Hydroponics 101: An Overview for Beginners

What is hydroponics? Simply, it is growing plants in an inert or no growing medium. Plant growth is made possible (in every form of hydroponics) by highly aerated water! 

What are the benefits of hydroponics? 

Hydroponics can successfully grow crops in an incredibly small amount of space, making it appealing to, although not exclusive to, indoor growers. Hydroponics maintains much more control of plant nutrition, and we can make precise adjustments to fertilizer needs. One of my favorite aspects of hydroponics is complete and total pH control. This really is the only way to get the most out of your nutrients and plants.

Key Advantages of Hydroponics

1. Higher Efficiency in hydroponics is one of the main draws, particularly in urban areas. Soil is in short supply, and some grow media can be sterilized and reused almost indefinitely. While I would encourage you to use formulated fertilizer and nutrient mixes until you get your feet under you, almost everything you use to feed your plants can be shipped dry. This means you can efficiently get the needed materials to grow large amounts of fresh produce in an urban area or an indoor grow in sub-zero conditions (which can ruin liquid fertilizers) without needing any sort of heavy equipment or loading dock. 
2. Faster Growth Rates can be realized when we are able to focus on the nutritional requirements of our crops and couple that with the ideal pH. The proper pH makes nutrients as available for the plants to absorb as possible. Since the plant's root system is constantly submerged in, flooded by, or sprayed with the nutrient solution, the plants are going to continue to grow and reach for more light and nourishment as quickly as they are genetically allowed to.
3. Heavier Yields are often seen in hydroponics. The aerated nutrient solution is constantly being brought to or being replenished around the plant's root system. This allows the plant to absorb all of the nutrition that it possibly can whenever the processes in the plant will enable it to. If ALL other environmental factors are working in sync for the particular crop you are growing, you will see the highest yields the genetics of your crop can produce.

Drawbacks to Hydroponics

The disadvantage of hydroponics would include the speed at which failure can arise. With all of the fast and large yields, we are also plagued with the unfortunate truth that sometimes, electronics fail/break/ or wear out. The most visible job in a hydroponic operation is the harvesting of exceptionally clean produce; however, the least visible job is equally vital. The maintenance and cleaning duties are essential to production. If the wrong part breaks or an air pump goes down, one afternoon of fun turns into your grow, taking two months of steps back. Some systems have more of a tolerance between equipment failure and complete crop loss. 

Why Hydroponics is Tough

Hydroponics is a tougher grow method for new growers (emotionally). While I do not tend to agree that hydroponics is difficult, I started out 15 or so years ago with an 18-liter tote, a desk lamp with a CFL bulb and an air pump, and stones from Target. It sure can be disappointing if it fails. 

The only “specialized equipment” I purchased were six 2” net pots and a small package of rock wool cubes. I was off and running! And I had produced some large tomatoes for living in a small studio apartment. One day, I came home from work, and my air pump died! Thankfully, being a DWC setup, the roots did remain immersed in water. This was lucky, but my first run-in with equipment failure did lead to the tomatoes shedding half of their leaves and me not getting any ripe tomatoes for a couple of months. If I had been running aeroponics and my pump had died, the plants would have had less than an hour before survival rates plummeted into the single digits. 

As a beginner, I highly recommend sticking with systems that have the fewest pumps and timers. Always invest in redundancy of any hydroponic system as soon as you can afford to; extra pumps, air stones, hoses, timers, emitters, etc., are extremely hard to substitute when things have gone sideways.

Hydroponic Systems Are An Investment, as we are all too familiar with; many components' prices are indicative of quality, and when we are talking about pumps, that is a certainty. I have used cheap pumps, and I have paid the price! Flood tables, Gutters, Dutch Buckets, and Net Pot Lids all cost a pretty penny, but if you keep up on cleaning and maintenance, these components can last for many years. The added benefit of all of these components is if they are cared for, they can be brought along to another grow at another location, sold secondhand, or used in different configurations.

Hydroponic Grow Media Options

All hydroponic grow media require rot resistance. They provide negligible, if any, nutrition to the crop.

Hemp Mats and Plugs

Hemp-based products are a newer media now available for hydroponic growing. Hemp fibers hold over 10 times their weight in water, making them excellent for flood and drain systems. We use hemp mats in our grow rack for growing microgreens.

Because the mats don’t contain loose fiber like coco coir, they keep the reservoir cleaner and limit the number of waterings per day. Plugs made of hemp make a good replacement for the more traditional rockwool. They are sustainable and compostable, unlike rockwool. 

Rockwool

This is going to sound a little wild, but Rockwool is exactly what it sounds like!? Rockwool begins life as a rock and is super-heated and spun at high speed, creating strands of “wool” made from rock. Rockwool was originally developed as an insulation ( and is still used as such; it is a fantastic sound deadener and an insulator from heat!)

Rockwool does not rot, and it does not grow mold. It is, however, likely to get algae on the blocks when exposed to light over the growth cycle. Rockwool does come with one downside. It does need to be disposed of properly as it will not rot or compost.

Clay Pebbles/Grow 

The clay stones can be sterilized and reused! Clay pebbles, Hydroton, expanded clay pellets...they come by many, many names, but chances are you have already seen these brown clay balls with a black interior. They are fantastic as a reusable grow media. Once you bring them into your grow operation, I will warn you that they will forever be a part of your growth. You will never get them all cleaned up, and if you think a Lego is a drag to step on, I have some terrible news.

The roly-poly nature of our clay media is a downside, but the amount of uses and ease of sterilizing them for years to come outweigh the frustrations. I even like to add the clay pebbles to potted plants in the soil as a sort of “fortress” to hold moisture and oxygen for microbes and fungi to colonize/survive dry spells or heat waves.

Coco, or coco coir

Coco coir is made from coconut husk. Coco coir generally comes in a compressed brick form. Much like the “Dino-Pills”  children bring home from the museum gift shop, you add water, and they grow to fill a container much larger than their packaged size (different companies compress at different pressures, so expansion will vary.) 

This product is more complex than it seems. Coconut husk has been a “waste” product from the coconut milk and coconut water industry. It has been an economic boon for some areas of the world that otherwise are quite limited in their access to tradeable resources. This has led to some people cashing in on this at the expense of your budget-conscious grower. 

Coconuts tend to grow in areas with proximity to seawater. I have heard many stories about shady overseas sellers selling salt-saturated coir in bulk. Some cheap websites have constantly been coming and going, offering the promise of an extraordinary amount of coco for the money. It seems in some areas, they do not have access to fresh water, and sometimes, it appears people are dumping coco they know is salt-saturated. 

The point being, buy your coco from a known source. There are thousands of reputable places to buy coco, and the prices are generally in line with one another. If, for whatever reason, you do end up with salted coco, soak it in RO water, flush it with Reverse Osmosis (RO) water, and then repeat. Test the PPM of the water each time, and you will want to get that reading as close to 0 as you can. Just 50 ppm of sodium chloride will cook strawberries.

What are the different types of hydroponic systems?

Deep water culture (DWC) systems 

Deep water culture is where my self-taught hydroponics journey began: dead simple, with the least failure points, and the most forgiving. The name says it all: we will be growing (culturing) in deep water. The depth of the water is usually at least 18” deep. 5-gallon buckets are very popular for DWC as quite a few companies are making DWC Lids for 5-gallon buckets. Raft beds are also a form of deep water culture. Raft beds are big pond liners with a frame to support the huge amount of water they hold.

On the surface will float a raft made of buoyant material. The raft will have even spaced holes that allow the plant's roots to grow into the water in the pond liner. A raft bed will grow literally anything you have the buoyancy for ( a 2’x4’ 1.5” piece of polystyrene foam can support 55lbs if balanced on the board).

Bootstrap Farmer's Deep Water Greens Rafts are coated with a with polyurea coating, eliminating many of the common issues growers have with deep water rafts breaking down adding to replacement costs.

Deep water culture can be simple, but it also can be labor intensive, depending on how simple and how large the system is. If we are talking about 5-gallon buckets with net pot lids and a multiple outlet air pump feeding an air stone in each bucket, things start to get fairly busy when we get beyond a dozen or so.

Hydroponic drip systems 

These systems are very similar to soil drip irrigation using drip stakes or “button” emitters. This is a low-flow, low-pressure system, and the only difference over soil container growing with drip irrigation is the fact we are growing in a soilless medium. This does open up a few possibilities for us. If we use a media that holds water well, we can limit our irrigation cycles down to even once a day in some instances.

This can lead to your reservoir staying clean for longer because we are contaminating the solution less with our media. Some media can handle near-constant drip without detriment to the plants’ root systems and can be sterilized over and over again.

Dutch Buckets 

This type of growing was originally developed in Europe. There are many iterations and even some DIY plans to make Dutch buckets yourself. Dutch buckets are special because they have a drain that is designed to get all of the water out of the bottom of the bucket and prevent a buildup of contaminants and algae etc., that builds a sort of sludge in the bottom of a reservoir. This helps to keep the system running consistently and may require less cleaning. Dutch buckets can irrigate on a timer or flow continuously ( this is a source of hours-long discussions online.) As with any system, what works for me may not be your preference.

Aeroponic systems

Aeroponic systems are the most sensitive, but they can yield unbelievable results for the space they require. Aeroponic systems grow plants without media! The plants are supported by a flexible rubber or neoprene collar that holds the plants at the base. For large plants, trellises can be used. 

Aeroponics uses small misters or micro sprinklers to spray plant roots directly, also known as focal feed. The fine droplets are near a mist, and this allows an incredible amount of oxygen to be available for the roots. Aeroponic sprayers mist the roots on short intervals up to a  constant spray (this can be a source of disagreement. Either works, in my experience.) This system can also run without an air stone/pump, although I always like to remind people you can never aerate your nutrient solutions too much and have yet to see evidence otherwise. 

Ebb and Flow Systems 

These are some of the most common types of systems. They are also known as flood and drain tables. You have probably seen one of these large tables, usually 4-8” deep, with a reservoir underneath. These are a great system that takes advantage of a sort of accelerated bounty-famine cycle in which the plants are flooded with nutrient solution, and the plants are grown in pots of soilless media. The table is then drained, and the plants are not flooded again until just before the soil media is going to become too dry for the plants. The media, container size, and frequency of irrigation events are all determined by the environment of the grow and the crop being grown. With this simple system, you can grow nearly any crop with one timer, one water pump, and one air pump. 

What is the best hydroponic system?

The best hydroponic system is the one you have the time and patience for. You need to maintain a system to succeed. The best system is the one that has a maintenance and cleaning routine that you will follow consistently. I have built many systems, and every time I convinced myself an annoyance would be acceptable, it was a source of problems. We tend to be optimistic during the build about what we are willing to accept day in and day out for years. While you are setting up, take the extra steps to ensure the system is accessible for daily operations but also for cleaning and maintenance. Ensure components that will wear or are consumable are accessible while the system can be disturbed as little as possible. 

Breakdown of Hydroponic System Components

Breaking down hydroponic system components and accessories is actually very easy. We can find everything we are going to use in multiple industries. Below we will cover air pumps, air stones, water pumps, filtration systems, water chillers or heaters, and water testing meters.

Air Pumps, Air Stones and Water Pumps for Hydroponics

Air pumps and air stones provide oxygen to plants - the most critical aspect of your entire system. These are the “diaphragm and lungs” of your hydroponic system, and they are going to be necessary in ALL systems. Since oxygen is not soluble in water, it is incredibly vital that we get as much air into our system as possible (air is only about 21% oxygen! And the plants want oxygen specifically for the roots to breathe, grow, and take up the nutrients the plants need).

Air pumps have never been more available for the hydroponic grower. You can order one online, but chances are you can find one at a hydroponic store in your area. Get the biggest pump you can afford. You can NOT go too big.
Tip: If you don’t have a hydroponic supply store near you, air pumps are ubiquitous in freshwater and saltwater aquariums and are meant to run 24/7. This means most pet supply and aquarium stores will carry pumps and extra stones. 

Air stones are probably the most overlooked part of any hydroponic system. Air stones vary greatly in price. You will quickly notice it is not necessarily based on size. This is because the quality varies greatly as well. Air stones are how we get our water aerated, and they are going to be the most vital. Any air pump will blow bubbles, but the stones dictate how fine the bubbles are. 

Bubble size is extremely important because the atmosphere is only 21% oxygen, so we have our work cut out for us. Smaller bubbles, being emitted at the deepest point of your reservoir, are going to mix more oxygen into the water. Lower oxygen levels lead to contamination of the reservoir, root rots, and slimes. 

With every flush, you will want to clean your air stones thoroughly with a gentle cleaner. Yes, cleaning your stones will eventually degrade them. They are what many industries call a consumable. This simply means they are sacrificed for the greater good. For your hydroponics system to function properly, you will need to make sure to have a few extra stones on the shelf. They will go bad and can even break when dropped on a hard surface. When you need them, there is NO substitute. 

Water pumps of all different sizes can be purchased online, from aquarium stores, and sometimes from your local hardware store. Flow rates and duty time (how long an electronic device can run before needing a break to cool down) can be an issue. If we go with hydroponic or aquarium-style pumps, we know they are rated for continuous use. Water pumps are another piece of equipment I highly recommend you keep a spare on the shelf. If the pump goes out, you're back to hand watering. I have made a lot of things work, but you can not compete with a water pump.

Water Filtration in Hydroponics Systems

Water filtration is vital in hydro systems as the water in your system is carrying all of the nutrition for the plants, and any dissolved solids are going to take up the carrying capacity of your water.

For example, if we are starting out with water at a baseline TDS of 500 PPM, we can only add salts (fertilizer) to the point the plants can use. If we overdo it, we will burn the plants. For this example, we are shooting for a TDS of 1500 ppm. If we already have 500 PPM of salts, we can only add 1000 PPM of fertilizer to reach our desired ppm. If we use RO water, we start at 0 PPM and can add 1500 PPM of exactly what our plants are calling for at their current stage of growth! That is a huge advantage, considering most water with high solids is not carrying what our plants desire but locking up the nutrients we have paid to add. RO will save you money, provide better yields, and allow you to tailor your nutrient solution to the plants you are growing.

Water Quality Monitoring Equipment

The two water meters I recommend having are pH & PPM meters. I would recommend spending a little more than you want on these tools. I have never regretted buying the meter one step above what I deemed acceptable. I am not going to name names, but several brands are top of the line. Make sure to get a calibration solution, cleaning solution, and storage solution (some cleaning solution can be used as storage solutions, but CHECK THE LABEL!) 

These meters tell you everything about the new freshwater coming into your system. They tell you how much fertilizer to add and how available the nutrients are for your plants. These meters are the heart of your operation, maintain them, and you will be able to rely on them for years to come. Abuse them, and you will be wasting nutrients or wondering why your harvests are shrinking and without flavor.

How do you build a hydroponic system?

I would recommend buying your first system, at the very least. The amount of accessories invented, redesigned, and improved in the last 15 years of hydroponics is absolutely stunning, making your options endless. One of the other reasons I suggest purchasing your initial system is the fact that not everything you are going to find at the hardware store is going to be food-safe (rated for potable water in hardware store speak).

This brings up a lot of debate among experienced hydroponic producers and manufacturers as well. It would be better then, as a novice, to be focused on the daily operations of running and maintaining a hydroponic system instead of engineering it. 

When you have the experience and are ready to set something up specifically for your space or crop, it may be wise to talk with a hydroponic company about a system design. Many companies have systems designed for a specific footprint. Some are modular and able to be moved if you rent or lease. 

How To Grow Hydroponics Plants - Best Practices, Tips, & More!

Using hydroponic plant nutrients these days is easy and accessible. There are so many brands carrying a “complete” nutrient line it can really get overwhelming. They are all going to have a fairly common one or two-part “base.” Some nutrients cannot be stored together, or they will lose their positive qualities through reactions with other nutrients. This leads companies to usually have a two or three-part “base” formula to make a complete general purpose nutrient solution. 

Beyond the basic nutrient duo or trio, there are companies offering up to 12+ other additives and supplements. There are some high-value crops that arguably could use most of these additions, but even that is a source of major debate among growers of high-value crops. Begin with a reputable brand of nutrients. I recommend opting for their fundamental one or two-part fertilizer, along with a carbohydrate and a micronutrient. It's crucial to note that certain chemicals should not be stored together, as their positive qualities may degrade.

Cleaning and Maintenance in Hydroponics

Cleaning and maintaining your hydroponic system are vital operations to ensure you can remain productive and produce the cleanest produce that you can. I recommend any system get a flush of clean water with some hydrogen peroxide every week. Hydrogen peroxide is a hydroponic grower's best friend! It is a wonderful cleaner and breaks down to pure water and oxygen! 

The maintenance points should be accessible while going through your cleaning operations (pumps, filters, inlets, outlets, etc.) and should be designed to be replaced or removed for maintenance so as not to cause a total shutdown of your system in an emergency, let alone routine maintenance. 

Final thoughts on hydroponics 101

Keep it Simple, Keep it CLEAN! If it is easy to be meticulous, we are a lot more likely to do it. Through experience, conscious planning, and thorough cleaning, hydroponics can be extremely rewarding, especially when it's -30℉ and you are snacking on cherry tomatoes! 

If you want to learn more about hydroponics check out our video series here. The USDA also has many helpful resources on their Hydroponics Page.

By Andy Russo

Glossary of Hydroponic Terms

pH - The measure of how acid or alkaline our water is. This is very important for hydroponics because our pH is adjusted by the flower, and nutrient availability for plants to take in those nutrients affected by pH!

PPM - Parts Per Million or 1 part in one million, also translates to 1 milligram per liter. 

Total dissolved solids (TDS) - this is simply a measure of all of the dissolved particles in a liquid. TDS is generally read in PPM or EC

Nutrient Solution - the mixture of clean water, nutrients and minerals you are using to nourish and hydrate your plants as their sole source of nourishment.

Reverse Osmosis (RO) - water filtration that requires a high pressure to force water molecules through a membrane that removes up to 99.9% of all contaminants. 

Reservoir - The large container that stores the nutrient solution when there is not an irrigation event.

Grow Room - any room or space that is being used to grow plants