WO1997000003A1

WO1997000003A1 - Seed germination and sowing

Info

Publication number: WO1997000003A1
Application number: PCT/GB1996/001410
Authority: WO
Inventors: Barnaby Miln
Original assignee: Barnaby Miln
Priority date: 1995-06-17
Filing date: 1996-06-17
Publication date: 1997-01-03
Also published as: AU6012296A; GB9512375D0

Abstract

Seeds (13) are individually spaced and arranged in pockets between a pair of sheets of flexible material of a growth medium (1). The seeds (13) are germinated with the growth medium (1) floating on water (30). The entire growth medium (1) can then be sown directly in soil, keeping the existing spacing of the seeds (13), or portions of the growth medium (1) can be separated for sowing.

Description

SEED GERMINATION AND SOWING

This invention relates to germination and sowing of seeds and to the provision of seeds in a form which is easy to handle.

Individual seeds, particularly those which are small in size, are difficult to handle. Seed sowing machines which use a row of hollow needles to automatically pick up individual seeds under suction and place them in individual compartments of a soil filled seed tray are used by nursery growers. Although such machines improve the ease of seed handling they are costly to install and operate and seeds are prone to bounce out of some of the individual compartments.

Alternatively, individual seeds are sometimes coated with a layer of clay to form a spherical pellet containing the seed which is far larger and far easier to handle than the uncoated seed.

It is also known to flame laminate randomly spaced grass seeds within two layers of foam to form a mat; the mat is then rolled out to alleviate the necessity of sowing individual seeds. The seeds are randomly arranged on the foam by means of a vibrating table.

According to a first aspect, the present invention provides a method of germinating a plurality of seeds as specified in Claim 25.

Seeds require moisture, an adequate temperature and oxygen to germinate. By floating the seeds on water the water is available to the seed at a rate controlled by- the seed's own requirement. Placing seeds on the growth medium individually at optimum spacing gives each seed the best possible opportunity to obtain water, oxygen and temperature without having to compete for these limited resources with other seeds sowed in too close a proximity. Germination can be impeded when seeds are completely surrounded by water because, whilst the seeds will absorb the water needed, the germination process cannot proceed until there is a supply of oxygen from the air. Unless oxygen is available soon after the absorption of water the seed will begin to rot.

The growth medium may be arranged to float in a tray of water; it is preferably arranged in an atmosphere where ambient temperature and/or humidity is controlled.

The growth medium may comprise a pair of sheets having the seeds entrapped between them; the sheets may be adhered together. The growth medium may comprise a plurality of individual pockets, each containing an individual seed, formed between the pair of sheets. The growth medium may be flexible. It may be made partly or wholly of a foam or foamed plastics material which may be a polyester and/or polyurethane foam.

The growth medium may float on or near the surface of the water; preferably, it floats just above the water. The growth medium may be hydrophillic. Preferably, the growth medium floats without requiring any separate form of buoyancy. A number of water trays, each having a respective growth medium floating at its surface may be stacked one above the other, for example, on a trolley. This may enable a large number of seeds to be germinated together in a controlled atmosphere of restricted volume. The depth of a water tray may be significantly less than the depth of a seed tray into which seeds would conventionally be sown along with soil for germination.

Once the seeds have germinated, the whole of the growth medium may be sown; the growth medium may be sown in the ground. Alternatively, the growth medium may be arranged on soil in a seed tray. The seed tray may have individual compartments and, in this case, the spacing of the seeds in the growth medium preferably corresponds to the spacing of the individual compartments.

Preferably, the growth medium is still sufficiently strong to be moved once germination has occurred. It may subsequently decompose once sown in soil.

According to a second aspect, the present invention provides a method of arranging a seed on a growth medium as specified in Claim 14.

The stream of fluid is preferably air and may be created by applying suction to an underside of the growth medium. According to a third aspect, the present invention provides a growth medium as specified in Claim 1.

According to a fourth aspect, the present invention provides a seed tray including a growth medium in accordance with Claim 1.

By use of the present invention, considerably fewer seeds may be required to produce a certain number of plants. Frequently, less than 10% of seeds sown in a garden grow into plants. Some of the factors inhibiting seed germination and growth include a shortage or over-supply of water, a shortage of oxygen, incorrect temperature, scavenging by birds and rodents, seeds being dropped too far into the soil, being blown away or being sowed too close to other seeds. Similar problems occur in agriculture; it is estimated that as little as 50% of cereal seeds and no more than 20% of small seeded grasses produce plants.

The present invention may also facilitate the spacing of seeds at their optimum distance apart.

Young seedlings are very fragile and can be damaged when pricked out for transplanting. The present invention allows them to be removed easily from the growth medium, for example, by lifting them off the water in which the seeds have been germinated and tearing them away or cutting round them with scissors. The growth medium may be perforated around the individual seeds to facilitate separation.

The present invention allows the seeds to be grown initially on water and may cut down the cost, bulk and mess associated with seed compost. It also cuts out the need to keep seed compost at the correct moisture level throughout the germination period.

Embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings of which:

Fig 1 is a perspective view, partially cut away, showing seeds being placed onto a growth medium; Fig 2 is an enlarged cross section of a concave plate of Fig 1; Fig 3 is a perspective view of an alternative form of concave plate; Fig 4 is a cross section of a partially finished growth medium; Fig 5 is a cross section showing sealing of individual pockets of the growth medium; Fig 6 is a perspective view showing a finished growth medium; and Fig 7 is a sectional side view of a growth medium floating on water in a water tray.

The apparatus 10 shown schematically in Fig 1 is used for individually placing a plurality of seeds from a seed trough 11 onto a first layer of polyurethane foam 12 which forms part of a growth medium. Individual seeds 13 are picked up from the seed trough 11 by suction applied to the inside of hollow needles 14 arranged in a row across the machine. The seeds are transferred by the needles 14 to the top of individual tubes 15 where the suction on the needles 14 is released and each individual seed falls down its respective tube 15 onto the growth medium 12. The needles 14 and tubes 15 are arranged across the width of the machine but, for convenience, only a small number are illustrated. The lower end of each tube 15 is arranged over a concave plate 16 which forms part of a base 17 over which the growth medium 12 is advanced.

The foam layer 12 is sufficiently flexible to follow the contour of the concave plate 16, as shown in Fig 2. The concave plate 16 has a number of orifices 18 which correspond in spacing to the tubes 15. Each orifice 18 is connected to a respective suction pipe 19 which draws an air stream through a portion of the growth medium 12. This suction encourages a seed 13 which has been dropped onto the growth medium 12 to assume a desired position and discourages the seed 13 from bouncing out of formation. In this way, each individual seed can be accurately placed onto the growth medium 12 at a desired spacing from adjacent seeds.

In an alternative form of concave plate 16, as illustrated in Fig 3, the plate 16 is divided into individual sectors 20 separated by barriers 21. Each sector 20 is concave to provide a form of dimple into which each individual seed is received.

In further alternative arrangements (not illustrated) the concave plate may have an elongated slit passing across the width of the machine to which suction is applied to facilitate placement of the seeds as opposed to individual orifices and tubes. In a yet further embodiment (not illustrated) the needles 14 may place the seeds 13 directly onto the growth medium 12 rather than dropping the seeds down tubes 15.

An adhesive may be used to stick each individual seed to the growth medium 12. This may be applied to each individual seed before it is placed on the medium; it may be applied to the seeds either individually or together once they have been placed onto the growth medium or it may be provided as a strip across the width of the growth medium at a position at which the seeds are to be placed.

Once a row of seeds has been placed onto the growth medium 12 the growth medium is advanced through the machine 10 for the next row of seeds to be placed thereon.

Optimum spacing between seeds is dependent upon seed type and variety. The machine may be configured to arrange to seeds at a set spacing across the width of the machine. It may be adjustable to allow an alternative spacing to be selected. It may possible to operate the machine using a limited number of the needles 14 at spaced intervals across the width of the machine (ie making some needles inoperative) to provide for a desired spacing of seeds.

Fig 4 shows a cross section of a growth medium comprising a bottom layer 12 onto which a plurality of seeds 13 have been placed and an upper layer 22 of polyurethane foam which has been placed on top of these. This may be done at the apparatus of Fig 1 once the seeds have been placed on the growth medium.

An annular heat source 23 is shown in Fig 5 being applied to the growth medium of Fig 4. The heat source 23 has a heated metal end 24 which is used to partially melt the foam layers 12 and 22 to provide a seal 25 around each individual seed 13. The seal 25 is created by adhering or partially adhering the first and second layers 12, 22 together. Alternatively, the seal may be created by means of an adhesive. The seal need not be continuous; its function is to create a pocket 26 between the layers of the growth medium in which the individual seed 13 is retained.

The heat source 13 may be provided by individual heaters, one per seed, or may be provided in the form of a bar passing across the width of the machine 10.

Fig 6 shows a completed growth medium in which portions of the upper layer 22 have been removed. The only portions of the upper layer 22 remaining at the growth medium are those parts 27 which form the upper cap of the individual pockets 26 retaining the individual seeds.

Fig 7 shows a completed growth medium 1 floating at the surface of water 30 in a tray 31. Once the seeds 13 are germinated, the growth medium 1 will be removed in its entirety and sown in soil. The seeds 13 are arranged at the growth medium at the optimum spacing for direct sowing in soil.

In an alternative arrangement, the growth medium 1 may be intended to be divided into a number of portions, each portion containing an individual germinated seed, and each portion sown in soil. The growth medium may be provided with perforation lines or lines of weakness to facilitate this. In this case, the seeds may be arranged more closely together in the growth medium than the optimum sowing spacing to maximise the number of seeds that can be germinated for a set area of growth medium.

The bottom layer 12 of the growth medium 1 may be thicker than the top layer 22. The bottom layer may provide support for plant shoots and plant roots may break through and grip into this layer. The top layer may be thinner to allow the shoots from the seeds to break through. The layers may be marked to facilitate identification of which is the top and which is the bottom layer. The layers may be coloured.

Granular moisture retainers may be incorporated in to the growth medium. This may add weight to the growth medium and may provide a water source for the seeds. The grains may be incorporated into one or more or of the layers of the growth medium and/or they may be held in the pockets between the sheets of the growth medium along with the seeds. Individual grains of moisture retainers may be placed on to the growth medium in a similar way to the seeds.

Examples of seeds which can be used with the present invention include alpine strawberries, ground cover, seeds for herb gardens, seeds for rock gardens, seeds for annual borders, mustard and cress, ornamental grasses, green foliage, soup pot vegetables, trees, lettuces, hanging basket flowers, game cover and field flowers.

Some examples embodying the present invention are given below:

1. Twenty four lettuce seeds (Lactuca sativa) were mechanically and evenly placed the recommended distance apart from each other onto the surface of a polyester urethane foam 1.25 mm thick which is the size of a standard seed tray (14" x 8"). A second sheet of polyester foam 1 mm thick and of the same size as the first was placed on top of the first. It had been rendered tacky by passing it through a gas flame at a temperature of 1150 °C and so bonded to the first. The resultant product was so strongly bonded that it was impossible to separate the laminated foam layers. The germination rate of the seed in the laminate was no different to that of seed from the same source sowed in seed compost and both germinated under similar conditions in a seed laboratory. 2. Example 1 was repeated except that ten petunia seeds (Petunia Solanaceae x hybrida) were similarly placed on a round sheet of polyester urethane foam with a diameter of 5.5" - the size of a typical plant pot saucer.

3. Fifty seeds of carrot (Daucus carota sativus), leek (Allium porrum) , swede (Brassica napus), radish (Raphanus sativus), cauliflower (Brassica oleracea) and parsnip (Pastinaca sativa) were each mechanically and evenly placed in rows the correct distance apart for each type of seed onto the surface of a polyester urethane foam 1.5 mm thick and the coated product was supplied continuously into the nip of a flame lamination machine. At this point the coated foam was contacted with a second polyester urethane foam 1.25 mm thick whose surface had been rendered tacky by passing it through a gas flame at a temperature of 1150 °C. To avoid damage to the seeds the gas burner was angled upwards at 30 °C to the horizontal. The resultant product was a length of laminated foam bonded so strongly that it was impossible to separate the layers and contained rows of the six vegetable seeds ready for germination. Tests in the seed laboratory showed a very satisfactory germination rate.

4. Fifty seeds of carrot (Daucus carota sativus). leek (Allium porrum), swede (Brassica napus), radish (Raphanus sativus), cauliflower (Brassica oleracea) and parsnip (Pastinaca sativa) were each mechanically and evenly placed in rows the correct distance apart for each type of seed onto the surface of a polyester urethane foam 1.5 mm thick. A second polyester urethane foam 1.25 mm thick whose surface had been sprayed or otherwise covered with an adhesive was firmly pressed on top of the first layer. The resultant product was a length of laminated foam bonded so strongly that it was impossible to separate the layers and contained rows of the six vegetable seeds ready for germination. Tests in the seed laboratory showed a very satisfactory germination rate.

5. Fifty seeds of carrot (Daucus carota sativus), leek (Allium porrum), swede (Brassica napus), radish (Raphanus sativus), cauliflower (Brassica oleracea) and parsnip (Pastinaca sativa) were each mechanically and evenly placed in rows the correct distance apart for each type of seed onto the surface of a polyester urethane foam 1.5 mm thick. A second polyester urethane foam 1.25 mm thick was placed on top and the sandwich fed into a stitching machine to bind the two layers together. The resultant product was a length of laminated foam bonded so as to contain rows of the six vegetables seeds ready for germination. Tests in the seed laboratory showed a very satisfactory germination rate.

6. Fifty crocus bulbs were each mechanically and evenly placed in a row the correct distance apart on a strip of polyester urethane foam 7 mm wide and 1.55 mm thick. At this point the coated foam was contacted with a second polyester urethane foam 1.25 mm thick whose surface had been rendered tacky by passing it through a gas flame at a temperature of 1150 °C. The resultant product was a length of laminated foam bonded so strongly that it was impossible to separate the layers and contained rows of crocus bulbs ready for imbibition of water to start the growth process.

7. Seeds were placed onto the surface of a layer of 1.25 mm thick polyester foam and a spray of a water soluble glue directly at each seed to fix it in place.

8. Seeds were placed onto the surface of a buoyant material and a spray of a water soluble glue directed at each seed to fix it in place.

9. Seeds were placed onto the surface of a buoyant material and a spray of a water soluble glue containing fungicide directed at each seed to fix it in place.

10. Seeds were placed onto the surface of a buoyant material and a spray of a water soluble glue containing fungicide and fertiliser directed at each seed to fix it in place.

11. Seeds were placed onto the surface of a buoyant material and a spray of a water soluble glue containing fungicide, weedkiller and fertiliser directed at each seed to fix it in place.

12. Seeds were placed onto the surface of a buoyant material and a spray of a water soluble glue containing fungicide, pesticide, weedkiller and fertiliser directed at each seed to fix it in place.

Claims

1. A growth medium comprising a pair of sheets of flexible material, adhered together and capable of floating on water and a plurality of non-randomly spaced seeds arranged between the sheets.

2. A growth medium in accordance with Claim 1, in which individual seeds are retained in individual pockets between the sheets of flexible material.

3. A growth medium in accordance with Claim 2, in which each individual pocket is formed by adhering the sheets together around a perimeter of an individual seed.

4. A growth medium in accordance with Claim 3, in which one of the sheets is non-continuous and comprises a plurality of spaced portions each of which forms part of an individual pocket.

5. A growth medium in accordance with any preceding Claim, in which a lower sheet of the pair is thicker than an upper sheet of the pair.

6. A growth medium in accordance with any preceding Claim, in which the pair of sheets comprises foam rubber.

7. A growth medium in accordance with any one of Claims 1 to 5, in which a lower sheet of the pair comprises foam and an upper sheet of the pair comprises a sheet of starch.

8. A growth medium in accordance with any preceding Claim, in which at least one of the sheets is hydrophillic.

9. A growth medium in accordance with any preceding Claim, in which the growth medium contains at least one of a fungicide, a pesticide, a fertiliser and a weedkiller.

10. A growth medium in accordance with any preceding Claim in which the growth medium is adapted to retain its initial integrity during germination and to subsequently decompose when sown in soil.

11-. A growth medium in accordance with any preceding Claim in which the growth medium contains a moisture retainer.

12. A growth medium in accordance with Claim 11 in which the moisture retainer is in the form of a pellet incorporated into the growth medium.

13. A growth medium in accordance with Claim 11 or Claim 12 in which the moisture retainer is a cross-linked polyacrylamide.

14. A method of arranging seeds at a growth medium comprising the steps of: a. creating a fluid stream through a portion of the growth medium; and b. placing a plurality of seeds non-randomly on the growth medium such that the fluid stream encourages each of the individual seeds to remain in the position in which it has been placed.

15. A method in accordance with Claim 14, in which the fluid stream is created by applying suction through the growth medium.

16. A method in accordance with Claim 14 or Claim 15, in which the growth medium is arranged to have a concave portion onto which each seed is placed.

17. A method in accordance with any one of Claims 14 to 16, in which the growth medium is flexible and is arranged over a concave plate to create the concave portion.

18. A method in accordance with any one of Claims 14 to 17, in which the seeds are placed on a first layer of growth medium and comprising the further step of: c. arranging a second layer of growth medium over the first layer to sandwich the seeds therebetween.

19. A method in accordance with Claim 18 comprising the further step of: d. adhering the first and second layers together around a perimeter of each individual seed to form an individual pocket in which the individual seed is held.

20. A method in accordance with Claim 19, in which the pocket is formed by local melting of at least one of the layers by application of a localised heat source to create a seal around the perimeter of the individual seed.

21. A method in accordance with Claim 19, in which the pocket is formed by use of an adhesive to create a seal around the perimeter of the individual seed.

22. A method in accordance with any one of Claims 19 to 21 comprising the further step of: e. removing portions of the second layer which do not form part of the pocket.

23. A method in accordance with any one of Claims 14 to 22 comprising the further step of: f• guillotining a side edge of the growth medium to seal that edge.

24. A method in accordance with any one of Claims 14 to 23, in which the growth medium is in accordance with any one of Claims 1 to 13.

25. A method of germinating a plurality of seeds, comprising the steps of: a. providing a growth medium of a sheet material within which a plurality of non-randomly spaced seeds are arranged; and b. arranging the growth medium such that it floats at the surface of water so as to promote germination of at least some of the seeds.

26. A method in accordance with Claim 25 in which the growth medium is buoyant and floats at the surface of the water without supplementary support.

27. A method in accordance with Claim 25 or Claim 26 comprising the further step σf: c. removing the growth medium from the water surface once at least some of the seeds have germinated and transferring the growth medium incorporating the seeds to soil to sow the seeds.

28. A method in accordance with Claim 27, in which the growth medium is transferred to the soil by placing the growth medium on a seed tray having a plurality of individual compartments, the spacing of the seeds in the growth medium corresponding to the spacing of the individual compartments so that there is a one to one correspondence between the seeds and the individual compartments over at least part of the seed tray.

29. A method in accordance with any one of Claims 25 to 28, in which the growth medium is in accordance with any one of Claims 1 to 13.

30. A seed tray including a growth medium in accordance with any one of Claims 1 to 13.

31. A growth medium substantially as described herein with reference to one or more of the accompanying drawings.

32. A method of germinating seeds substantially as described herein with reference to one or more of the accompanying drawings.

33. A method of arranging seeds at a growth medium substantially as described herein with reference to one or more of the accompanying drawings.