In the past decade, there has been a sharp increase in our interest in food production. We have gone from being largely uninformed omnivores to checking the labels on most things we buy. Beyond that, now we are aware of water scarcity concerns and working conditions behind imported foods. In response, a curious amount of people around the world have taken to growing some or all of their own food at home: all without buying land or spending time in the scorching sun by using hydroponics which consumes 90% less water than conventional agriculture. In this thorough guide, we will present you with the know-how on starting, maintaining, and enjoying your own successful hydroponic system.
What is Hydroponics?
Growing Plants in Space?
In elementary school, we were taught that soil is a requirement for plant survival. Hydroponics have effectively defeated that notion when it first grew 25-foot tall tomato vines with just water and nutrients. Given the versatility of hydroponics, this alternative farming technique has already been used by NASA in outer space to produce food and is a big part of the upcoming Mars mission. Basically, hydroponics is the art of growing plants without the need for any soil
Why Do Plants Prefer it to Traditional Farming?
Hydroponic growing usually happens with plant roots immersed in nutrient-rich water where the plants are able to quickly take in any necessities, such as: water, mineral, nutrients, and oxygen. Plants growing in the ground usually do not have all their needs available directly next to their roots, so they put energy into growing more roots to explore the soil until they find what they are looking for. This is energy spent on exploration which could instead have been used on producing more leaves and fruits for our consumption. This also means that plants have smaller root systems that allow them to grow closer to their neighbors.In other terms: this means that you can grow more lettuce in your closet per square foot than you could outdoors with the same amount of area. Hence, hydroponic plants tend to give substantially higher yields than those grown traditionally; both per plant and per square foot! The most popular form of hydroponics is known as the nutrient film technique or NFT. This technique holds plants afloat and in place with a variety of small containers and then has water constantly running through the roots, like a river, carrying a vast amount of nutrients straight to the roots of the plant. An air pump is typically involved, which allows for the water to be constantly aerated; contrary to what you might think, roots need oxygen in order to take up nutrients and to keep the rest of the plant functioning. Plants growing in water without oxygen will typically not survive very long. With growing concerns of diseases, like E. coli, transmitted to humans from food, hydroponics also offers a more sanitary means for food production since soil is the medium where most of these diseases are harbored. Aside from our health, plants are also less susceptible to diseases in a hydroponic system for the same reason, which reduces the number of plants lost to disease.
Hydroponics for a Healthier Planet!
Aside from these benefits to hydroponics, these systems typically use 90% less water per plant than in conventional agriculture. We are living in a world where droughts are happening more often, crops are drying out in fields and leaving farms out of business, historic bodies of water are drying out, and international conflicts are happening over water usage. By delivering water directly to the roots, removing the possibility of excess irrigation, and minimizing evaporation rates, hydroponics has offered the world a way to produce higher amounts of food with much less water. Hydroponics is also about democratizing the production of food for all of us. No longer is it necessary to buy an exorbitantly expensive plot of land to feed your family! Hydroponics will allow you to grow food in your closet, kitchen, and even roof. The implications of hydroponics could allow food deserts to become food resilient centers where gas station snacks become a thing of the past. Food production is now possible at every home for a minor investment of time and money.
How do Plants Work?
In a surge of excitement, you might be tempted to drop a few seeds of lettuce in a cup of water to begin your first hydroponic system. Not so fast! First, you will need to understand how a plant works. Plants are complex organisms that have as vast a range of attributes as they have needs.
As any complex organism, plants have cells that are specialized in certain functions, such as: structural support, transport of nutrients, making roots, converting light into food, and breathing! Interesting groups of these cells together usually present themselves as noticeable parts of the plant, such as: roots, stems, and flowers. Let’s go from top to bottom:
Flowers! The section of the plant that has been depicted in art across the world for millennia. Being the biological creatures that we are, flowers are as attractive to us as they are to butterflies and bees. Known as the sexual organ of the plant, the purpose of flowers is to reproduce. Pollinators are attracted to the flowers with a beautiful array of colors and the promise of delicious nectar. Little does the pollinator know that the nectar is in exchange for the transport of pollen to the next flower. Through the exchange of pollen between plants, fertilization occurs which then causes the ovary to swell up into a fruit! Broccoli, artichokes, brussel sprouts, and capers are examples of flowers we eat.
But why would a plant put so much effort into making such a tasty fruit? Fruits serve as another attractive mechanism of a plant. With bright colors comes the promise of delicious and nutritious delights. Once most organisms consume fruit, they travel to another area where they will eventually relieve themselves. The seeds pass through the digestive system unscathed and land on a source of natural fertilizer. Over millions of years of evolution, plants figured out how to fool organisms for mutual gains.
Leaves have the function of absorbing sunlight to convert into usable energy and food. Aside from being an ancient functional solar panel, leaves serve as the lungs of the plant! Leaves gather carbon dioxide from the air and then, simply put, release oxygen as a byproduct. This is one manufacturing byproduct that we can only hope increases in our struggling environment. With our naked eyes, we can observe curious veins on the surface of leaves; the reason for these is to transport chemical energy to the rest of the plant and to receive nutrients/water from other sections. Collard greens, lettuce, kale, and spinach are examples of leaves we eat.
Stems are the strong highway of the plant, serving as the structural support for strong winds and transporting minerals, water, and nutrients all over the plant. Asparagus, celery, and sugarcane are examples of stems we eat.
Last but not least, roots are the underground support network that anchors the plants, explores and absorbs water and nutrients, breathes for metabolism, and stores energy. Root networks are typically as big underground as the plant is above ground and can even be said to be the most important organ of the plant. We eat many roots such as carrots, beets, and potatoes. In review, plants need water, light, oxygen, carbon dioxide, minerals, and nutrients to grow. A plant will not survive if even one of these is lacking.
You Eat Plants. What do Plants Eat?
Dumping some of your old lawn fertilizer or fresh cow manure in your hydroponic system won’t quite do the trick! The nutrient requirements of your hydroponic plants are a complex topic that could be as simple as pouring known formulas or as difficult as trying to build a rocket; your choice.
Plants have a long list of nutrients they need for growth. These can be categorized into macronutrients, needed in large quantities, and micronutrients, needed in smaller quantities.
The necessary macronutrients are: Carbon (C), Hydrogen (H), Oxygen (O), Nitrogen (N), Phosphorus (P), Potassium (K), Calcium (Ca), Sulfur (S), and Magnesium (Mg). The first three can be found in sufficient quantity in the air and need not be applied to the system through any solution.
The micronutrients are: Iron (Fe), Chlorine (Cl), Manganese (Mn), Boron (B), Zinc (Zn), Copper (Cu), and Molybdenum (Mo) where some plants may also require Iron (Fe), Chlorine (Cl), Manganese (Mn), Boron (B), Zinc (Zn), Copper (Cu), and Molybdenum (Mo).
Before you let this list make your head spin – you have no need to worry! A variety of stores sell ready-made soluble hydroponic solutions at pennies per gallon. With proper monitoring, feeding your plants is as simple as pouring the recommended doses into the water. As the plant goes through its different growing stages there is also a different kind of nutrient solution necessary.
But, it is not as easy as just pouring solutions in and watching your plants go: you will also have to sample your water often for pH and electroconductivity which can be used to determine how much of the nutrient solution remains. Otherwise, in a closed system, just flush and completely renew the nutrient solution every two weeks.
It is also important to remember that testing is vital. Water should be tested often for the appropriate pH and temperature that the specific plants require for optimal growing. Changes in pH can prevent a plant from taking up a nutrient it needs to continue developing.
Growing Mediums: No Soil Necessary!
Typically, plants in a hydroponic system do not just sit freely in water. Mediums, a substitute for soil, are used in hydroponics to hold the plant in place. Plants can have the protection of a growing medium from falling over, from drying out if the system malfunctions, from sudden fluctuations in pH, and by allowing for more efficient aeration near the roots. The list of available mediums is rather extensive, so here we outline some of the more common ones that we do and do not recommend for hydroponic farming beginners.
Expanded Clay Pellets
Expanded clay pellets are one of the most convenient media that become even more versatile when mixed with other more lightweight mediums. Clay pellets are made by heating small balls of clay which causes them to expand into larger balls that feel like a clay pot. Clay pellets do not retain water too well so they drain quickly, do not clog up the rest of the system, and are basically inert with a neutral pH and no added nutrients. Conveniently, these pellets also can be reused over and over again which can be an attractive trait to you given that there is a usually noticeable investment needed to begin a system. Clay pellets can be rather heavy alone, which could test the structural integrity of your hydroponic farm, so it is best to mix them with a medium like vermiculite or coconut coir.
Coconut coir is one of the most preferred mediums given that they are made from disposed coconut husks which would just go to waste otherwise. Unlike peat moss, coconut coir has a small carbon footprint and does not need to be mined from the ground in an unsustainable manner as are some growing mediums. This medium allows for a healthy balance of water retention, aeration, fungal protection, and pH buffer. Coconut coir can also be reused if handled correctly and treated for any diseases that it could be harboring from the last crop. A downside to the use of coconut coir is that small particles could go on to clog filters and pipes in the system.
Rockwool is an interestingly innovative material that is made from melted rocks that are spun into thin fibers to make a material almost indistinguishable from carbon fiber. For the sake of larger-scale production, rockwool is very easy to use as it allows for maximum aeration to roots, is lightweight, and is relatively affordable. This medium can be used throughout the entire lifespan of the plants. Unfortunately, rockwool has a set of drawbacks that make it less attractive to beginners and household hydroponic gardens. Rockwool cannot be reused which makes it difficult to dispose of due to it not being biodegradable. During handling, it also releases a sort of dust that is considered very harmful to our health. The ideal medium should be biodegradable, safe to use, and also reusable for many more times!
Perlite is the tiny peanut-looking white things you find in potted store plants. You have probably picked them up before to realize they do not weigh very much and can crumble into dust if you apply a little pressure. Perlite is nothing but flakes of glass expanded by heating. Equipped with both a high water retention rate and good drainage, perlite has become a favorite among hydroponic enthusiasts. Perlite can also be reused several times and should be held in place with a mesh to prevent floating away.
Choosing Your First System
You now know all about the intricacies of hydroponics but are still missing the most important piece: the variety of systems that can be possibly used in hydroponics! It is safe to say that a new system comes out on the market every few months with a pitch that makes it seem like the best hydroponic system known to man.
The truth is that all systems have their benefits and drawbacks depending on: what you want to grow, how much quantity you would like to yield, and how much time and money you would like to invest. There is no “best” hydroponic system but here we will outline our common favorites that continue to give reliable results.
In our experience, Water Culture Systems are the simplest of hydroponic systems. In these systems, plants are suspended in the water using a floating foam platform. Each plant is in a hole on the platform where it is held with its medium of choice. Underneath the platform is a constant supply of water with nutrients that is always in contact with the plant roots.In order to not suffocate roots, an aerator pump is installed in the water. Given that there is no flow, water is flushed out every two weeks and refreshed with a new dosage of nutrient solution. Some would add a reservoir from where water is exchanged constantly with a filter in order to keep up a steady supply of nutrients and minimize disease dangers. Due to its simplicity, the water culture system is both easy to maintain and affordable to build.
Flood and Drain
The Flood and Drain system is as popular as it is simple. It basically consists of a plant tray, a reservoir that contains water and nutrients, a submersible pump, and a timer. The tray is a container of any size which can hold the hydroponic medium and plants stable without the need for flotation. The tray is then flooded with nutrient water from the reservoir two to four times a day at approximately 30 minutes each: this equates to 15 minutes of flooding and 15 minutes of draining per cycle. This will allow you to fine-tune the water and nutrients of your plants for optimal conditions and yields. Of course, this system needs to be monitored frequently as a failure to flood on time could leave plants without water for longer than they can withstand. Similar to the Water Culture system, this is a system that can be built at home very affordably.
Perhaps the highest yielding of the hydroponic systems is the Continuous Flow System due to its, you guessed it, continuous flow of nutrient-rich water throughout the plant roots. This system requires only one reservoir for any number of plants you desire. The reservoir can be positioned anywhere and contains a submersible pump that sends water to the containers the plants are located in. This plant container is held at an incline where it has a drain tube at the end that sends water back to the reservoir. The one-reservoir system allows for centralized control of nutrients, pH, and temperature. Also known as a Nutrient Film System, the Continuous Flow System must be aerated at all times from the reservoir.
Although many hydroponic growers enjoy the benefits of keeping their hydroponic systems near to a south-facing window, some resort to using artificial lights in order to not be limited by the variance of sunlight and to maximize yields. Your common household incandescent light bulb won’t do the trick and will make your energy bill skyrocket!
Different types of fluorescent, HID or high-intensity discharge, and LEDs or light emitting diodes are used to grow plants. Their timing and intensity will usually vary drastically by the type of plants you are trying to grow. Plants you are producing for leaf consumption, like lettuce, will typically require an intense and continuous light for the entirety of their lives. Fruiting plants, like strawberries, will require intense and continuous lights during the vegetative stage with a switch to less intense and shorter light times for when it is time to fruit. The manipulation of lights can simulate seasons to plants which will typically cause a noticeable physiological change to happen.
Common First Problems
Here we will outline some common issues that occur in hydroponics. We will cover what they could mean and what to do:
Drop In Water Level
Over time you might notice that your water levels are dropping. If it happens slowly, it could be because of natural evaporation and can be simply fixed by filling the system with more water to compensate. This could also be due to plants successfully taking up enough water as they are supposed to! If the water level drops too quickly then you might have a leak! Revise the system thoroughly for any leaks where tubes meet, in corners, and where the structural integrity might be put to the test. Leaks should only be fixed with food-grade labeled materials such as food-grade silicone.
Although you might be relieved that you no longer have to worry about weeds in your garden, algae can have the same detrimental effect. Not only does algae reproduce and grow very quickly, it can also deprive your system of all the nutrients needed for your plants to continue thriving. Algae can clog pipes and deprive plants of necessary oxygen. In short, algae means bad news! An algae issue can be resolved by keeping the nutrient solution reservoir as shaded as possible. Algae will die out without a light source. If your plants are old enough you can also add a little amount of hydrogen peroxide to the water to act as an algicide.
Clogs in a system can cause a certain part to overflow or dry out. Clogs, if left unattended, can be very problematic in a hydroponic system. They are also a more likely occurrence in systems which use small diameter tubing for higher pressure like drip-irrigated system. Clogs can be remediated by removing tubing and flushing them out with air, hot water, or a pipe cleaner. In order to avoid clogs, we recommend that beginners use systems such as flood-drain and continuous flow which have large tubing parts that rarely clog.
Let’s Get Started!
Now that you know all the basics of hydroponic growing, you are ready to get started! We would recommend getting started with lettuces since they are plants that grow easily without many adjustments and can be replaced easily if you make any mistakes at first.
Experience, in reality, is the best way to master the art of hydroponic gardens. Soon you will be impressing guests at your home with a functioning system that could have produced the salad they are about to eat; imagine that for an opening conversation!