Initial Phase
Sketches and modelling
Overall structure
The overall supporting structure of our hydroponics unit is made of aluminium profiles. Our main focus for design and innovation comes from the growing frames and our biggest challenge is the automation of the dosing system.
We would test whether a stronger LED light or a weaker grow light would work better. This needs to be tested as the stronger white light may have better results than the weaker but specialised light for plant growth.
The reservoir holds the water pump that helps circulate the water through the troughs. The dosing system for regulating the ph and nutrient levels of the water would also be under the troughs and connected to the reservoir.
We decided to use several separate troughs instead of a tray setup that is commonly adopted when using the Nutrient Film Technology method. This is because we wanted to ensure that there would be better circulation of nutrient water to the roots as it reduces nutrient pooling and stagnation. Additionally, the frames would be easier to mount to the sides of the trough with this design.
The initial frame was inspired by netting and how the roots of the seedlings would be able to grow through it without growing into it so that the frame would be easily reusable.
The latest frame design takes into account different seed sizes as well.
LECA balls are a common substrate to germinate seeds and terracotta pots (olla pots) were used for water irrigation systems in the past. This terracotta frame was designed with that as the inspiration so that we would be able to wick the water up to the seeds to ensure that there is constant hydration.
These are the front and back caps of the troughs. The front cap would have two pipes for the inflow of the nutrient water while the slotted back cap would facilitate the return of the water to the reservoir so as to maintain the water level in the trough.
Prototyping
First frame prototype
This grid pattern and dimension allowed for even seeding and spacing of the seeds.
However, the holes were slightly too big to accommodate the smaller seeds such as arugula seeds. Approximately half of the seeds fall through the frame.
Moreover, we noticed that the first frame (left) was too shallow hence there was a need to constantly supply small amounts of water to ensure the seeds do not dry out especially during germination.
Second frame prototype
The second frame (right) was higher which allowed for water to collect below it which reduced the number of times we needed to replenish the water.
This frame was also resized to ensure even the smallest seeds do not fall through.
However, when we placed it into a shallow dish of water, the seeds proceeded to clump up due to mucilage during the seed imbibition period (means that the seeds swell up with water) as the top layer grid was too small to efficiently separate the seeds.
Third frame prototype
To solve the issue the first two prototypes were facing, this frame consists of a smaller bottom grid and a larger top grid so that seed sowing is still easy and the seed density can be maintained.
Even for a larger amount of the smaller types of seeds can be evenly and quickly sowed by gently shaking the frame. The the seeds fit very well in this frame and no seeds fell through.
Using the same train of thought, we are expanding on the types of frames to better accommodate seeds of different sizes and shapes.
These are the frames with their caps to facilitate the blackout and the tightness of the cap puts pressure on the seeds for the weighing down period.