🌼 Dispenser for Sowing Tiny Seeds 🌼

🌼 Since childhood, I have always been amazed and inspired by the incredible power of nature to adapt and renew itself! You can admire how a huge plant grows from a tiny seed! Then, in childhood, everything seemed larger. Maybe because I was so small!)

In search of easier work when working with small seeds, the idea was born to create a manual universal seeder. Such a device allows you to sow a metered amount of seeds at a time. Using different nozzles, the area of its use increases, starting with very small seeds from 0.1 mm to several millimetres. This means that it will be possible to sow different plants. Starting with ornamental plants and flowers for the home and ending with garden crops. The dispenser will greatly help those who have greenhouses and are engaged in sowing small seeds in special module trays.

This seed pen can be loaded with seeds in advance and sent to the field to plant them. In the nozzles of which it consists, you can store different varieties of seeds and connect them as needed. Thus, based on this design, it can be supplemented with other prefixes. And given that it consists of very simple details that can be found in any home, its repetition will not be difficult. Of course, you can sow in “old-fashioned” ways, but after you try out this homemade product, there will be no turning back.

An important factor in the use of a dispenser is the dosed consumption of planting material. Considering that small seeds are sold in limited quantities and are expensive, their overspending during sowing is undesirable.

💡 This tool can also be used for in vitro propagation.

Materials

✿ pen d = 9.8-10 mm

✿ disposable syringe = 2 ml/5 ml

✿ an empty ink chamber pen (cartridge) d = 2.7 mm

✿ drill d = 1.3-1.5 mm (or more)

✿ spring d = 6.4 mm (6...10 mm)

✿ plastic sleeve (cap) d = 9.7…10 mm

✿ electrical tape or scotch tape

✿ a cap under the nose of the syringe (optional)

✿ module trays for plants (optional)

✿ propagation substrate/soil (optional)

✿ seeds: tobacco (Nicotiana tabacum)

Tools

✿ heat gun (building hair dryer)

✿ electric burner or soldering iron

✿ pliers (narrow)

✿ sandpaper

✿ caliper

✿ scissors

✿ stationery or assembly knife, and other workshop tools

The principle of operation of a stick pen was taken as the basis of this design. Incredible invention of mankind!) The automatic pen for writing has a mechanism for feeding the stick (ink chamber) into the working position, that is, by pulling outward, outside the barrel of the device.

So, when the button is pressed, the mechanism rotates forward, and due to sliding, the stick does not rotate. When pressed again under spring pressure, the stick moves along the guide to its original position. A thrust device, or cam, controls the extension or retraction of the cartridge.

These key pieces are on the top of the device, so you won't need the bottom of the pen (the nose cone).

The idea of creating a dispenser for sowing small seeds was inspired by the mechanism of a fountain pen, as well as another significant detail. We are talking about a part that allows you to push the seeds out of the device in a metered amount. The most suitable tool for this action turned out to be a metal drill with a diameter of 1.3 mm (1.5 mm). Typically, these drills are used to drill small holes in printed circuit boards for electronics. This part will work on the principle of a screw.

💡 You can use an old, dull drill bit. A new drill needs to be sanded so that the sharp edges do not damage the seeds.

In the case of working with larger seeds, you can also use either a metal drill with a larger diameter or find a suitable plastic screw in the form of an auger from various mechanisms and devices (CD-ROM). If you find a plastic one, the seeds will not be squeezed during the translational movements of the mechanism. But it is only suitable for large plant seeds.

In the case of working with small seeds, such as seeds of tobacco or flowering plants, a drill is most suitable for these purposes. Its diameter is inversely proportional to the size of the seeds. Considering the fact that tobacco seeds are very small, with the forward movement of the mechanism, they slip into the grooves of the drill and come out through inertia and gravity.

Based on these ideas, I began to experiment with creating a dispenser. At first, I tried to make a device with only a pen. By adding a piece of the tube to the tip of the pen and fixing the drill on the cartridge, I was able to check the overall performance of this mechanism. But, due to the inconvenience of placing seeds in the barrel of a pen as well as the small volume of the chamber, the dispenser required improvement. First, it was necessary to find a container (tube) that would fit more seeds. Secondly, due to the small diameter of the pen spring, the seeds got stuck and could be damaged when passing through it. Thirdly, small seeds could freely pass into the upper part of the barrel, and this would subsequently lead to incorrect operation of the mechanism.

Given the possible problems, I came up with the idea to use a body from an ordinary medical syringe with a volume of between 2 and 5 ml as a container. To assemble the tool, we also need a spring. It can be found in various toys or mechanisms.

💡 The diameter of the spring must be smaller than the diameter of the syringe!

So, having prepared all the components for the manufacture of the dispenser, you can begin to assemble it. The first step is to remove the ink from the cartridge. This can be done with a variety of solvents, such as alcohol, acetone, gasoline, or something similar. In my case, the cartridge turned out to be empty and dry.

Next, a drill with a diameter of 1.3–1.5 mm (or another diameter) is used. The total length of the drill was about 40 mm. In order to easily insert and fix the drill into a polyethylene tube, it needs to be slightly warmed up with a lighter or a building hair dryer.

Another important point: on the standard ink chamber, there are two fasteners (petals) that are designed to keep the spring in its workplace. In order to fix the spring with a larger diameter, it needs to be flattened a little with tweezers or pliers. This operation must be done when you heat the rod and place a metal drill in it.

Further, having prepared a spring of a suitable diameter (6.4 mm), it must be compressed with pliers to the diameter of the pen shaft, approximately 2.7–3 mm. After that, we thread the spring into the prepared ink chamber and fix it all the way, as seen in the photo. The total length of the finished rod with the drill is about 103 mm.

For further steps in the manufacture of the dispenser, a syringe is used that is suitable for the diameter of a pen. The barrel of the pen has an outer diameter of 9.8 mm. While the inner diameter of the syringe is about 9.3 mm.

In order to put these parts together, the plastic body of the syringe must be heated with a building hair dryer. It is desirable that the hair dryer have a temperature control for the supply of hot air.

💡 The syringe can also be heated on the fire of a gas stove or alcohol burner.

After a slight heating, the plastic body of the syringe will become soft, and at this moment, the barrel of the pen must be gently pushed into the body of the syringe, approximately 18 mm. Not strong, rotational movements need to stretch the container a little before it hardens.

After these operations, we proceed to the manufacture of a plastic sleeve. It will serve as a retaining ring in the barrel of the pen. You can do without it, but in this case, when the dispensary is turned over, small seeds will fall into the inside of the upper mechanism.

For further work, you first need to pull out the plastic threaded sleeve, which is located in the barrel of the pen and serves to fasten the lower cylinder (tip). Unfortunately, its inner diameter is larger than the diameter of the ink chamber. Therefore, it does not fit.

So, having picked up a sleeve that was suitable for the inner diameter, I had to slightly adapt it to the inner diameter of the barrel. The easiest way to process it is to melt it with a burner or soldering iron.

Having placed the sleeve on the awl, using a burner (you can use a soldering iron), I removed the excess plastic. In order to give it its final shape, it can be touched up with sandpaper. After that, it remains to insert the finished sleeve into the barrel of the pen. The sleeve should sit tight so that it does not fall out of the cylinder.

After all these preparatory operations, we already have a kit for assembling a dispenser for planting seeds. But, in order to give this seeder greater versatility, I thought to equip it with the ability to change cartridges, that is, pick up syringes of different diameters. The 5 ml syringe has a diameter of approximately 12 mm.

In order for it to fit into a planter with a smaller diameter, it will be necessary to add a spacer ring or a rubber tube of a suitable diameter. For these purposes, I adapted a rubberized tube from other stationery fountain pens. But, due to the fact that its diameter did not slightly coincide with the diameter of the syringe, I had to wind a small strip of electrical tape.

As a result, I got a universal device that can be put on different syringes by simply moving the tube up or down relative to the body.

So, there remains a minimum number of parts that need to be put together. And in order to store seeds in the dispenser case, you need to find some kind of plug so that they do not fall out. I found such a plug in my workshop. It is made of soft rubber, so it fits easily into the tip of the syringe.

💡 Such a tip can be made yourself from silicone.

Additionally, you can lubricate the elements of the pen mechanism with silicone grease. This will improve the performance of the device.

This tool will save you time and give you great pleasure when you work with it. It is ideal for sowing dry, small seeds that do not need to be pre-soaked. These seeds are sown in containers and module trays. The difficulty of sowing small seeds, such as seeds of tobacco, strawberries, arugula (rocket), petunias, primrose, sorrel, orchids, and celery, lies in the fact that it is difficult to distribute them without thickening. I have had experience with plants in past years, and I know the consequences of such seeding.

The tobacco seeds I have worked with are so tiny that they can easily be blown away with just one breath. Their diameter is approximately 0.1-0.15 mm. Rustic tobacco seeds are slightly larger: about 0.4–0.5 mm. Seeds must be handled very carefully! I used a small aluminium foil funnel to fill the dispenser cartridge. If you change from one variety of seeds to another, it is better to disinfect the tool!

💡 Alcohol or hydrogen peroxide can be used for disinfection.

After assembling the device for sowing seeds, it remains to be tested. For sowing, I prepared plastic food containers and module trays for plants, which I divided into four parts. For this, plastic wrappers from under the files were useful, which I had previously cut into a part that fit the size. To allow better passage of moisture, holes are made in them with a soldering iron. Also, holes were made in the bottom so that water would drain into the bottom pan. Thus, several varieties can be sown in such a container at the same time.

💡 It's also possible to use biodegradable module trays to plant directly in the garden.

Ready-made propagation substrate for seedlings or flowers is poured into containers. Such substrate can be prepared yourself. Taking garden soil, peat, and sand as a basis, in a proportion of three equal parts. After that, the soil must be decontaminated with boiling water or kept in the oven for about an hour at a temperature of about 100 °C (212 °F). It can also be sterilised in the microwave.

In cassettes for seedlings, using a dispenser, seeds can be dosed into each well individually. Even if several seeds are sown at the same time, in the future, extra seedlings can be removed (thinned out). Considering that the germination of different seeds differs depending on the variety and the duration of storage.

As a result, I was very satisfied with the work of the dispenser for sowing small and tiny seeds, and thanks to it, I saved time and effort and also avoided the effect of crowding seedlings.

Such a seed dispenser is a great tool for all those who are engaged in growing seedlings. I will be very glad to hear the feedback of those who make this device themselves and share their experience of using it!

Thanks for your time and attention to this topic! 🌼

P.S. Additional videos for this and other projects can be viewed on my YouTube channel (see my profile).