 under great pressure, they do not tend to dry out so quickly.

However, for most purposes, it is desired to remove the tubers from the plant pots 1, either for storage or for sale. Due to the great pressure prevailing within the plant pot 1, it is in most cases virtually impossibie to remove the constraining ring 3 readily by hand. Thus, at this stage, the further body that is mentioned earlier is placed around the tubular body 2 until it abuts the ring 3. Then, a sharp blow is applied to the top of the further body. The force is transmitted to the ring 3, which is then knocked downwardly towards the wires 6, allowing the upper regions of the tubular body to expand. Thereupon, the tuber may simply be lifted out of the plant pot 1.

It will thus be appreciated that tubers can be grown in great quantities, to a substantially standard size and shape. This makes them appear much more attractive for sale. Moreover, they are much easier to store, being very compact and of uniform shape. The tubers are very easy to dip when they have been lifted, e.g. for the purposes of applying insecticide, etc. The tubers are easily accessible for taking cuttings or for splitting. One particular interesting thing that has been noticed in experiments is that the tubers tend to be extremely resistant to fungal disease. This may be due to the great pressure under which they are grown, and/or due to their great degree of compactness, which greatly reduces the available area of attack for fungi.

The user of the plant pot 1 will very much appreciate the fact that, unless is has been subjected to very rough treatment, it will be re useable again and again. A new cutting may go straight into the plant pot 1 , where it will stay until grown to maturity. Use of the plant pot 1 may then be particularly advantageous where Dahlias are to be grown in poor ground, as each plant pot 1 may use good quality compost for each new cutting. As mentioned above, it is preferable to use a good quality soft compost in each pot 1, to avoid the presence of large grit, which could otherwise cause disfiguration of the tuber when it grows to fill the plant pot 1.

In experiments carried out in the United Kingdom, it has been found that the optimum length of the plant pot 1 is approximately fifteen centimetres. Growers wishing to take cuttings from a tuber will obtain them from the crown at the top of the tuber, so that there is nothing much to be gained by making the pots longer -- they will only be more difficult to lift, and will require more compost to fill. On the other hand, the pots do not want to be too short, as the tubers may then try to "escape" out of the bottom of the pot.

The experiments have also shown that the optimum diameter of the plant pots 1 is in the range seven to ten centimetres. If they are much narrower than this, there is generally not enough room for the tuber. They can be made wider, however, as a result of which larger tubers still will be obtained, with more crowns. This could be useful for a grower wishing to increase stock, by taking more cuttings, but for a grower wishing to sell single tubers, a diameter of pot in the range seven to ten centimetres is likely to be optimum.

Of course, it will be appreciated that these dimensions are appropriate to growing Dahlia tubers in the U.K. In other countries with differing climates, different dimensions may be more appropriate. It will also be appreciated that, although the illustrated example has been described with reference to the growing of Dahlia tubers, plant pots such as that illustrated may be used for growing any other plant, in which case dimensions may again be quite different.

Although the illustrated plant pot 1 has a tubular body 2 which is circular in cross-section, it will be appreciated that a plant pot in accordance with the invention may have any other desired shape of cross-section. For example, it may be thought that plant pots of square cross-section may yieid tubers of such a shape as to facilitate stacking even further, but on the other hand, more unusual shaped tubers might not be so attractive in appearance.

Claims

1. A plant pot comprising an expandable tubular body and a constraining member which passes around said body to constrain its expansion but is releasable so as to release such constraint.

2. A plant pot according to Claim 1 , wherein said body is cylindrical.

3. A plant pot as claimed in Claim 2, wherein said body is of circular cross-section.

4. A plant pot according to Claim 1, 2 or 3, wherein said body is elongate.

5. A plant pot according to any preceding claim, wherein said body is split from top to bottom, so as to be expandable.

6. A plant pot according to Claim 5, wherein said body has wall portions which overlap at said split.

7. A plant pot according to any preceding claim, wherein said constraining member is an annular member adapted to fit around said body, intermediate the top and bottom thereof.

8. A plant pot according to Claim 7, wherein said body and said constraining member have generally the same shape in cross-section.

9. A plant pot according to any preceding claim, wherein said body is open at top and bottom.

10. A plant pot according to any preceding claim, wherein the bottom of said body is partly closed by a closure member.

11. A plant pot according to Claim 10, wherein said closure member is in the form of a plate.

12. A plant pot according to Claim 1 1, wherein said body and plate have cross-sections one of which is circular and the other of which is polygonal.

13. A plant pot according to Claim 12, wherein said other cross-section is octagonal.

14. A plant pot according to any preceding claim, wherein wires cross the bottom of said body, and serve to restrict expansion thereof.

1 5. A plant pot according to Claim 14 appendant to any one of Claims 10 to 13, wherein said wires support said closure member.

16. A plant pot according to any preceding claim, wherein said body and/or said constraining member is/are of plastics.

1 7. A plant pot according to any preceding claim, wherein said body is formed of an extruded pipe, which i's cut to length and slit along its length.

18. A plant pot according to any preceding claim, wherein said constraining member is cut from a length of extruded pipe.

1 9. A plant pot according to any preceding claim, wherein the length of said body is substantially in the range 10 to 20 cm.

20. A plant pot according to Claim 19, wherein the length of said body is substantially in the range 14to 16cm.

21. A plant pot according to any preceding claim, wherein the diameter of said body is substantially in the range 5 to 1 5 cm.

22. A plant pot according to Claim 21, wherein the diameter of said body is substantially in the range 7 to 10 cm.

23. A plant pot according to any preceding claim, including a further body similar to the firstmentioned body and adapted to fit therearound to abut the constraining member such that a force may be transmitted to the constraining member via the further body, to dislodge the constraining member from around the first-mentioned body.

24. A plant pot substantially as hereinbefore described with reference to the accompanying drawings.

25. A method of growing a tuber, comprising the steps of planting the tuber of a plant in a plant pot according to any preceding claim, allowing the tuber to grow until it is constrained within the plant pot under pressure, subsequently releasing the constraining member around the body of the plant pot, and removing the tuber from the plant pot.

26. A method according to Claim 25, wherein the tuber is the tuber of a Dahlia.

27. A method according to Claim 25 and substantially as hereinbefore described with reference to the accompanying drawings.