Net cup angles in vertical hydroponics are little details that I missed back when I was a beginner. I thought, “Nah, this won’t affect my garden so much!” But I was wrong—some of my hydroponic plants were softening and drying out. That’s when I realize I’m using the incorrect net cup angle.
In general, the best net cup angle for vertical hydroponics is 45 degrees for hydroponic towers and 90 degrees for vertical nutrient film technique. With these angles, nutrient loss and pooling of nutrient solution in the net cup are avoided. This also prevents algae bloom and salt buildup in the system.
Why is net cup angling so important in vertical hydroponics? What will you gain from using the optimal angles? Learn the “whys” and hurry to your vertical hydroponic system to adjust your net cups if you are using the wrong one.
The optimal angle of net cups for vertical hydroponics depends on the system type. The best net cup angle for hydroponic towers is 45 degrees, while the best net cup angle for nutrient film technique is 90 degrees.
By using these angles for a specific vertical hydroponic system, the hydroponic solution can efficiently touch the roots of the hydroponic plants to supply the needed nutrients.
You may have noticed that two different systems were mentioned above. This is because the best angle is determined by the type of vertical hydroponics used by the gardener. For you to have more knowledge about this, proceed to the next section.
Vertical hydroponics transports nutrient-rich water towards the upper portion of the system using a water pump. The nutrient water, with the natural pull of gravity, rains down from the top and is collected at the bottom for recirculation.
This system, unlike other hydroponic systems, saves space since the orientation of the system is upwards. Thus, this is perfect for indoor gardens that are located in your own kitchen!
Considering this feature, there is a need for a high-pressure water pump to deliver the water to the top of the system.
Another interesting fact about vertical hydroponics is its wide scope of advantages, including:
- The system can harvest a greater amount of plants per unit area.
- Ideal for small sunny areas such as balconies, patios, and rooftops.
- It enables year-round indoor production.
- It can frequently provide more than 90% water efficiency.
- There are no soil-borne pathogens.
In the following section, I will go over the two most common types of vertical hydroponics: nutrient film technique and hydroponic towers.
Two of the most common vertical hydroponic systems are nutrient film technique and hydroponic towers. These types of vertical hydroponics use different net cup angles for maximum efficiency.
In the nutrient film technique vertical hydroponics, the tubes are stacked on top of one another and linked using elbow pipes. The stream flows down from an upper channel to the channel beneath it, and so on. The hydroponic nutrient solution is then recirculated.
- Hydroponic nutrient reservoir
- Hydroponic nutrients
- Submersible water pump
- Water hose (link from the water pump to the top tube)
- Growing tubes
- Net cups (must be angled 90 degrees, upright angle)
- LED grow lights with timer
Compare other systems in our article on horizontal vs vertical NFT.
In hydroponic towers, the water flows the same way as in the nutrient film technique. The only difference is that the water rains down on the roots after reaching the top. This is contrary to the nutrient film technique where the water flows downward passing through a tube.
Here is an illustration I created to help you understand the system better.
- Tower body (can be made from PVC pipe or metal)
- Top perforated reservoir (where the nutrient solution goes before it rains down to roots)
- Nutrient water reservoir
- Submersible water pump
- LED grow lights with timer
- Water hose (linked from the water pump to the top)
- Net cups (must be angled 45 degrees)
Positioning the net cup at the proper angle will prevent drying out of roots and pooling of nutrient solution. Otherwise, these can lead to algae formation and/or salt buildup, and nutrient loss due to splashing and leaking.
To help you visualize the possible problems caused by wrong angling, let us use the illustration below. For the next subsections, we will refer to the scenarios in this illustration as:
- Scenario A for wrong net cup angling (45°) in vertical nutrient film technique (NFT)
- Scenario B for wrong net cup angling (90°) in hydroponic tower
These scenarios, as you may have realized, are the inverse of the optimal net cup angles for each vertical hydroponic system.
Using the proper angle of net cups will prevent drying out of roots, especially in hydroponic towers, because it will make sure that the roots are receiving the water and nutrients from the top reservoir.
This will be an effect of scenario B, where the net cups are angled at 9 degrees instead of 45 degrees.
In the illustration above, an upright angle was used for a hydroponic tower. The consequence of this mistake is having a plant’s roots dry out.
Remember that in hydroponic towers, the nutrient water rains down. So if you angle the net cup in an upright position, then the hydroponic solution will not reach the roots of your plants since they are hanging downwards.
Now, where will the hydroponic solution go in this scenario? Two answers:
- It will just flow down to the reservoir again without touching the roots; or
- It will go directly into the net cup.
This can further result in the pooling of the nutrient solution.
Pooling of nutrient solution in the net cup may cause further problems such as algae formation and salt buildup. This results from improper angling of net cups in a hydroponic tower.
When the nutrient solution rains down, in scenario B, the possibility is that it will accumulate inside the net cup.
Because the net cup is exposed to light, coupled with the abundance of water and nutrients, algae growth is inevitable.
Algae can grow on the surface of the growing medium, competing with the nutrients supplied to the hydroponic plants.
When nutrient solution accumulates in a growing medium that is heated by lighting, there is a high likelihood of salt build-up over time.
You may be wondering, where does this salt come from? They are from the hydroponic nutrients that you dissolved in your nutrient water. When exposed to too much heat, there is a higher rate of evaporation, which leaves the nutrient in the water behind.
Nutrient loss because of leaking and/or splashing is a common problem in vertical hydroponics. High water pressure from the water pump can cause nutrient water to leak and splash out of the tube and net cup if it is placed at the wrong angle.
If you have noticed, this consequence happens from a combination of poor net cup angle and high water pressure. In scenario A, the hole in the tube is angled at 45 degrees, instead of 90 degrees. This mistake will lead to leaking and/or splashing of nutrient solution.
Using the illustration above, what do you think will happen if the tube is filled with nutrient water halfway? If your answer is leakage, then you are correct! Leaks of nutrient solution in hydroponics are considered a waste of resources, so you need to watch out for them!
Leakage is also affected by high water pressure. When there is high pressure, the tubes are also filled faster.
When there is extreme water pressure, there is a high possibility of splashing when the pressure of water hits the net cup positioned at a 45-degree angle. The water may splash out from the net cups and be wasted as well.
Learn more about this in our article on water pressure in hydroponics.
Can the type of hydroponic pipes being used affect splashing and leaking?
Pipe types used in hydroponics, such as polyvinyl chloride (PVC) or metal, do not affect splashing and leaking, however, the pipe sizes will. If a high-pressure water pump is used, bigger pipes can control water splashing and leaking since it will take a longer time to fill them. By contrast, if a low-pressure water pump is used, smaller pipes can minimize leaking.
Does net cup size matter in hydroponic gardening?
Net cup size in hydroponics does matter. It is determined by the plant type and hydroponic system. For instance, small leafy vegetables and herbs grown in NFT need 2″ to 3″ diameter net cups, whereas tall vegetables need 4″ to 6″ net cup sizes in a deep water culture system. Learn more in our article net cup sizes in hydroponics.
What can I use instead of net cups for hydroponic systems?
Styrofoam cups and recycled plastic cups can be used instead of the ready-to-use net cups available in the market. However, these alternatives require slight modifications for them to be useful for hydroponics. Explore how to do it in our article DIY deep water culture hydroponics.
The best net cup angle for vertical nutrient film technique hydroponics is 90 degrees; while it is 45 degrees for hydroponic towers.
Angling in vertical hydroponics is essential to prevent drying out of roots, pooling of nutrient solution, and nutrient loss, which all have negative effects on the hydroponic plants.
- “Building a Vertical Hydroponic Tower” by Singh, H. and Dunn, B. in Oklahoma State University
- “State of the Art of Urban Smart Vertical Farming Automation System: Advanced Topologies, Issues and Recommendations” by Md Saad, M.H. et al. in Electronics
- “The vertical farm: controlled environment agriculture carried out in tall buildings would create greater food safety and security for large urban populations” by Dickson Despommier in Journal für Verbraucherschutz und Lebensmittelsicherheit
- “Understanding and Using NFT Hydroponic Systems’ by Lynette Morgan by Maximum Yield
- “Vertical farming increases lettuce yield per unit area compared to conventional horizontal hydroponics” by Touliatos et al in Food and Energy Security