JP7765009B2 - How to grow onions - Google Patents

Description

Article 30, Paragraph 2 of the Patent Act applies. (1) Announced at "SAGA Lab 10+G" held at the Saga Prefectural Government Office on October 8, 2021. (2) Published on page 18 of the Saga Shimbun morning edition on October 9, 2021.

The present invention relates to a method for cultivating small onions known in Japan as "pekoros."

In Japan, small onions with a diameter of about 3 to 4 cm are called "pekorosu." Although these onions are the same variety as regular onions, they are sweeter than regular onions and, due to their smaller outer diameter, are often served whole in a variety of dishes. Non-Patent Document 1, described below, discloses the following method for cultivating pekorosu in intermediate or warm regions of Japan.

That is, in September, seeds are sown in nursery beds, which are used for raising seedlings, and the seedlings are germinated and raised. Then, around late October or November, the grown seedlings are dug up from the nursery beds and planted in the actual field. When planting, while regular onions are planted 10-15cm apart, pearl onions are planted 3-5cm apart, and the seedlings are planted overcrowded, suppressing bulb growth. The planted seedlings take root and become established, but stop growing in winter, only to resume growth in spring. They are harvested from mid-April onwards, when bulbs of an appropriate size have been obtained.

As mentioned above, there is demand for these types of pecoros, but due to the low domestic production volume, they have a high market value and are traded at a high unit price.

"How to Grow and Cultivate Vegetables: How to Grow and Cultivate Pecoros," [online], [Retrieved February 1, 2022], Internet <https://xn--m9jp4402bdtwxkd8n0a.net/howto/pecoros>

However, with this conventional cultivation method, both seedling raising and planting are carried out in the field, and the planting process cannot be mechanized, so the spacing between planted seedlings is uneven, and therefore the size of the harvested pearl peas is also uneven, resulting in a low yield of pearl peas of the required size that meets the standard. Furthermore, because the tasks of digging up seedlings from the seedbed and planting the resulting seedlings in the field cannot be mechanized, these tasks must be done by hand, requiring excessive labor.

The present invention was made in consideration of these circumstances, and provides a method for cultivating onions that can increase the yield of pearl onions of the desired size and minimize the amount of cultivation labor required.

(1) The onion cultivation method of the present invention is a method for cultivating onions having a bulb diameter of 40 mm or less by sowing onion seeds in a suitable culture medium, characterized in that the culture medium is filled into each cell of a cell tray having a suitable number of cells, and the seeds are sown in the culture medium of each cell, followed by germination, growth, and harvesting.

In the onion cultivation method of the present invention, onion seeds are sown in an appropriate culture medium to cultivate onions with bulb diameters of 40 mm or less. The culture medium is then filled into each cell of a cell tray having an appropriate number of cells. Onion seeds are then sown in the culture medium of each cell, followed by germination, growth, and harvesting. Because the process from sowing to harvesting is carried out using cell trays in this way, there is no need for digging up and planting, as in conventional cultivation methods, and cultivation labor and work time can be significantly reduced. Furthermore, by using cell trays having an appropriate number of cells, the yield of small onions with bulb diameters of 40 mm or less can be improved.

(2) Furthermore, the onion cultivation method of the present invention is characterized in that the cell trays used have a cell capacity of 15 ml or more and 40 ml or less, and the distance between the centers of adjacent cells is 25 mm or more and 54 mm or less.

In the onion cultivation method of the present invention, cell trays are used in which the capacity of each cell is 15 ml or more and 40 ml or less, and the distance between the centers of adjacent cells is 25 mm or more and 54 mm or less.

If the cell volume is less than 15 ml, the harvested onions cannot be grown to the required size, resulting in an extremely low yield of standard-sized onions. On the other hand, if the cell volume exceeds 40 ml, the onions will grow too large, resulting in a low yield of standard-sized onions. In contrast, if the cell volume is between 15 ml and 40 ml, the onions can be grown to the required size, resulting in the greatest possible yield of standard-sized onions.

The distance between the centers of adjacent cells in the cell tray is preferably 25 mm or more and 54 mm or less, and more preferably 35 mm or more and 41 mm or less. If the distance between the centers of adjacent cells constituting the cell tray is less than 25 mm, sunlight is blocked by the influence of the leaves of adjacent seedlings, which inhibits the growth of the harvested onions and therefore makes it difficult to improve the yield of onions of the specified size. If the distance between the centers of adjacent cells exceeds 54 mm, the planting density becomes too low, reducing the yield of onions per unit area and making it difficult to improve the yield of onions of the specified size. In contrast, if the distance between the centers of adjacent cells is 25 mm or more and 54 mm or less, the influence of the leaves of adjacent seedlings can be minimized while an appropriate planting density can be achieved, thereby improving the yield of onions of the specified size.

(3) Furthermore, the onion cultivation method according to the present invention is characterized in that the seeds are sown in the culture medium filled in each cell between late January and early February in Japan.

In the onion cultivation method according to the present invention, seeds are sown in the culture medium filled in each cell between late January and early February in Japan. If seeds are sown before mid-January, the cultivation period becomes longer, which increases the likelihood of onions becoming infected with disease and increases cultivation costs. On the other hand, if seeds are sown after mid-February, the cultivation period from sowing to harvest is shorter, which results in smaller harvested onions and a lower yield of onions of the specified size.

In contrast, if the sowing time is between late January and early February, the cultivation period is appropriate, so the onions are less likely to become infected with disease and the yield of onions of the specified size is high. Furthermore, it is possible to prevent an increase in cultivation costs.

(4) The onion cultivation method according to the present invention is also characterized in that the cell trays are separated from the field during the cultivation period.

In the onion cultivation method of the present invention, the cell trays are separated from the field during the cultivation period. Separation can be achieved by placing the cell trays on a table, or by placing an impermeable sheet or the like between the field and the cell trays.

This prevents the onion seedling roots from being affected by the field soil as they grow within each cell, resulting in more uniform size harvested onions.

1 is a flowchart illustrating, in chronological order, an example of a method for cultivating onions according to the present invention.

The onion cultivation method according to the present invention will be described in detail with reference to the drawings.
The onion cultivation method described in this embodiment is an example for explaining the gist of the present invention, and it goes without saying that the present invention includes modifications and alterations within the scope of the gist of the present invention.

Figure 1 is a flowchart illustrating a chronological example of an onion cultivation method according to the present invention.

In the cultivation method of the present invention, when cultivating the small onion variety Pecora, the entire process from sowing and growing to harvesting is carried out using cell trays, which are made up of small pots called cells connected in a grid pattern. Before sowing, the worker prepares for cultivation by selecting the appropriate cell tray and filling each cell of the selected cell tray with culture soil, as follows (Step S1).

The cell tray used should preferably have a capacity of 15 ml to 40 ml per cell, and more preferably 24 ml to 30 ml.

If the cell volume is less than 15 ml, the pearls cannot be grown to the required size, resulting in an extremely low yield of pearls of the specified size. On the other hand, if the cell volume exceeds 40 ml, the pearls will grow too large, resulting in a low yield of pearls of the specified size. In contrast, if the cell volume is between 15 ml and 40 ml, the pearls can be grown to the required size, resulting in the highest possible yield of pearls of the specified size.

Furthermore, the distance between the centers of adjacent cells in the cell tray is preferably 25 mm or more and 54 mm or less, and more preferably 35 mm or more and 41 mm or less. An example of an existing cell tray that meets these conditions is the Yanmar Napla Vegetable Tray with 128 holes (manufactured by Yanmar Holdings Co., Ltd.).

If the distance between the centers of adjacent cells making up the cell tray is less than 25 mm, the leaves of adjacent seedlings will block sunlight, inhibiting the growth of pearl syrup and preventing the yield of pearl syrup of the specified size from increasing. Furthermore, if the distance between the centers of adjacent cells exceeds 54 mm, the cultivation density will be too low, reducing the yield of pearl syrup per unit area and preventing the yield of pearl syrup of the specified size from increasing. In contrast, if the distance between the centers of adjacent cells is between 25 mm and 54 mm, the influence of the leaves of adjacent seedlings can be minimized while allowing for an appropriate cultivation density, thereby improving the yield of pearl syrup of the specified size.

Rice padding for cell-molded seedlings can be used as the culture medium (cultivation medium) for cultivating pearl stalks. Cell-molded seedling culture medium is prepared by mixing soil with peat moss and vermiculite to have chemical and physical properties suitable for producing high-quality seedlings with excellent growth, such as rooting and attachment, and for managing seedlings. It is suitable for cultivating pearl stalks using cell trays. Various types of seedling culture medium for cell-molded seedlings are commercially available, but one example that can be used is Yosaku N-150 (manufactured by Kyushu Chemical Industry Co., Ltd.).

Fertilizers used to grow pearl onions can be used, such as Micro Long Total 280 100-day type (sold by JCAM Agri Co., Ltd.).

The amount of fertilizer added to the cultivation medium should be adjusted so that the amount of nitrogen added is approximately 900 mg per 1 L of cultivation medium. For example, if using Micro Long Total 280, 100-day type, add approximately 281 g per 45 L of cultivation medium.

For example, approximately 281g of Micro Long Total 280 100-day type is added to 45L of cultivation soil, and this is then filled into each cell of, for example, a Yanmar Napla vegetable tray with 128 holes (manufactured by Yanmar Holdings Co., Ltd.).

In this embodiment, an example using an existing cell tray has been described, but the present invention is not limited to this, and it goes without saying that a dedicated cell tray can be applied in which the inner diameter and depth of each cell, the capacity of each cell, and the distance between the centers of adjacent cells have been optimally adjusted.

Once preparations for cultivating pearl onions are complete in this way, the worker sows onion seeds in each cell of the cell tray (step S2), and then separates the cell tray from the field soil by, for example, placing the cell tray on a platform of appropriate height (step S3).

This allows the cell trays to be kept separated from the field soil, preventing water from splashing back onto the seedlings when water is sprayed onto the cell trays, reducing the risk of disease. Furthermore, as the seedling roots grow within each cell, they are protected from the influence of the field soil, resulting in more uniform size harvested pearls.

If you do not use a mounting table, it is a good idea to place a suitable sheet between the cell tray and the soil surface in the field that is impermeable to moisture and nutrients. In this case, the sheet will also prevent water from splashing back onto the seedlings from the soil surface inside the greenhouse when watered, reducing the risk of disease while also preventing any impact from the field soil.

The onion varieties suitable for cultivating pearl onions are early, very early, or super-very early varieties. If mid- or late-season varieties are used, the pearl onions will not swell as quickly, making it difficult to obtain pearl onions of the required size. Early varieties include Charm, Kaizuka Wase, and Wase No. 7. Ultra-early varieties include Hamawarai and Takanishiki. Ultra-early varieties include Super Kogane, for example.

The onion cultivation method of the present invention can be applied to regions in Japan where autumn-sown onions are produced, such as Kyushu, Chugoku, Shikoku, Kinki, Chubu, and Kanto regions. However, by introducing active temperature control equipment that uses energy, such as heating and heat retention or cooling and heat retention in greenhouses, the method can also be applied to regions at higher or lower latitudes.

In areas where autumn onions are grown, the sowing period should be between late January and early February, and more preferably early February. If the sowing period is before mid-January, the cultivation period will be longer, which increases the likelihood of onions becoming infected with disease and increases cultivation costs.

On the other hand, if the sowing time is after mid-February, the cultivation period from sowing to harvest is short, resulting in smaller pearls and a lower yield of pearls of the specified size.

In contrast, if the sowing time is between late January and early February, the cultivation period is appropriate, so the onions are less likely to become infected with disease and the yield of standard-sized onions is high. Furthermore, it is possible to prevent an increase in cultivation costs. Also, sowing in early February is more preferable, as it allows for the maximum yield of standard-sized pearl onions to be achieved.

In this specification, the period from the 1st to the 10th of each month is referred to as the first half, the period from the 11th to the 20th as the middle, and the period from the 21st to the last day of the month as the last.

At this time, since the temperature in the field is not yet suitable for germination and growth at the aforementioned production location and sowing time, the seeds are grown in a greenhouse (Step S4). For example, cell trays are placed inside a greenhouse made of an appropriate material such as vinyl or glass, and when the temperature inside the greenhouse reaches approximately 22°C to 24°C, both sides of the greenhouse are opened to ventilate the greenhouse, thereby controlling the temperature inside the greenhouse.

Here, temperature control involves adjusting the temperature from sowing to germination to an average range of approximately 10°C to 25°C, and from germination to harvest to an average range of approximately 15°C to 27°C. Therefore, in areas where such temperatures can be guaranteed in the open field, greenhouse cultivation is not necessary.

Germination is inhibited whether the temperature from sowing to germination is below about 10°C on average or above about 25°C on average. Furthermore, if the temperature from germination to harvest is below about 15°C on average, the growth of buds, leaves, bulbs, and roots is inhibited by the low temperature, and if the temperature exceeds about 27°C on average, growth is inhibited by the high temperature.

In addition, while cultivating the pearl stalks, the worker waters each cell tray as needed to prevent the soil in each tray from drying out (step S5).

For example, for about one month after sowing, water the plants once a day using a sprinkler or similar device to provide 100 to 150 ml of water per cell tray, and then continue watering twice a day as before. In the latter case, watering should be reduced to once a day if it rains.

Since the harvest season for pearl peas is approximately one week after the leaves have fallen over, the worker determines whether the pearl peas have reached harvest time based on whether the leaves have fallen over (Step S6), and repeats Steps S4 and S5 until it is determined that the pearl peas are ready for harvest.

If the worker determines in step S6 that the pearls have reached harvest time, they harvest the pearls from each cell in the cell tray (step S7). The worker then measures the diameter of the harvested pearls (step S8) and, based on the measurement results, sorts the pearls by size (step S9) to obtain pearls of the specified size.

In this way, the onion cultivation method of the present invention uses cell trays to carry out the entire process from sowing to harvesting, eliminating the need for digging up and planting, as is required with conventional cultivation methods, and significantly reducing cultivation labor and work time. Furthermore, by using cell trays with cells of appropriate capacity and an appropriate distance between the centers of adjacent cells, it is possible to easily increase the yield of pearl onions of the desired size. Furthermore, in Japan, the cultivation period is as short as possible, from late January to mid-June at the longest.

On the other hand, because the plants are grown using cell trays without using a field, there is no problem with continuous cropping when cultivating pearl stalks. Also, because the plants are grown separated from the soil in the field, the occurrence of disease can be avoided as much as possible.

As mentioned above, the regions in Japan where the onion cultivation method of the present invention can be applied are Kyushu, Chugoku, Shikoku, Kinki, Chubu, Tokai, and Kanto regions, as well as the surrounding areas. However, it goes without saying that the method of the present invention can also be applied to other regions, such as overseas countries, as long as they have similar weather conditions. In this case, since the progression of the seasons is reversed in the northern and southern hemispheres, the number of months from sowing to harvesting must be adjusted accordingly.

Next, the results of carrying out the onion cultivation method according to the present invention will be described.
Example 1
In this example, the results of examining the effect of differences in the size of the cells that make up the cell tray on the size and yield of harvested pearl barley are described.

Table 1 below shows the results of an investigation into the effect that differences in the capacity of the cells that make up the cell tray have on the size of the harvested pearl stalks, and Table 2 shows the results of an investigation into the effect that this has on the yield of the pearl stalks.

The following cell trays were used: 72-hole cell trays, 128-hole cell trays, 200-hole cell trays, and 288-hole cell trays (all Yanmar Napla vegetable trays; manufactured by Yanmar Holdings Co., Ltd.), and a 448-hole cell tray (Minoru Pot 448-hole; manufactured by Minoru Sangyo Co., Ltd.). The cell volume of each cell tray was 38.0 ml for the 72-hole cell tray, 27.0 ml for the 128-hole cell tray, 16.0 ml for the 200-hole cell tray, 11.5 ml for the 288-hole cell tray, and 4.0 ml for the 448-hole cell tray.

Yosaku N-150 (Kyushu Chemical Industry Co., Ltd.) was used as the cultivation medium, and approximately 281g of Micro Long Total 280 100-day type fertilizer (sold by JCAM Agri Co., Ltd.) was added per 45L of cultivation medium.

This culture soil was filled into each cell of the cell tray, and on February 3, 2021, one Charm seed was sown in each cell of each cell tray. Cultivation then began by placing each cell tray on a platform installed in a greenhouse at the Saga Prefecture Uebata Agricultural Center, and pearl peas were harvested from each cell tray on June 6, 2021.

When the temperature inside the greenhouse reached approximately 24°C, both sides of the greenhouse were opened and the greenhouse was ventilated to adjust the temperature inside the greenhouse so that it remained within a range of approximately 15°C to 20°C on average from sowing to germination, and approximately 15°C to 27°C on average from germination to harvest. For approximately one month after sowing, the seeds were watered once a day using a sprinkler to provide 100 to 150 ml of water per cell tray, and thereafter, the same watering was carried out twice a day. In the latter case, watering was reduced to once a day on rainy days.

In Table 1, M indicates a diameter of 36.1mm to 40.0mm, S indicates a diameter of 33.1mm to 36.0mm, 2S indicates a diameter of 30.1mm to 33.0mm, and 3S indicates a diameter of 25.1mm to 30.0mm. Furthermore, "products" refer to peaches with diameters between 3S and M; peaches with diameters less than 3S and those with diameters exceeding M are not considered products.

As is clear from Table 1, the diameter of the harvested pearls increased as the cell volume increased. Furthermore, when using a 448-hole cell tray, i.e., when the cell volume was 4.0 ml, it was not possible to harvest pearls with a diameter of 3S or larger. Furthermore, when using a 72-hole cell tray, i.e., when the cell volume was 38.0 ml, the percentage of pearls harvested with a diameter exceeding M exceeded 30%.

On the other hand, as is clear from Table 2, with 72-hole cell trays to 200-hole cell trays, i.e., with cell capacities ranging from 38.0 ml to 16.0 ml, a product yield of over 1,000 g was obtained per tray, but with 288-hole cell trays, i.e., with cell capacities of 11.5 ml or less, a product yield of less than 400 g per tray could only be obtained.

Based on the above results and our experience growing pearl peas, it is preferable that the capacity of each cell be between 15 ml and 40 ml. It is even more preferable that the capacity of each cell be between 24 ml and 30 ml.

As mentioned above, if the cell volume is 11.5 ml or less, the product yield will be less than 400 g per tray, and therefore, based on experience, it is believed that if the cell volume is less than 15 ml, the yield of standard-sized pearl onions will be extremely low.

On the other hand, since the percentage of harvested cells with diameters exceeding M exceeded 30% when the cell volume was 40 ml, it was determined that the upper limit of the cell volume was 40 ml.

As is clear from Tables 1 and 2, when using a 128-hole cell tray, i.e., when the cell volume was 27.0 ml, the harvest rate of M diameter was highest and the product yield was also the highest. Therefore, it was considered more preferable for the cell volume to be around 27.0 ml, i.e., a cell volume of 24 ml to 30 ml.

Example 2
Next, we will explain the results of an investigation into the effect that differences in the distance between the centers of adjacent cells have on the diameter of the harvested pearl syrup.

Table 2 also shows the results of an investigation into the effect that differences in the distance between the centers of adjacent cells that make up the cell tray have on the diameter of the harvested pearl syrup. Table 3 also shows the results of a further investigation into the effect that differences in the distance between the centers of adjacent cells have on the diameter of the harvested pearl syrup.

For each of the cell trays mentioned above, the distance between the centers of adjacent cells is as follows: 50.0 mm for the 72-hole cell tray, 38.0 mm for the 128-hole cell tray, 28.0 mm minimum for the 200-hole cell tray, 23.0 mm minimum for the 288-hole cell tray, and 19.0 mm minimum for the 448-hole cell tray.

Table 3 also shows the results of examining the effects on the diameter of harvested pearls when seeds are sown in all 128 wells and in 32 of the 128 wells of a 128-well cell tray, when seeds are sown in 60 of the 200 wells of a 200-well cell tray, and when seeds are sown in 66 of the 448 wells of a 448-well cell tray. The distance between the centers of adjacent cells is 70.0 mm when seeds are sown in 32 wells of a 128-well cell tray, 57 mm when seeds are sown in 60 wells of a 200-well cell tray, and a minimum of 54 mm when seeds are sown in 66 wells of a 448-well cell tray.

Note that, except for the sowing date being January 29, 2020, and the harvest date being June 10, 2020, the variety, soil, fertilizer, temperature control, and watering management were the same as above.

As is clear from Table 3, when comparing a 128-well cell tray where seeds were sown in all 128 wells with a tray where seeds were sown in 32 of the 128 wells, the longer the distance between the centers of adjacent cells, the heavier the average bulb mass. Also, when comparing a 448-well cell tray where seeds were sown in all 448 wells (Table 2) with a tray where seeds were sown in 66 of the 448 wells (Table 3), the longer the distance between the centers of adjacent cells, the higher the yield. This is thought to be because as the distance between the centers of adjacent cells increases, the influence of the leaves of adjacent seedlings on adjacent seedlings is reduced, preventing sunlight from being blocked, promoting the growth of the pearl stalks.

However, as is clear from the results of comparing the case where seeds are sown in all 128 wells of a 128-well cell tray with the case where seeds are sown in 32 of the 128 wells, if the distance between the centers of adjacent cells is made longer than necessary, the cultivation density will become sparse, resulting in a reduction in product yield per tray.

On the other hand, as is clear from Table 2, when 288-hole cell trays were used, i.e., when the distance between the centers of adjacent cells was a minimum of 23.0 mm, the product yield per tray did not reach 400 g, whereas when 200-hole cell trays were used, i.e., when the distance between the centers of adjacent cells was a minimum of 28.0 mm, the product yield per tray exceeded 1,000 g.

Based on these results and our experience growing pearl syrup, we believe that the distance between the centers of adjacent cells should be at least 25 mm.

In contrast, when a 128-hole cell tray was used, i.e., when the distance between the centers of adjacent cells was 38.0 mm, the product yield per tray exceeded 1,900 g. Furthermore, when a 72-hole cell tray was used, i.e., when the distance between the centers of adjacent cells was 50.0 mm, the product yield per tray was maintained at 1,000 g or more. Additionally, a comparison of a 448-hole cell tray in which seeds were sown in all 448 wells was made with a comparison of a case in which seeds were sown in 66 of the 448 wells. In the latter case, when the distance between the centers of adjacent cells was a minimum of 54 mm, the product yield increased, suggesting that the distance between the centers of adjacent cells should be 54 mm or less.

Furthermore, as is clear from Tables 2 and 3, when using 128-hole cell trays, i.e., when the distance between the centers of adjacent cells is 38.0 mm, the product yield per tray is highest. Based on experience growing pearl peas, it is considered more preferable that the distance between the centers of adjacent cells be between 35 mm and 41 mm.

As mentioned above, if the distance between the centers of adjacent cells making up the cell tray is less than 25 mm, the leaves of adjacent seedlings will block sunlight, inhibiting the growth of pearl syrup and preventing the yield of pearl syrup of the specified size from increasing. Furthermore, if the distance between the centers of adjacent cells exceeds 54 mm, the cultivation density will be too low, reducing the yield of pearl syrup per unit area and preventing the yield of pearl syrup of the specified size from increasing. In contrast, if the distance between the centers of adjacent cells is between 25 mm and 54 mm, the influence of the leaves of adjacent seedlings can be minimized while still allowing for an appropriate cultivation density, thereby improving the yield of pearl syrup of the specified size.

Example 3
Next, we will explain the results of an investigation into the effect that differences in the holding environment of the cell tray have on the diameter of the harvested pearl stalks.

Table 4 below shows the results of an investigation into the effect that differences in the cell tray holding environment have on the diameter of harvested pearl peas. Six 128-hole cell trays and six 200-hole cell trays were used as cell trays, which were divided into two groups: one group was placed on a stand placed inside the greenhouse, and the other group was placed directly on the field (groundbed) inside the greenhouse. The sowing and harvest dates, variety, soil, fertilizer, temperature control, and watering control were all the same as in Example 1.

As is clear from Table 4, whether using a 128-hole cell tray or a 200-hole cell tray, there was greater variation in the diameter of the harvested pearl peas, and a higher proportion of pearl peas with a diameter of less than 3S, when the cell tray was placed directly on the field and kept in an environment not separated from the field, compared to when the cell tray was placed on a table and kept in an environment separated from the field.

This is thought to be because the roots of seedlings growing within each cell of the cell tray extend out through the small holes at the bottom of the cell, come into contact with the field soil, and are affected by the field soil.

Therefore, when cultivating pearl barley, it is preferable to place the cell tray on a stand, for example, and maintain it in an environment separated from the field.

Example 4
Furthermore, we will explain the results of an investigation into the effect of differences in sowing time on the diameter of harvested pearl stalks.

Tables 5 and 6 below show the results of an investigation into the effect of different sowing times on the diameter of harvested pearl stalks. 128-hole and 200-hole cell trays were used, and these were divided into three groups. Group 1 was sown on January 23rd, Group 2 on February 3rd, and Group 3 on February 23rd. The other factors, including variety, soil, fertilizer, temperature control, and watering control, were the same as in Example 1.

As is clear from Table 5, when 128-hole cell trays were used, the market yield was relatively high regardless of the sowing time, but as is clear from Table 6, when the sowing time was in late February, the size of the harvested pearls was smaller than when other sowing times were used. Furthermore, when 200-hole cell trays were used and the sowing time was in late February, not only were the harvested pearls smaller in size than when other sowing times were used, but the proportion of market yield to total yield was also extremely low.

Based on these results, it appears that the best time to sow seeds is between late January and early February, with early February being more preferable.

Example 5
We will also explain the results of an investigation into the effect of different onion varieties on the diameter of harvested pearl onions.

Table 7 below shows the results of an investigation into the effect of different onion varieties on the diameter of harvested pearl onions. The onion varieties used were Charm, Kaizukawase, and Wase No. 7 as early varieties, Hamawarai and Takanishiki as very early varieties, and Super Kogane as an extra-very early variety. Tarzan was also used as a mid-season variety. The soil, fertilizer, temperature control, and watering management were the same as in Example 1, except that 128-hole cell trays were used and seeds were sown in early February.

As is clear from Table 7, the commercial yield of mid-season varieties was extremely low compared to the early, very early, and super-very early varieties. In contrast, the commercial yield of early, very early, and super-very early varieties was high, at around 1,000g per cell tray.

Based on these results, it appears that early, very early, and super-extra early varieties are preferable for onion varieties.

Step S1 Preparation for cultivation Step S2 Sowing Step S4 Growing Step S5 Water supply management Step S9 Sorting

Claims (4)

A method for cultivating onions having a bulb diameter of 40 mm or less by sowing onion seeds in a suitable culture medium, comprising:
Filling each cell of a cell tray having a suitable number of cells with the culture medium,
A method for cultivating onions, comprising sowing the seeds in the culture medium of each cell, followed by germination, growth and harvesting. The onion cultivation method according to claim 1, wherein the cell trays are those in which the capacity of each cell is 15 ml or more and 40 ml or less, and the distance between the centers of adjacent cells is 25 mm or more and 54 mm or less. The method for cultivating onions according to claim 1 or 2, wherein the seeds are sown in the culture medium filled in each cell between late January and early February in Japan. 4. The method for cultivating onions according to claim 1, wherein the cell trays are separated from the field during the cultivation period.