A Beginner’s Guide To Hydroponics
How to design, build and operate a small hydroponics farm [from an urban farmers who grows over 800 heads of lettuce a year]
I do not have a green thumb.
I have managed to kill the cactus in my room that I was told “is indestructible” (sorry Marge 🌵), and the pink Marigold I got from the tooth fairy when I was 11, nine days after I got it.
I always thought that when I grew up I’d be better at keeping plants alive. But now, at 16, I think that my gardening skills have actually decreased (if that’s even possible).
So it is saying a lot that I have become an urban farmer, and have been able to operate a small hydroponics farm with just under 100 heads of lettuce.
It has been a huge learning curve designing, creating and operating my hydroponics system, and I am excited to share with you my story and approach to go from 0 gardening knowledge to urban farmer. Welcome to my Beginner’s Guide To Hydroponically Growing Lettuce.
Depending on your needs and interests (e.g. if you want to learn about hydroponics farming, if you want to create your own hydroponics system, if you want to learn about my hydroponics farm) use this index to skip to the section that is most relevant to you ✨
Welcome to the first section of this guide: Designing, where I’ll walk through my process of designing my own hydroponics farm, provide advice to help you design yours and share links to products and resources I used.
Why hydroponics matters?
Hydroponics is a way of growing plants in water instead of soil. Nutrients are dissolved in the water, so plant roots have direct access to the nutrients they need.
Plants grown hydroponically use 90% less water than soil based agriculture, 99% less land, and the crazy thing to me, is that hydroponics produces 20 times larger yields per unit area than traditional agriculture!
You might be thinking, that’s cool, but why even bother? And the answer to this question is quite simple: we don’t have a choice.
The truth is that the way we are currently producing food SUCKS.
38% of global land is used to grow plants. One-third of this space is used to grow crops to feed humans, and the remaining two-thirds is used to either grow crops to feed animals, or grazing pastures for livestock. A whopping 67% of global freshwater is used to irrigate crops.
We are using up Earth’s most important resources (land and water) at an alarming rate, and still can’t feed everyone on the planet.
Close to 1 billion people on this planet live off $1 a day and don’t have enough to eat, while the Western world is throwing out hundreds of billions of pounds of food each year (we waste a third of the total amount of food produced globally). This doesn’t even touch on the environmental impact of agriculture — we are polluting the air, soil, water, and the planet in an outdated, broken food production system that produces 27% of global greenhouse gas emissions.
And our agricultural system is charged with an enormous task: by 2050, we will need to increase food production by 60% in order to meet the caloric needs of a global population of 9.8 billion people. If we were to project linear growth in yield from our agricultural output from the past five decades, we would be nowhere near achieving this kind of growth by 2050.
What I’m getting at here is that we need a better solution. We don’t have a choice.
A solution is hydroponics.
(Figuring out how to produce more food with less resources, with less land and in any climate.)
What is hydroponics + how does it work?
Hydroponics is a way of growing plants in nutrient water, instead of soil. The plant roots are completely submerged in water, instead of conventional farming where the roots are grown in soil.
Hydroponics is not nearly as complicated as it sounds. All that is needed is water, oxygen, root base, nutrients and light:
Water is the most important part of a hydroponics system. The entire system is built off water which hydrates the plants, and provides a home in which the plants can thrive.
Without oxygen, the plants will drown in the water. Plants grown hydroponically will absorb oxygen in the water (water is made up of 2 hydrogen molecules and one oxygen molecule, so water contains a lot of ‘hidden’ oxygen!), but need additional O2 which comes from an air pump which secretes and regulates the oxygen level inside the reservoir.
Root bases 🌱
The root base is a medium that protects and secures the roots, making sure the plant doesn’t drown. It can be peat moss, rock wool, clay pellets, rice hulls, and anything else that will give the roots some added support and protection.
In traditional farming, plants absorb hundreds of organic nutrients in the soil, and obtain their essential, non organic nutrients from fertilizer, which are sprayed on crops by the farmers. Water lacks most of these essential plant nutrients, so in hydroponics, a nutrient solution must be added to the water so the plants can absorb the nutrients from the roots. The three main nutrients plants need are nitrogen, phosphorous and potassium (NPK).
Light is a must to ensure photosynthesis takes place. Full spectrum LED lights provide a concentrated form of energy which is perfect for plant growth.
Plants grown hydroponically need a perfect balance of these 5 elements.
Let me paint a crystal clear picture of what hydroponics is: there are pipes or trays full of water with holes at the top which net cups sit in. As the plant grows, the roots drop into the water and absorb the nutrients. The lights shine on the plants for 12–16 hours a day and nutrients are added periodically throughout the week. Usually hydroponics farms are vertically stacked (like the picture below of Bowery Farms, the largest commercial vertical farming company) to optimize space.
And that is literally how simple hydroponics is.
You swap dirt for water, and sun for LED lights, and BOOM what you’re left with is hydroponics!
There are six different categories of hydroponic setups: deep water culture (DWC), drip system, nutrient film technique (NFT), ebb and flow, wick system, aeroponics.
Deep water culture
DWC is the simplest of all hydroponics setups. The plant roots are submerged in a deep bucket of water (at least 1.5 ft deep). This is much different from the other setups which use a minimal amount of water to conserve space.
In DWC the nutrients are added to the water and the air is provided directly to the roots with an air pump or air stone.
The versatility of DWC is what makes it so cool — it supports heavy plants like tomato, squash or zucchini which don’t grow well in other setups, and long root veggies like carrots and beats which can’t grow in any other setup.
Unlike DWC where the nutrients are added to the water, in drip systems, nutrients are pumped through a tube right to the base of the plant. At the end of the tube, a drip emitter controls how much nutrients are let out.
The great thing about this setup is that it can be tailored for each individual plant. If there is one plant that needs a lot of nutrients, but the plant beside it already has enough, the drip emitters can be adjusted to suit the needs of each individual plant, making it one of the most efficient hydroponics setups.
Drip systems can either be circulating or non-circulating. A circulating system drips at a slow, constant rate so that the plants get all the nutrients they need. Any excess nutrient water flows back into the reservoir and is circulated throughout the system again. The non-circulating system drips at a faster rate for brief periods of time, flooded the root bases every few hours with nutrient water, and then leaves the plants to absorb the nutrients.
Nutrient film technique
NFT systems have two components: a try which the plants sit in and a reservoir. The trays are at a slight angle, so that the water quickly drains through the trays and back into the reservoir. There is a small pump that circulates the water from the pump up to the trays.
Since only the very tips of the roots are getting wet, the water is very concentrated with nutrients so the plants get everything they need.
NFT is the most scalable of all setups and is used commercially to grow large amounts of plants.
Ebb and flow
The ebb and flow system is nicknamed “flood and drain” which is actually very accurate to how this system works. The plants are placed in a try called a grow bed which is filled with peat moss or clay pellets. The try is flooded with nutrient water from the reservoir bellow until the water level is just a few inches from overflowing. Then the pump shuts off, the water drains out of the bed and back into the reservoir.
This gives the plants time to soak up the nutrients and water before the pump floods the grow bed again, and the cycle continues.
The beauty of the wick system is that it is super simple (it doesn’t even need a pump!). The plants are grown above the reservoir in clay pellets. A nylon wick is strung between the plant base and the reservoir. As the wick absorbs the water and becomes damp, droplets of water reach the base of the plant and this is how the plant gets it’s water and nutrients!
Aeroponics technically is not hydroponics — it is a separate category of alternative growing. But I’m going to throw it into this list anyway.
Instead of being submerged in water, in aeroponics, plant roots are suspended in air, and a light mist of water and nutrients is sprayed on the roots. A cool feature of aeroponics is that it can (and many times is) designed to be grown in vertical pillars. Since the plant roots need to be spread out, vertically grown is a great way to save space.
Designing a system that works for you
The cool thing about hydroponics is that it is not just one system or only another system. It’s super fun, because you can mix and match certain parts of different setups to build the perfect system for you.
In my experience, there are a a few key things to keep in mind if you are deciding what system to use:
- Outcome: What is the goal of your hydroponics system? Do you want to grow tomatoes? Or do you want to grow lettuce? A system to grow lettuce is completely different from a system to grow tomatoes.
- Yields: Do you want just enough produce to feed yourself? Or do you have hopes of turning your farm into a little side hustle and selling produce?
- Space: How much space do you have for your system? Do you have a lot of vertical height, or a lot of length?
- Budget: How much are you willing to invest into your system? Different price ranges can determine which system is best for you.
- Maintenance: Do you want a system that basically takes care of itself? Or are you okay with spending a few hours each week operating and taking care of your system?
When first dreaming up my hydroponics system, there was some criteria I had in mind:
- I wanted to grow lettuce, and was willing to choose the best setup that supported growing lettuce.
- There was a big wall in my basement that my family was okay with turning into a lettuce oasis. I had 8 feet in height to work with, and 9+ feet in length. So a lack of space for me wasn’t an issue.
- Since I had a lot of vertical height, I wanted to build a system that was vertically stacked.
- I wanted to produce as much lettuce as possible! Enough to supply our veggie based family of 6 with our monstrously large salads each night, and lots of extra to sell to friends and local businesses.
- I was invested in not cutting corners, and that meant buying high quality equipment and building a really good system the first time. So budget wise, while I was conscious to purchase reasonably priced items, I didn’t want to cheap out and make a low quality system that would ultimately have issues and need repairing, costing me even more money in the future.
- I didn’t care how many hours a week it took to maintain the system.
With this in mind, I started sketching designs in my notebook. I ultimately decided on a cross between a NFT system and drip system.
My system overview:
I used 3 inch schedule 40 PVC pipe (which is food grade and water potable) as the growing medium. This is what the plants would grow in. There would be three levels, with four pipes on each level, and 21 inches in between each of these levels. LED grow lights would hang from the wooden 2x4 to the level below it, providing the plants with light and enabling photosynthesis! An 100L reservoir would sit at on the ground with nutrient water, and a pump in the reservoir would constantly circulate this nutrient water throughout all the pipes in the system.
Water travels from the reservoir to the top layer of the pipe by the inlet tube. It snakes around the four pipes in level 3 before dropping down to level 2, snaking through the four pipes in level 2 before dropping down to level 1, snaking through all the pipes in level 1 before flowing back into the reservoir via the outflow tube. This process is constantly repeated. The pump is never turned off, and the water is continually flowing through the system.
If you want to learn more about my system and see my process creating it, check out my video below! You’ll find clips of me building the system, and get to see what my system looks from more angles than a picture can capture.
When I first started researching hydroponics setups, I was overwhelmed by the amount of options for different materials that there was online. This section of the article is meant to be your one-stop-shop for all the materials you will need!
Here is the complete list of all materials I used:
- 3" X 60' PVC pipe
- 1" X 10' PVC pipe
- 90° elbow (24)
- 3" PVC end cap (24)
- LED grow lights
- PVC primer
- PVC glue
- Single outlet air pump: 140L/H
- Eco 633 fixed flow pump : 590 GPH
- Reservoir tank
- Shut off valve
- PVC Union (2)
- Start tray
- Starter tray lights
- Duel Fuel 1
- Duel Fuel 2
- Rock wool
- Net cups
- pH strips
Growing medium: PVC pipe
For the NFT x drip system I wanted, there were a few options for growing mediums: square plastic tray, 4inX4in fence post, circular PVC pipe or square PVC pipe.
None of the stores or warehouses in my city had PVC pipe in a 3 inch diameter, and didn’t have a fence post design that would work for my setup (the ends of the fence post weren’t compatible with end caps so water would leak out). My only other option was to buy PVC pipe off Amazon, which was a really large bill when shipping was factored in. So I waited.
My Dad ended up travelling to a bigger city, and found schedule 40, 3 inch in diameter PVC pipe. We bought 60 feet of this pipe, and cut it at home into 5 feet sections.
So my recommendation to you (if you want to build a hydroponics farm) is to choose a pipe that is relatively cheap and accessible to you. Make sure it meets the following criteria, but if so, you’re good to go!:
- Schedule 40 (you don’t need schedule 80 or any large wall thickness).
- Water potable (this is important! Make sure the pipe is chlorinated PVC (CPVC) and is food and water safe).
- Compatible with end caps (if you’ve chosen PVC pipe like I did, buy the same diameter end caps (e.g. I used 3 inch PVC pipe and bought 3 inch PVC end caps). If you have chosen a square pipe like fence post, double check that there is an end cap that will fit securely on to both ends).
Connections: 90° elbow, 1" PVC pipe, 3" PVC end caps, reservoir
The next big decision I had to make was how to connect these pipes together. To recap, the water will be pumped from the reservoir to the top layer of the system and snake through all the four pipes before dropping down to the middle level, snaking through all four pipes, dropping down to the bottom level and finally draining out ot the reservoir.
So there were three connections I needed to make:
- To connect the four pipes in each layer together so the water can snake through all of them.
- To connect each level together so the water can flow from the top level to the middle level to the bottom level.
- Inflow and outflow tubing, so the water can be pumped from the reservoir to the top layer, and then drain from the bottom layer back into the reservoir.
To connect the pipes in each layer together I used (what I call) an end cap-elbow junction. I drilled a one inch hole in twenty four, 3 inch end caps, and glued a 90° 1 inch elbow into the hole. One of these junctions were glued onto the end of each pipe, and I used 1 inch PVC pipe to connect each junction together:
To connect each level together, I used the same end cap-elbow junction, but facing vertically instead of horizontally. In the middle of each 1" pipe, I glued a PVC union, which means that I can easily detach the pipes to clean or move the system.
For the inflow pipe I used a flexible 1" tube which connected the pump in the reservoir to the end cap-elbow joint in the top layer. For the outflow pipe I used the same 1" hard pipe (that I used for all the other connections) which dropped down through a hole in the reservoir.
Gluing: PVC primer, PVC cement
When buying my materials, I wanted to be extra extra sure that I got the best glue. There were only two criteria I had for this glue: 1) it had to be schedule 40 (water potable and food safe) 2) it had to be good (glue everything together and have no leaks.)
I ended up buying schedule 40 PVC primer and PVC cement from my local hardware store, and I used these for all the gluing in the entire project. There have been no leaks, or open seams, so I am very happy with my decision on both of these brands and would highly recommend.
(PVC primer is applied to the PVC pipe before the cement. The primer acts as a cleaner, removing any grime from the pipe, and it also softens the surface of the pipe, making it easier to glue things onto. The cement is brushed right over the primer and is the ‘glue’ holding everything together. The PVC cement hardens very quick, so I needed to move fast and adhere it to the adjoining pipe.)
Lights: LED grow lights
The options for grow lights are truly endless. I decided on full spectrum LED lights because they emit wavelengths of all colors (red, blue, white, yellow), making them very efficient because they mimic the wavelengths the sun emits. Full spectrum is also nice because it looks like natural light, oppose to purple or red like some grow lights.
I bought these grow lights from Amazon, and screwed two over top of each level. Each light was four feet long, not quite long enough to cover my 5 feet long PVC pipe. If I were to do it again, I would buy 5 foot long lights so the plants on the edges don’t have to grow tall stalks to race for the light.
When designing your hydroponics system, keep in mind that you need at least 12 inches between your plant and the light so they don’t get burned (ideally you should have 16 inches in between plant and grow lights).
Grow lights are supposed to imitate the sun, meaning that they shine for 14–16 hours a day and then are off for the rest of the day. I turn my grow lights on at 6am, and turn them off at 8pm.
Nutrients: Duel Fuel 1 & 2
There is so much research and information online about the “best” hydroponics nutrient brands, how much and how often to add nutrients, and what ratio of NPK is optimal for plants. I was really at a loss, and had no clue which brand of nutrients to choose.
So I asked the owner at my local garden store (who has been growing hydroponically for decades and is very knowledgeable), and he recommended Duel Fuel 1 and 2.
I add 60mL of each into the reservoir once a week, and my plants are happy and healthy.
Water circulation: pump, airstone, air pump
Next on the list is a way to circulate water throughout the system. There are several many gadgets and add-ons that you can buy, but if we keep it simple there are really only three things you need:
- Air pump
I got the Eco 633 fixed flow pump 590 GPH — it’s a good pump, I just regret not getting an adjustable flow pump. Since it is fixed flow, you cannot change the flow rate, and for me, this became an issue. When my system was built and I plugged the pump into the wall and it began pumping water throughout the system as planned. That is, until 15 minutes later when water starting gushing out from the top layer of the pipe.
It turns out, the 590 GPH pump was too powerful for my system, and was pumping water faster than it could drain out, which is why water starting overflowing out the top holes in the system. If I had an adjustable pump, I could easily decrease the amount of water the pump was pumping.
But I didn’t have an adjustable pump. So I bought a plastic flow rate valve and attached it to the inlet tube. And with this I could mechanically block the rate at which water was pumping from the pump. This has been working for the past few months with no issue, so it is always an option if you don’t have an adjustable pump!
The next component is the air stone and airpump. The airpump plugs into an electrical socket and sits beside the reservoir (out of the water), pumping air to the air stone. The air stone is submerged in the reservoir, and slowly releases oxygen into the reservoir.
Seedlings: rock wool, net cups, starter tray, starter tray lights, seeds
Once my system was built, I could move to the real fun: the seedlings. The first thing to think about is your growing medium, what will you plant the seeds in? There are so many options: peat moss, rock wool, clay pellets, rice hulls, hemp cubes, mineral hull and even gravel.
I decided on rock wool, and bought a big cube at my local garden store, as well as 2 inch long net cups to transfer the seedlings into once the roots are long enough. I also bought a starter tray and tiny one foot grow light (top left picture below) to grow my baby lettuce in.
And then I needed the actual seeds, so I got a few packets of lettuce, spinach and mixed greens seeds.
(I would recommend not growing spinach in hydroponics. I have tried several times, and it has never grown well. Most of the time, the seeds don’t even sprout up in the rock wool, and the ones that do are weak and only grow a few inches tall. It turns out that spinach is extremely hard to grow hydroponically. I talked with Arama Kukutai, the CEO of Plenty (one of the largest hydroponics companies in the world) who said that it is even hard to grow spinach in a very controlled, commercial system.
Now that my system has been operating for a few months I have settled into a good rhythm of planting and harvesting. I plant 32 seeds at a time (which is one full level in my system), and in around two weeks when the roots are developed, I put one seedling into a net cup, and put the net cup into a hole in the pipe.
Since I use up the lettuce fast, I am constantly planting new seeds, transferring seedlings into the system and harvesting heads of lettuce. It is a beautiful, never-ending process 🥬🥰.
Costs + links to products
I know when I was creating my system, it would have been helpful to see some ballpark numbers for the price of a larger-than-average, but much-smaller-than-commercial hydroponics farm. So if it’s helpful to see how much my system cost, my grand total was $1612.89.
I have linked each product I bought online below as well. Several products I bought locally, so I have found the closest version to the product I bought and have linked it below. Just know that the product and price may not be the exact same as what you see in my pictures and the prices I list!
*One other important thing to keep in mind when buying products is that light cannot get into the system. All the products you buy should be dark black to prevent any light from getting in. (Light + water = bad bacteria which kills the plants and offsets the pH and natural balance in your system.)*
Hydroponic cost breakdown:
3" X 60' PVC pipe | $619.01
3" PVC end cap (24) | $312.15
Grow lights (3) | $244.04
Eco 633 fixed flow pump 590 GPH | $79.09
1" 90° elbow (24) | $60.2
1 foot starter tray lights | $50.84
Miscellaneous pipe | $34.8
100L reservoir | $24.16
Duel Fuel 1 | $20.99
Duel Fuel 2 | $20.99
Rock wool | $20.32
Starter tray | $20.32
3" PVC union (2) | $19.14
PVC glue | $18.42
Single outlet air pump: 140L/H | $18.06
1" plastic shut off valve | $16.93
PVC primer | $15.53
Seeds | $7.42
Airstone | $6.77
What I would do differently
The above section was meant to show you what TO do, based off what worked well for me. This section is the opposite. It is meant to show you what NOT to do based on mistakes I made and flaws in my design that have become apparent after operating my system for a few months.
- Buy an adjustable pump. As illustrated in the story above, a lot of hassle would have been prevented if I could adjust the flow rate of my pump. It’s definitely easier to make sure you have an adjustable pump instead of dismantling your entire system to put a flow rate valve on the inlet tube.
- Get lights the full length of your system. My system is 5ft long, but the grow lights I got are only 4ft long. I thought that by positioning the lights in the center of the pipe, it would be enough light for the full pipe. And while this does work and it isn’t a major problem, I do wish I got 5ft long lights, because the plants in the grow holes at each end of my pipe (outside the 4ft of the light) are weaker than all the other plants and struggle to get enough light.
- Design your system with cleaning in mind. It is recommended that you clean your entire hydroponics system at least once every three months, and you empty and clean your reservoir once every two weeks (spoiler alert, I don’t clean mine that often 😬). After my system had been operating for 4 months, I knew I had to do a full deep clean of my system. But all my pipes were glued together. Let me tell you, this process of taking my system apart, carrying it from my basement outside to clean it, and then trying to put it back together took longer than it did to actually build my system. I wish I really thought through how to clean my system when I designed it, and made it easy for myself to clean it. Because to be honest, with my design, cleaning the system is a pain in the ass.
- Use wider pipes for the connections. All my connecting pipes (90° elbow, 1" PVC pipe) were 1 inch in diameter. It would be nice to have a slightly larger diameter (even 1.5" or max 2") to allow for better water flow. Currently in my system, roots clog up the 90° elbows and prevent water from circulating through the system. If the elbows and connecting pipes were a larger diameter, it would make it much easier for the water to flush the roots out of the elbow so they don’t plug up the system. (And designing a better way to clean the system would make this a lot easier as well.)
- Set up a planting/harvesting schedule. During the first grow cycle of my system, I just kinda winged it. I planted 96 seeds, and *surprise* they were all ready to harvest at the same time. It was a mad rush to eat and sell the lettuce before it went bad. My advice is to do some planning before you plant your seeds, and decide on how many plants you want to harvest at a time, and work backwards to decide how many to plant and how many weeks you need between each planting cycle.
- Designing a farther distance from pipes to lights. There is exactly 12 inches between the bottom of my PVC pipe and the LED grow lights. If I could re-do it, I would design at least 14 inches in between the pipe and the lights. I’ve found that as the lettuce grows tall (up only a few inches below the lights), and then the tips of the lettuce get burnt. My advice is to make sure you have lots of wiggle room between the pipes and lights so your lettuce leaves don’t get crispy on the top:))
Resources to help you design your system
Here are links to some videos, articles and guides I found helpful when designing my system:
- I have referred back to the Simple Greens website during the designing, creating and operating stages of my hydroponics journey. I bought their hydroponic masterclass which was incredibly helpful for both designing and building my system (would definitely recommend).
- Teen grows sustainable hydroponic farm at home (I took a lot of inspiration from the design of this system).
- The Ultimate Guide To Hydroponic Farming
- 6 DIY Hydroponic Systems
- How to build your own hydroponic system: a beginners guide
- 11 Vertical Hydroponics Systems and Designs for Super Efficiency Freaks!
- Farm in your Garage through Hydroponics Vertical Farming
- Vertical Hydroponic Farm
Welcome to the Creating section of this guide, where I show you step by step how I created my system, and share advice on how to build your own.
Step 1: drilling the holes
When I first bought the 3" PVC pipe, it was 10ft long, so I cut it in half to make my 5ft long growing medium. I was left with 12 of these 3"x5' pipes, four for each level of my system.
I took the PVC into the workshop and started drilling the holes. I ultimately decided on 8 inches in between each hole (8 holes per pipe), and measured and marked where to drill on each pipe with pencil. I just used a drill bit to drill the “starting hole” so it was easier to go in and drill the 3" hole after.
Once all the starting holes were drilled, I attached a 3 inch drill bit to my drill, and drilled the 3" holes from the starter hole.
Once all the holes were drilled, I sanded all of them so there were no ruff edges. And fast forward a few days and all the holes were drilled!
Step 2: the structure + grow lights
Next step was to build the actual structure that the pipes would be supported by. I spent a long time searching the internet for ones I liked/would work for my design. (Pictures of some systems and how they’re set up bellow)
I decided to make the entire structure out of wooden 2x4s, and keep it as simple as possible. It’s basically a big square, with supports that the pipe sits on, and some cross bracing at the back to make it all stable.
I chose wood for the structure because 1) it’s cheaper than PVC, 2) we have a lot of it, 3) my Dad is a carpenter and master of working with wood so he kindly made most of this structure for me! Thank you Dad!
As soon as the structure was made, I screwed on my LED grow lights. I evenly spaced two on each level, hanging from the wooden 2x4 above. (The lights are so nice and bright, it made it much easier to see what I was doing while building the rest of the system:))
Step 3: the connections
Now that the pipes are in place, we need to connect each pipe together, and connect each of the three levels together so water can circulate through the entire system:
To make all the connections, I created end cap-elbow junctions:
- I drilled a 1" hole in the center of a schedule 40, 3" PVC end cap
- I used PVC primer and glue to glue a 1", 90° elbow into the end cap hole
- Let it dry for 5 minutes
- Repeat to make 24 end cap-elbow junctions!
Now time to put those junctions to use — so I glued them onto the PVC pipe, parallel to the ground to connect each pipe together. Then I glued a 1" PVC pipe into the 90° elbow.
Then to connect each level, I glued the junction perpendicular to the ground, and then glued the 1" PVC pipe into the 90° elbow to connect the levels:
And with all these connections made, my setup is officially a closed loop system. There are only two openings (the inflow and outflow tubes) which both drain into the reservoir.
Step 4: Inflow and outflow tubing + union system
At this point, the system was complete except for two crucial elements:
- Inflow tubing: pipe that is attached to the pump, and carries the water from the reservoir to the top layer of the system.
- Outflow tubing: pipe that drains the water from the bottom layer back into the reservoir.
I used a flexible 1" tube for the inflow tubing. One end was attached to the pump inside the reservoir, and the other end was connected to the 90° elbow.
For the outflow tubing, I used the same 1" PVC pipe that I used for the connections. I glued one end into the 90° elbow, and the other end dropped down into the reservoir.
A few days after gluing the inflow/outflow tubing, there were a few problems I needed to fix. So I made two changes to the inflow tube:
- My pump was not adjustable and was pumping water too quickly throughout the system (and as I said in the story above, the water gushed out of the top pipes.) So I cut the flexible inflow tube in the middle, and glued on a plastic, 1" low rate valve. With this, I could mechanically adjust the amount of water being pumped from the reservoir to the top layer of the system.
- After seeing the problem with the pump, I realized that there would probably be many other little hiccups with the system that I would need to fix. And to fix these hiccups, I need easy access to all of the connections and pipes. But my design was glued together and completely connected, which made cleaning or taking it apart so hard. To try and make it a bit easier, I cut the 1" PVC pipe in half and glued on a 1" PVC union. Now I could really easily screw the two half of the pipe apart to clean/inspect/problem solve.
Step 5: pump + airstone
At this point the system itself was built. The last thing to do is connect the pump, airstone and airpump up. I just read the instructions on the box, plugged everything into an electrical socket and let the pump run for a while to make sure it was working okay.
The airstone sits inside the reservoir and is connected to the airpump which sits outside the reservoir. The pump sits inside the reservoir and is connected to the inlet pipe.
Advice for creating your system
- People say it all the time and it sounds cheesy, but “measure twice, cut once”. I learned my lesson pretty fast when drilling the net cup holes in the PVC — I was moving too fast and didn’t double check my measurements, and I screwed up the placement of the hole.
- If you can, I would suggest buying many of your materials in person. I found that this was so much easier because I could physically see and hold the item, and even bring pieces of PVC to see if the 90° elbow would fit (for example). It’s hard to fully envision how everything will fit together until you see it all in your hands. I made a few last minute product changes after seeing the product in person. (e.g. One union I was looking at had ribs in it, which I realized would make for a very uneven glue. So I made the decision to buy the more expensive union with no ribs, so that it would glue into the 1" PVC evenly. This is something that I wouldn’t have realized from the Amazon picture.
- You will have to make the same cut dozens of times. And yes I know it can get boring and you want to do a different job (e.g. if you’re cutting the net cup holes you want to set up the lights), but my suggestion is to set up a super efficient assembly line and finish all of the cuts at once. It makes it a lot easier to put the system together when all the PVC is cut and drilled, oppose to having to go back to the workshop to cut more PVC.
- If you use circular end caps to close off each pipe like I did, I discovered the hard way that drilling the end caps is hard. For my design, I drilled a 1" hole in the center of each (pictures below), and it was not an easy cut to make. The end cap kept rolling around and wouldn’t stay in place. I ended up making a tiny square out of 2x4s which I stuck each end cap in so it couldn’t move as I was drilling it. This helped a lot, and I would recommend you to do this for any circular/hard to cut material.
Resources to help with building your system
Links to some videos and articles I found helpful:
- Building a Home Hydroponic Rail System (this is the best video I found showing step-by-step creating a hydroponics system. I modelled a lot of my design and building process off this video.) I also used the masterclass and course on their website.
- How To Make inexpensive Hydroponic System and start Hydroponics Garden At home
- DIY Best Vertical A-Frame Hydroponic Garden Farm Build
- Hydroponics at Home
- How I Built My DIY Hydroponic System & Hydroponic Garden
- DIY | How To Build Your Own Hydroponics System.
- How To Make Your Own DIY hydroponic System AT Home
The final section of this guide is dedicating to the ongoing process of keeping your system up-and-running. We will cover everything from planting + harvesting, to cleaning the system, and maintaining a good pH and nutrient level.
Planting and harvesting schedule
I use rock wool as my growing medium, but there are many other options (as explained in the Materials section!) like peat moss, clay pellets, rice hulls, hemp cubes, mineral hull and even gravel.
I have a small starter tray which the rock wool cube sits in, and a small 1 foot grow light which speeds up my sprouting process.
During my first grow cycle, I planted seeds in the entire rock wool cube (112 seedlings) which I would not recommend! They were all ready to harvest at the same time *surprise* and it was a mad rush to eat and sell all the lettuce heads before they went bad. I learned my lesson, and now I have a planting and harvesting cycle.
It sounds more fancy than it is — all a planting schedule is, is a plan on how many seedlings to plant and how often. It can include specific dates (every 14 days I will plant 36 seedlings), or it can be more circumstantial (after the lettuce in one level is 4 inches tall I will plant 36 seedlings).
Having a systematic approach to planting and harvesting (has pleased my inner control freak) and makes sure I have a constant supply of lettuce.
Here’s an example of what a planting schedule can look like (it’s my schedule:))
- Plant 36 seedlings in rock wool cubes
- Check on them in 1.5 weeks. If roots are at least 1.5 inches long, move into the hydroponics system. If they are less than 1.5 inch keep them in the start tray for the rest of the week.
- Cut the rock wool cubes (careful not to break the roots) and put in net cups. Put the next cups in one layer of the system.
- Plant new seeds 1 week after seedlings get transplanted to hydroponic system.
- Start harvesting lettuce 6 weeks after transplant
Just spend a few minutes planning how much lettuce you need and how often you want it, then work backwards to find when you need to plant the seeds and when you need to harvest.
pH and nutrients
The brand of nutrients I use is Duel Fuel. I love it because it takes zero effort, is on the cheaper side of nutrients and is dead easy to use. There are so many options out there, but I have been very happy with Duel Fuel.
I use an equal combination of Duel Fuel 1 and Duel Fuel 2. DF1 is nitrogen heavy (but also contains micronutrients like calcium, copper, iron and zin), and DF2 is phosphorus and potassium heavy (and also contains magnesium and sulfur).
The nutrients come with a very comprehensible feeding program — every week (based on weather the plants are in the vegetative or flowering stage) it tells you exactly how much of each nutrient to put into the reservoir. Since each level in my system is staggered (just as one level is reaching peak size I plant tiny seedlings in another level), I put the same amount of nutrients in each week (since I have an 100L reservoir, I add 60mL of DF1 and DF2 in the reservoir every week).
(I bought the Duel Fuel at a local garden store, but you can also buy it online.)
The pH of the hydroponics reservoir should be between 5.5 and 6.5. If the pH is too low (acidic) or high (alkaline), the plants wont be able to absorb important nutrients, their growth will be stunted, and the plants will eventually die. So it is super important to keep the pH of your reservoir in between 5.5 and 6.5.
When first starting out with hydroponics, I was nervous that it would be hard to keep the pH within the 6.6–6.5 range, but I have actually been surprised at how easy this has been! Most nutrients are stabilizing, which means that if they are added in proper amounts, they naturally stabilize the pH of the water to 5.5–6.5
Just to make sure the pH stays in this range, I have pH stripes. They are thin strips of litmus paper which measure the concentration of hydrogen (and subsequently the pH!) of the water. You stick the strip in the reservoir for 5 seconds, and when you pull it out it turns a color, and you can match the color to the key on the package to see what the pH is. In half a year of operating my system, the pH has never been outside 5.5–6.5, so I would recommend using stabilizing nutrients!
My biggest mistake is that I didn’t design or create my system with the cleaning process in mind. And because of this, it is an absolute pain in the ass to clean. I end up spilling 100L of water across my basement floor, cutting the already glued pipe to take the system apart and carrying four, five foot long PVC pipes up my basement stairs at once. It was not fun.
So my biggest piece of advice is to design your system in a way that it can be easily taken apart to be cleaned. If I could design it again, I would put a PVC union in the middle of each pipe connection, so each individual pipe could just be screwed apart from each other.
Anyway, now for the cleaning process: I used 5L of 60% hydrogen peroxide diluted in 50L of water (you are supposed to use 1:10 ratio of chemical to water). I carried each level of the system (our interconnected PVC pipes) outside, and rinsed them for a long time with my garden hose. Then with a long brush, I rubbed the diluted hydrogen peroxide everywhere throughout the inside of the system. And then I turned the garden hose on high and let the water circulate throughout the entire system (I had to make sure there was no trace of hydrogen peroxide left, because even a small amount would kill the plants.)
A few pieces of advice specific to cleaning your system:
- Wear gloves (I didn’t at the beginning. And then I splashed hydrogen peroxide on me. And it kind of burned lol)
- Experiment with ways to clean your system in place, so you don’t need to take it apart and carry it outside like I did. Because this was a lot of extra work.
- Use a pressure washer or a hose that has a high pressure setting/flow rate. I found that it was so much easier to flush all the roots and dirt out with the high pressure, and I wouldn’t have been able to with a regular flow of water.
- Soak the pump, airstone, inflow/outflow tubes (and any other connections that can be detached), before scrubbing. I usually soak all the smaller components of my system in diluted hydrogen peroxide for the entire time it takes me to clean the PVC pipes (2+ hours), which loosens all the grub and debris that is caked in the small crevices of the system.
- Use a brush with a long handle to clean the PVC pipe. My PVC pipe is 5 feet long, making it super hard to clean with a tiny brush. I drove all over town to eventually find a firm 2.5inch in diameter bristled brush with a 2 foot long handle.
- Make sure you clean the hard to reach areas (like the 90° elbows, narrow tubing, 1 inch PVC pipe) well! These are the parts of the system where roots and grub are most likely to build up, so you need to really clean these areas well. I stuck my hose right into the 90° elbows and 1 inch tubing, but you could also buy a small in diameter brush, or use a syringe or small brush.
- And lastly, utilize gravity to your advantage! Hold or prop the PVC pipe vertically so as you’re blasting the pipes with water, 1) the water can easily be flushed out of the system and 2) even more roots and dirt is dislodged since high pressure water + gravity = a deadly combo.
And here comes the fun part ✨harvesting✨
With my design, I harvest 96 heads of lettuce every 6 weeks, adding up to a total of over six hundred heads of lettuce a year!
A really cool thing about hydroponics is that plants survive for 20% longer in nutrient water compared to soil. What I’ve found is that once the lettuce hits it’s “prime” (after 6–7 weeks of being in the system), it can survive without dying for another 3+ weeks. It just keeps growing taller and taller, and the only ‘problem’ with the lettuce is that the tops get burnt as they grow close to the lights. (But that is easily addressed by cutting the tips of the lettuce off before you eat it).
Resources to help with the operating process
Here are some articles, videos and guides that I found helpful to navigate managing a small hydroponic farm!
- How to Clean a Hydroponic System with Hydrogen Peroxide
- pH in Hydroponics: How to Maintain the pH Levels of Hydroponic Systems
- Small-scale hydroponics
- Perpetual Harvest — Get The Most Out Of Your Grow Room
- How To Maintain Your Hydroponics Reservoir
I hope that this guide has helped you in some way, shape or form along your hydroponics journey. Feel free to refer back to this article whenever you’re stuck, or check out the video tour of my hydroponic farm so you can get a better sense of how it all connects together and how I made it.
If you need help with something specific during the process of designing, building or operating your system, make sure to check out the resources linked throughout this guide — I included links to articles and videos that I modelled my system off and continue to use. I also used this hydroponics course by Simple Greens which helped me a lot with my hydroponics farm.
Let me end by sharing my crazy vision for the (not so distant) future of humanity.
I imagine a future where every individual or household grows enough fruits and vegetables to feed themselves in their own house! Where every home, apartment, condo, has a 10 foot wall dedicated to growing their own food.
And by doing this, greenhouse gas emissions from agriculture would be greatly reduced, people across the world no matter the climate they lived in would have access to high quality food, and we wouldn’t be flying food all the way from New Zealand to the U.S.A.
Maybe one day this dream of mine will manifest. But until then, I’ll be over here, operating my little hydroponics farm!