JunkyardHydro - a Modular Ebb and Flow DIY Hydroponics System

Hello! I reside in Canada and in this instructable I will be showing you how to convert junk materials and appliances/objects in disuse into a modular ebb and flow hydroponics system. I recently got interested in hydroponics as well as other self-sustaining systems, so I decided to create one out of waste materials. I will also be outlining 2 methods in order to create the water delivery system to make this hydroponic setup work. One simply uses a water pump or a small fish tank filter, while the other design uses an air pump in conjunction with a large water bottle. I opted to go with using an actual water pump/filter method for the final system, but I also explain how to make a water pump using an air pump as well.

A hydroponics system is used to grow and water plants without the need for soil, resulting in a more compact setup with a decreased risk for the spread of soil-based diseases.

I aimed at not needing to buy any new materials for this project as I wanted to use both garbage and under-utilized appliances/objects to create the hydroponics system. I also want to show how anybody has the potential to use what is considered as waste/useless to create something that is much more useful. This is important since reducing humanities waste output one of the key elements essential to pave a way for a more sustainable future for generations to come. Furthermore, the fact that this project is modular means you can construct it in any order you want, constructing all the necessary components then combining them together at the end.

Materials needed to re-create this project are:

-water pump, air pump, or a small fish tank filter

-air pump tubing (if you are using an air pump instead)

-fish tank substrate cleaner tubing

-2 large water bottles or a plastic tub/bin

-a aluminum takeout-box (any box should do, but it will need to be waterproof or waterproofed)

-throw-away cups (paper or plastic ones will do)

-clay balls, wood chips, or any other inert growing media

-hot glue gun + glue sticks or any other adhesive/sealant

-a custom or interval outlet timer

There are a multitude of different hydroponic systems that are widely used, such being the Nutrient Film Technique (NFT), Wick Systems, Ebb and Flow, Deep Water Culture, Drip Systems, and Aeroponics. A brief description of how each works is included below, with an attached picture including visual depictions of each system as well.

Nutrient Film Technique:

This hydroponics system involves a shallow, sloped channel system where a thin film of nutrient-rich water continuously flows over the plant roots, providing essential nutrients while allowing oxygen exchange.

Wick Systems:

Wick systems in hydroponics use a passive method where a wick transports nutrient solution from a reservoir to the plant's root zone, ensuring continuous moisture and nutrient supply without the need for pumps or electricity.

Ebb and Flow / Flood and Drain:

This is a hydroponic method where plants' roots are periodically flooded with nutrient solution and then allowed to drain, promoting nutrient uptake and oxygenation.

Deep Water Culture:

The Deep Water Culture system is a hydroponic setup where plants are suspended in a nutrient solution with their roots submerged.

Drip Systems:

Drip systems involve delivering nutrient-rich water directly to the plant's root zone through a network of tubes and emitters.

Aeroponics:

Aeroponics is a method that involves suspending plant roots in air and misting them with a nutrient solution.

In all, it is important that the roots still have enough exposure to oxygen.

Source: https://www.nosoilsolutions.com/6-different-types-hydroponic-systems/

In this instructable, I will be using the ebb and flow system, since it will be the most viable method to create with the materials on hand, while also being extremely effective at delivering nutrients to the plants. An ebb and flow hydroponics system is a popular method of soilless plant cultivation. It consists of a growing bed or container filled with an inert growing medium (nutrition-less) where the plants' roots are placed. The system operates by intermittently flooding the growing bed with a nutrient-rich solution and then allowing all of it to drain back into a reservoir. The cycle's frequency typically ranges from a few times a day to once every few hours, depending on factors like plant type, growth stage, and environmental conditions. If you have a custom timer, you can set the flood session for about 2-5 minutes, but with an interval timer, just set it to one interval long. A benefit of the ebb and flow system is that the drainage tube allows for the water draining back into the reservoir to be oxygenated without the need for an additional air pump/stone.

Diagram Credit: https://www.backyardgardenlover.com/ebb-and-flow-hydroponic-system/

Before actually putting the waste materials to use, proper cleaning and preparation is needed in order to ensure the maximum vitality of the plants in the hydroponics system. In this case, I had used some soap and water to clean the aluminum takeout box and cups to rid it of any leftover grease, oil or leftover drink. If you want, you can also soak it with some heavily diluted bleach solution in order to help deter algae growth in the future as well. Simply rinsing the other materials with water should be sufficient enough to clean them. However, if you notice algae growth on the tubing, feel free to clean those with highly diluted bleach solution as well.

This step is only for those who want to make this system using an air pump. The design of this pump included using a 1.5L water bottle (any large soda bottle would do) in order to act as the reservoir for my system. A tube will be connected from the bottle to the aluminum box to allow for the delivery of water. The air pump will also be connected to the bottle via another tube as well, the delivery of air into the bottle will displace water out of the bottle through the tube connecting to the aluminum box via the cap of the bottle. This is demonstrated in the video provided.

Start by drilling out a hole on the cap of the bottle that is slightly smaller than the diameter of the fish tank cleaner tube. This will allow for a better airtight connection without the need for large amounts of additional sealant/glue. Slide the fish tank cleaner tube through the cap of the bottle until the end is about 1 cm from the bottom of the bottle. Drill another hole near the top of the bottle on its side way with a diameter that is once again slightly smaller than that or the air pump tube. Slide the air pump tube through the hole so that about 1 cm of it sticks into the bottle.

Next, drill a hole that is slightly smaller than the tank cleaner's tube on the bottom of the aluminum takeout box. Connect the cleaner tube from the water bottle to the side of the box and add extra glue/sealant as needed to ensure there are no leaks. Make sure the entrance of the tube is aligned with the bottom of the box, with no extra tube protruding into the takeout box.

If you happen to have a water pump, then just connect the tank cleaner tube to the spout of the pump, drill a hole that is slightly smaller than the tube on the bottom of the takeout box, and connect the tube to that hole using hot glue or sealant. Make sure the entrance of the tube is aligned with the bottom of the box, with no extra tube protruding into the takeout box.

I also discovered through some experimenting that you can also utilize some types of small fish tank filters in replacement of a water pump as well. In this case, that is exactly what I did. Since I did not want to spend extra money on purchasing a water pump, I decided to use an old small fish tank filter that is not in use. The model that I used is a Topfin WF200 bought for less than $10 CAD that has a maximum water delivery rate of 97.75 gallons/hour. However, I do recommend purchasing a water pump if you can, since the ones on the cheaper end are comparable in price and can have a faster water delivery rate in some cases.

Six circles where traced out on the cover of the aluminum takeout box in order for the cups containing the plants to be placed in. The diameter of the circles needed to be drawn were measured at a point about halfway down the cup (this is marked on the cup with a line in the picture). Ideally, you want to cut the whole wide enough so that the length of the cup protruding below the raft is about 2-3 cm above the base of the takeout box, and this happens to be halfway down the cup for me.

In this case I traced out 6 circles but feel free to trace out as many as you like, as long as space allows. Afterwards, scissors were used to cut out the circles, and the cups were placed in each of them to test the fitting.

Now that you ensured that the holes in the raft can properly accommodate the cups, multiple holes were drilled at the bottom of the cups to allow for the plants roots to grow through, as well as to let water flow in and out to provide the plants roots with water. However, make sure that the holes that you drill or cut out are not so large such that the filler placed in the cup to hold the plant in place will fall out through those holes.

Drill a second hole on the bottom of the aluminum takeout box slightly smaller than the width of the fish tank cleaner tube. Insert the fish tank cleaner tube to the takeout box and make sure it either feeds back to your water reservoir, or another bottle if you are opting to use an air pump instead. Furthermore, make sure that the height of the tube protruding into the base of the takeout box is about 1-2 cm below the top of the takeout box (or where the raft will be).

If using an air pump, make sure the secondary drain bottle is set up identically to your reservoir bottle (Step 4), as this will allow you to easily switch the bottle between flooding sessions instead of having to re-fill the reservoir bottle every time. Follow the same steps to connect the tube to the takeout box as described above.

It is also important to keep in mind that the drain tube has to be as big or larger than the flood tube so that the water entering the system does not overtake the rate at which it drains. When the cycle ends (when the water pump turns off), the rest of the water below the overflow tube line will drain through the backflow to the water pump, or to the initial reservoir bottle through the backflow of air through the air pump. It is important that the water fully drains from the takeout box to allow the plant's roots to have adequate exposure to oxygen. The "ribbed" bottom surface of the takeout box should also help with preventing small pools of water remaining at the bottom of the takeout box as well.

For the reservoir, an old bin was used to hold the water that will be circulated throughout the system. If the bin you are using is clear, make sure to paint or cover it to prevent excessive light from shining in, since that can result in algae growth. Drill 2 holes on the lid of the bin in the same spots that the tubes connected to the takeout box will be when the takeout box is placed on the bin's lid. Next, feed the tubes through each of the holes, and ensure the takeout box is level on the bin's lid. In the video provided, it shows the water draining through the overflow tube back into the reservoir. The fact that the water drains out of the tube above the water level in the reservoir allows the returning water to be aerated, eliminating the need for an additional air stone to aerate the water.

If using an air pump, you have already created your reservoir in the previous step(s)!

Before you start introducing the plants to the system, it is important to test the system for any leaks. Run the system through at least 1 complete cycle, letting it fill up fully then completely drain, while at the same time checking if there is water leaking through any of the connection points between the tubes and the aluminum takeout box. This step is important as you do not want to discover a leakage after you have already introduced the plants into the system.

Since the plants are being grown in an inert growing medium, you will need to mix a water-soluble (preferably) fertilizer/nutrient solution into the water in order to provide the plants with the essential nutrients they need to grow. In my case, I used the Miracle-Grow water-soluble all purpose plant food to mix with the water. Since the bin has a volume of 10 gallons, and I was filling it up to the halfway mark (5 gallons), I would need about 73 ml of fertilizer or about 3 and 1/3 big spoons of it (as per the instructions on the fertilizer label). After adding the required amount of fertilizer, mix the water-fertilizer mixture thoroughly to ensure that all the fertilizer dissolves in the water.

Remove pre-existing plants that you have from the current soil that they are in, and gently rinse away the soil with a hose. Try to use the mist or flat setting if you have a hose nozzle attachment, as you want to try to limit the agitation and damage to the plant's existing root system.

Place the plants stem in the middle of the cup and pour your filler (clay balls, wood chips, etc.) and make sure it is compact enough to secure the plant in place. Ensure that a decent portion of the plant roots are sticking through the holes at the bottom of the cup. If that is not possible, then ensure that the roots are near the bottom of the cup so that water from the flooding cycle will actually reach the plant's roots.

After you have created all the necessary parts for the hydroponics system, you can put it all together. Insert the cups with the plants into the lid, put the lid on the takeout box, then put the lid of the reservoir bin on top of the reservoir and ensure that the water pump is activated (if you just have 2 bottles, you can place the takeout box between 2 elevated surfaces). I recommend watching the hydroponics system through at least 1 full cycle to ensure that the water drains properly, as you do not want to come back to a surprise mess of water all over your floor!

In terms of daily monitoring, check your plants for any bug or pest infestations, as well as the pH levels. pH levels should be in between 5.5-6.5 for hydroponics, and you can test them using electronic or strip testers. Here is a link to a relatively cheap electronic pH tester as well, pH tester. You can also find electronic testers for TDS (total dissolved solids) and EC (electrical conductivity) as well if you want to monitor those too. Make sure to do some research on the proper level of all these measurements for the types of plants you are growing.

Depending on your reservoir size, you might need to completely change or top-up your nutrient solution every 1-2 weeks. You can also adjust the amount of nutrients, as young plants require lower nutrient concentrations than mature ones. You can also check for fungal or algae growth when changing your water, and scrub/clean any you find off the system.

You can also check your water temperature as needed as well, noting that the ideal water temperature for hydroponics is generally from 65°F and 75°F or 18°C to 24°C. Pruning your plants is important as well to ensure that they can all receive adequate light, as well as getting rid of any dead plant material.

Lastly, you can also consider completely flushing your entire system once in a while to prevent excess nutrient build up. Make sure to also periodically check your system for wear and tear, and replace or repair parts as needed.

And with that, you have your ebb and flow hydroponics system made from waste materials! I hope you enjoyed reading this instructable and hope you can benefit from this system if you have re-created it. Feel free to share with me your own modifications or suggestions on this system as well.