The Ultimate Guide to Hydroponics

Hydroponics isn’t a new method of farming.

The Hanging Gardens of Babylon, which were supposedly built around 600 BC, are thought to have operated with some sort of water-based soil-less system.

Plus, gardens that grew on top of water without soil existed in China and Mexico between the 10th and 13th centuries AD!

Today, hydroponic farming is gaining popularity as a sustainable alternative to soil farming.

It’s getting so big, the market’s global worth is predicted to grow to $16 billion by 2025.

We put together this MASSIVE hydroponics guide, so you can learn everything you need to know to get started.

In this article, you’ll learn about hydroponic basics, benefits, nutrient solutions, growing media, system types, costs, and how to do it yourself!

You can read it all the way through. Or you can use the table of contents to find the parts you’re the most interested in.

Don’t forget that you can always save it to come back to later too!

First, let’s look at the most basic aspects of hydroponics.

The Basics of Hydroponics

Hydroponics is a farming method that uses nutrient rich water, rather than soil to grow plants.

The word hydroponics is a combination of two Greek words, literally translating to “water labor.”

These systems are commonly used today for indoor and vertical farming, because they don’t require things like fields, soil, or authentic sunlight.

That’s because farmers who use hydroponic systems to grow crops, rely on a nutrient solution and growing medium, rather than fertilizer and soil.

The goal of hydroponic systems is to make it as easy as possible for plant roots to soak up the water, oxygen, and nutrients needed for strong, healthy growth.

There are many different ways, this goal is accomplished.

Some systems deliver only a little bit of nutrient water to the plants at a time.

Others have the plants growing on top of a large reservoir of water.

However it works, all hydroponic systems use nutrient solutions to cultivate crops. 

The nutrient solution is made up of all of the nutrients a plant needs to grow.

This solution is added to water, which is then delivered to the plants to replace the food they would’ve gotten from soil instead.

In soil, plant roots have to spread out in search of nutrients.

But in hydroponics, the nutrients are given right to them.

Additionally, many hydroponic systems use a growing medium to support the stem like soil would.

The medium is an inert material so it can’t grow the plants on its own.

We’ll go more into depth on nutrient solutions, growing media and types of systems later.

For now, we’ll take a look at some of the many benefits of hydroponics.

Benefits of Hydroponics

Hydroponic systems have a lot of great benefits!

Many stem from the fact that soil is not involved.

Other benefits have to do with how hydroponic systems operate in general.

Hydroponics Saves Space

Plants grown in soil, need to spread their roots in order to find water and all the nutrients they need to survive.

This means they must be planted a certain distance apart from each other.

In hydroponic systems, roots don’t need to spread out because water and nutrients are delivered right to them.

Instead, the roots can focus on growing down, long and healthy.

As a result, hydroponic systems can grow more plants in the same amount of space as soil-based systems.

Water Conservation

Did you know field farms account for 80% of the United States’ water use?

Field farming uses so much water because it loses a lot of it!

In fields, water evaporates, rolls away, and puddles, making much of it unusable.

That’s a lot of waste!

Hydroponic systems use about 90% less water because it’s delivered in a controlled system.

Plus, some hydroponic setups reuse water, reducing consumption even more!

Fewer Chemicals

While hydroponic systems don’t eradicate pest issues, it does lower the potential of this happening.

As a result, insecticides and herbicides aren’t needed.

Hydroponic systems are highly controlled so there’s no risk of weeds taking over your garden.

So, there’s no need for herbicides.

Plus, because many hydroponic systems are often indoors, insects can’t infiltrate them as easily.

So, insecticides aren’t necessary either.

Faster Growth

Did you know plants grown in hydroponic systems, grow 30% to 50% faster than those grown in soil?

Crops grow faster in hydroponic systems because they receive an ideal amount of nutrients.

Plus, if they’re grown indoors, they have fewer environmental causes of stress, like extreme weather.

Some species of crops grow faster than others.

For example, leafy greens, like herbs, and thirsty fruits, like tomatoes, tend to grow the fastest in hydroponic systems.

Nutrient Control

Hydroponic systems feed plants a nutrient solution mixed with water, giving the farmer better control over what nutrients their crops soak up.

Too much farming in the same plot of soil can deplete the soil of its natural nutrients.

So, farmers have to use fertilizers to help.

But in hydroponics, the plants are already receiving all the help they need and the right amount of it.

Do your research and make the right measurements, and the crops will have everything they need to survive just from their water.

Grow Indoors

Another benefit of hydroponic farming is that it’s easy to do indoors.

Growing indoors, has benefits like the ability to grow year-round, temperature and climate control, and fewer pests.

Hydroponic systems are usually implemented indoors, because of the environmental control it offers.

With near perfect growing conditions and protection from the elements, plants grow stronger and faster.

Healthier Plants

In hydroponic farming, plants grow healthier than in soil.

For one thing, soil-borne diseases aren’t an issue in hydroponics.

This is because there is no soil for those diseases to fester and spread in.

Plus, plants don’t have to spread their roots out in search of nutrients.

As a result, they get to focus more energy on growing.

No Soil Erosion

Field agricultural practices have eroded half of the soil on Earth in the last 150 years.

This has decreased the availability of farmable land.

Hydroponic systems don’t use soil.

No soil means no soil erosion.

It’s that simple.

Now that you know all of the wonderful benefits hydroponics has to offer, we can look closer at how it works!

Nutrient Solutions for Hydroponics

The nutrient solution is one of the most important parts of a hydroponic system.

It is highly concentrated with essential minerals and vitamins.

Usually, the nutrient solution comes as a liquid or powder, in order to mix easily with water.

The solution is a substitute for soil, providing all the same nutrients in a more direct and potent way.

As a result, plants grow stronger and faster.

In soil, roots need to spread out to survive, but not in hydroponics.

Hydroponic systems deliver nutrients straight to the roots, letting the plant focus on growing strong and healthy, rather than surviving.

Without nutrients, cultivating crops is impossible.

In this section, you’ll learn all about nutrient solution.

Nutrient Solution Basics

Nutrient solution is full of all the essential elements plants need to survive.

But finding and balancing the right nutrients can be tricky for beginner hydroponic farmers.

Farmers can purchase premade solution or make their own.

But premade solutions are more common for low-scale farming.

Solutions from the store typically come in liquid form for easy blending with water.

It’s important to consider the proper proportion of nutrients to water when mixing.

Over or under saturating your water is detrimental to plant health.

You can find the right proportions for your solution on the bottle, or by contacting the manufacturer.

Younger plants require less nutrients than mature plants, so it’s important to adjust your solution as your plants grow.

It’s also important to track the pH level and temperature of the nutrient water.

The pH levels of your water will influence the solubility of the nutrients.

If the pH is too high, or too low, your plants won’t be able to absorb all of the nutrients that they need.

Be sure to research the optimal pH for your specific crops.

In general, the range that works best for most crops is 5.8 to 6.3.

The temperature of the water should remain consistent as well!

If your water is too hot or cold, your crops won’t be happy.

High temperatures cause heat stress in plants, leading to wilting and root death.

Conversely, low temperatures cause slow growth.

As such, be sure to keep water in the 70-degree range—no lower than 60 degrees and no higher than 80 degrees.

Also, keep in mind the quality of the water you’re using.

Raw water may have minerals that are harmful to plants, like chlorine.

Therefore, before mixing water and nutrient solution, be sure to test and pretreat your water, if needed.

Next, we’ll look at some of the essential nutrients that plants need.

Macro & Micro-Nutrients

The amount of nutrients a plant needs varies by species.

But there are some nutrients all plants need to survive.

These nutrients are broken into two categories: Macronutrients and micronutrients.

Both categories are essential for plant survival.

But micronutrients are needed in smaller quantities.

Macronutrients include:

  • Nitrogen: for converting light into energy
  • Potassium: for regulating enzymes and growing
  • Phosphorus: for flower, fruit, seed and root development
  • Calcium: for forming cells
  • Magnesium: for creating oxygen during photosynthesis
  • Sulfur: for producing amino acids.

Micronutrients include:

  • Boron: for strong roots
  • Copper: for resisting toxic minerals and transferring electrons
  • Iron: for creating chlorophyll
  • Manganese: for evolving oxygen during photosynthesis
  • Zinc: for promoting growth.

All solutions should have these nutrients.

Different plants need different ratios of the nutrients.

So, be sure to know what ratio will work best for the crops you’re intending to grow.

Most farmers purchase their nutrient solution, but you can make it at home as well.

Premade vs Homemade

Nutrient solution can be purchased premade or made at home.

Premade solutions are easier, especially for novice farmers.

But homemade solution offers the ability to tailor nutrients to your specific crops.

Premade nutrient solution usually comes with two or three parts.

A solution that comes with two parts is typically separated.

It will have macronutrients in one container and micronutrients in the other.

This is because some nutrients are incompatible in their concentrated forms.

As a result, they must be kept apart from each other until they’re mixed with water.

Generally, nutrient solutions call for mixing 3.5 milliliters of each concentrate per liter of water.

But you should always refer to the manufacturer’s recommendations before mixing.

There are plenty of DIY options for nutrient solutions.

These range from soaked compost to mixing individual nutrients together.

Homemade nutrient solutions are riskier, especially for newer hydroponic farmers, because it’s subject to more human error.

If you’re interested in making nutrient solution at home, do extensive research to be sure that you add the proper amount of nutrients.

Whether you use homemade or premade solution, be sure to check the pH levels and balance as needed after mixing with water.

Now that you know all about nutrient solution, we can move on to growing media.

Growing Media for Hydroponics

While growing media is similar to soil, nutrient solution is its true substitute.

Why?

Well, growing media might act like soil by supporting the plant’s roots and stem, but it can’t grow the plants without nutrient solution.

Conversely, nutrient solution can grow crops without a growing medium.

As a result, not all hydroponic systems will use a growing medium.

But most do, which is why we’re going to take a close look at it in this section.

Common Qualities

Growing media need to have a few key qualities in order to work well.

For one thing, the medium can’t decay or break down quickly.

It also needs to be able to hold moisture well, so that the plants need less frequent watering.

But it also needs to be able to hold enough oxygen to avoid suffocating the crops.

To meet these two qualities, growing media are often porous.

Depending on the growing media you use, you may need a special medium for starting seeds.

Seed starters will help you seamlessly plant your seeds and later transplant the crops into your hydroponic system.

When choosing a medium, you’ll want to keep three acronyms in mind: WHC, AFP, and CEC.

Water Holding Capacity (WHC)

WHC stands for Water Holding Capacity, which indicates how well the medium holds water.

Knowing the WHC of your growing medium is important, because some hydroponic systems will be more compatible with lower WHCs.

Others will be more compatible with higher ones.

For example, wick systems benefit from high WHC mediums, like coco coir, because it keeps nutrients easily accessible without overwatering.

Conversely, nutrient film technique (NFT) systems benefit from lower WHC mediums, like clay pebbles, because the plant roots are constantly exposed to nutrient solution.

As a result, they use a medium for support reasons more than saturation.

Air Filled Porosity (AFP)

AFP means Air Filled Porosity.

It’s the proportion of volume that is filled with air.

A low AFP means the medium can’t provide the plants with oxygen very well.

Low AFPs puts crops at risk for drowning and rotting.

That’s why higher AFP ratings are more desirable.

Cation Exchange Capacity (CEC)

Finally, CEC, or Cation Exchange Capacity, refers to the medium’s ability to capture positive ions, like potassium, calcium, and magnesium.

In hydroponic systems, having a low CEC, like rockwool, allows you to have better control over the nutrients your plants receive.

Growing mediums with a higher CEC, like coco coir, may require specially tailored nutrient solution, in order to achieve the right balance.

With those acronyms in mind, let’s move on to types of growing media.

Four of the most popular growing media for hydroponic systems are rockwool, lightweight expanded clay aggregate, coco coir, and perlite.

Rockwool

Rockwool, also known as stonewool, is a porous material made of spun basalt rock fibers.

This growing medium is extremely popular due to its high WHC and low CEC.

It saturates easily, but still drains well, making it a great choice for ebb and flow systems.

Unfortunately, rockwool is not biodegradable so eco-conscious farmers might hesitate.

Plus, it’s not pH neutral, so that needs to be corrected before use.

Otherwise, its naturally high pH will make it inhabitable for plants.

Lightweight Expanded Clay Aggregate

Lightweight Expanded Clay Aggregate, also known as clay pebbles, are round pieces of heat-expanded clay.

Clay pebbles have a low CEC and WHC and a high AFP.

As a result, it’s difficult to over-water and easy to provide enough oxygen for plants.

It’s also reusable!

On the downside, clay pebbles are heavy and may drain too quickly for some systems.

As a result, this medium works best for deep water culture (DWC) systems, which keeps plant roots constantly exposed to water.

Coco Coir

Coco coir is an organic, biodegradable growing medium made from shredding the inner pith of coconut husks.

On the upside, coco coir is a sustainable choice.

This is because it gives purpose to a coconut product that’s usually thrown away.

It also traps oxygen fairly well and feels similar to potting soil.

Coconut fiber is somewhere in the middle, when it comes to CEC and AFP, but it has a high WHC.

Nutrient solution made specifically to balance out its CEC is recommended.

And farmers should keep an eye out for signs of rot as it’s prone to overwatering.

These aspects make it especially suitable for drip systems where water intake is highly controlled.

Perlite

Perlite is a volcanic rock and can be added to other growing mediums or used on its own.

Fans of perlite like that it’s lightweight and has a very low CEC and high AFP.

So, it’s easy to control nutrients with.

It also absorbs water fairly easily, but not so well that there’s a high risk of overwatering.

However, perlite floats in water.

As a result, it’s unsuitable for plant support, in systems that submerge the growing medium, such as ebb and flow.

Therefore, this growing medium works best for wick systems.

Next, you’ll learn about some different hydroponic systems and how they work.

How Different Hydroponic Systems Work

Different types of hydroponic systems use different processes to grow crops.

These processes vary in many ways, but there are four classifications to describe them.

Classifications

The four major classifications that describe hydroponics systems are passive, active, recovery, and non-recovery.

All four of the classifications distinguish how water moves through the system.

In passive systems, the water either doesn’t move at all, or funnels and gravity work to move the water.

Often, passive systems rely on capillary action.

Capillary action takes place, when the growing medium, or a wick soaks up the nutrient solution, moving it upward toward the plant roots. 

In active systems, the water moves with the help of water pumps and tubes.

Passive systems are easy for beginners, but don’t offer nearly as much control as active systems.

The other two classifications are recovery or non-recovery, also known as recirculating and non-recirculating.

In recovery systems, the nutrient water is circulated and then recaptured.

This allows the system to reuse the water.

Non-recovery systems don’t recapture the water, so it can’t be used again.

Recovery hydroponic systems save more water than non-recovery systems, because the water doesn’t have to be fresh every time.

Next, you’ll learn about five systems and how they work.

Examples of Systems

Three of the most basic hydroponic techniques include the wick, ebb and flow, and deep water culture systems.

Wick

Wick systems are passive and non-recovery.

In this process, plants are grown in a container above a reservoir of nutrient-rich water.

Wicks, like you’d use for a candle, connect the reservoir to the growing medium.

The wicks soak up the water from the reservoir, using capillary action, to deliver the water to the plants’ roots.

Wick systems are very basic.

As a result, they can’t provide a lot of oxygen to the plants, which is essential for fast, healthy growth.

Another popular basic system is the ebb and flow method.

Ebb and Flow

Ebb and flow is an active recovery system.

In this method, the plants sit in a shallow tray and the nutrient solution is pumped in to flood it.

After a certain amount of time, the water is drained back into its reservoir to wait for the next flood.

This system is popular because it requires little maintenance and it’s highly effective.

That’s why it’s the basis for several other more complicated systems.

But it’s a little harder for beginners because it requires automated water pumps to work properly.

Deep Water Culture

The deep-water culture (DWC) system is another passive, non-recovery system.

In DWC, the plants sit on top of a deep container of nutrient water.

As the plants grow, their roots extend downward and drink more and more of the water.

In this system, the roots of your crops are submerged in water 24/7.

As a result, it’s essential to include an air pump and air stone in the reservoir to maintain proper oxygen levels.

These are just a few of the basic systems available for hydroponic farmers.

Some higher tech systems, often borrow and expand on aspects of these basic ones.

For example, nutrient film technique and deep flow technique hydroponics, both borrow from the ebb and flow method.

Nutrient Film Technique

The nutrient film technique (NFT) is similar to ebb and flow.

For one thing, both are active recovery systems.

Plus, in both, a pump delivers the nutrient water to a tray of plants and recycles the unused water.

But in ebb and flow, the water is released and recaptured in intervals.

In NFT systems, the water is constantly flowing through the trays.

NFT systems use water pumps to run a small amount of water through the system.

The plants sit on top of the trays with their roots hanging down and the water passes through the roots.

Because it’s such a small amount of water, it’s more like a film than a flood.

The trays sit at an angle to help the water reach the other side, where it drains out to reenter the reservoir.

Only a little bit of water is released through the trays at a time, to avoid drowning and rot.

Additionally, shorter trays are preferred over longer ones, since shorter trays help ensure even distribution of the nutrients.

This is because the plants at the far end, can receive the same amount of nutrients, as the ones at the beginning.

Deep Flow Technique

Deep flow technique (DFT) borrows elements from ebb and flow and DWC systems.

DFT hydroponic systems keep plant roots constantly submerged in water, like in DWC.

But it also floods and drains the water like in ebb and flow.

In DFT systems, aerated nutrient water from a reservoir is pumped up into one side of a tray.

The plants sit on top of the tray with their roots hanging inside.

As the water is pumped in, it circulates around, delivering nutrients to the plants’ roots.

On the opposite end of the tray, a drain brings the used water back down to the reservoir.

This might sound similar to the NFT system.

But it’s important to note that DFT passes significantly more water through the trays at a time.

As a result, the trays don’t have to sit at an angle, to help move the water to the other end.

Plus, one concern with an NFT system, is how much it relies on the water pump.

Because only a tiny bit of water passes through at a time, if the water pump shuts off or breaks, the plants will not receive any nutrient water and will die.

Since DFT systems hold more water at a time, there is enough sitting water in the trays to keep the plants alive, if a problem with the pump occurs.

As you can see, even the more complicated systems use the same basics as the simpler ones.

Now that you have an idea of what goes into making a hydroponic system work, we can move onto price.

How Much Does a Hydroponic System Cost?

A lot goes into how much a hydroponic system costs.

Some people use hydroponic farming as a gateway to start a farm business, while others use it to feed their household with fresh, home-grown produce.

In this section, you’ll learn about the factors that influence the cost of hydroponics.

There are three tiers of hydroponic systems:

  • Low-tech
  • Middle-tech
  • High-tech

Low-Tech Systems

Low-tech hydroponic systems include budget units or DIY constructions.

You can purchase a low-tech hydroponic system for about $50 to $200.

Construction costs for a small DIY project are about the same.

Middle-Tech Systems

Middle-tech hydroponic systems are purchasable and can be installed indoors, or outdoors.

They typically come with lighting and some higher-end technology, like water flow control.

These systems range from $300 to a couple thousand dollars, depending on size and features.

High-Tech Systems

High-tech hydroponic systems, include complete system control, like our Pure Greens container farms.

These are best for farmers who are aiming to produce a high volume of crops for profit.

High-tech hydroponic systems can be tens of thousands of dollars. 

Aside from technology, there are four main factors that will influence price estimates:

  • Type
  • Size
  • Control
  • Additional materials

Type of System

Different types of hydroponic systems will require different components and maintenance.

For example, if you wanted to build a nutrient film technique (NFT) system you would need a water pump.

But for the wick technique, you wouldn’t.

Additionally, your reoccurring costs can vary.

For instance, whether your system is recovery, or nonrecovery will affect your monthly water bills.

Size of System

The size of your system plays a huge role in determining how much hydroponic systems cost.

If you’re farming as a hobby, a smaller cheaper system is adequate.

If you’re trying to produce a high volume, you’ll need a larger system, which will be more expensive.

Additionally, the desired type of crop will influence the size of your system.

Some are only compatible with one type of crop per system.

Usually, these are ones where you can’t tailor the nutrient solution to individual crops.

So, if you want to diversify your selection, you’ll have to have multiple systems.

You’ll also have to consider whether you have the space for a vertical or horizontal system.

Vertical systems can produce more per square foot, than horizontal systems.

But they may be more expensive, as they’re typically considered high-tech.

System Control

The level of control, you have over your hydroponic system, will also influence the price.

More control over aspects like temperature, water pressure, and humidity levels will bring the cost up in several ways.

First, if you want to incorporate controlled environment agriculture technology into your hydroponic system, the amount of money you spend on energy each month will increase.

Additionally, you will have to spend more money on maintenance as high-tech systems may require special expertise and parts to fix if something goes wrong.

Whereas low-tech systems can be easily replaced if needed.

But having little environmental control has its own costs.

If your hydroponic system is outside, there’s a greater risk of losing crops to weather, infestations, and disease.

Replacing damaged equipment and plants costs money, not to mention lost profits from dead crops.

Additional Materials

Any additional materials you may need for your hydroponic system, will be extra on top of the system itself.

DIY systems lump these costs together, so you’d just have to keep in mind reoccurring expenses like nutrient solution and growing media.

Pre-built hydroponic systems, however, may require additional labor costs for installation or may not come ready for immediate use.

For example, even if the hydroponic system has everything it needs to function properly, you still might have to purchase growing mediums, nutrient solution, a pH meter, and lighting separately to actually start growing plants.

Lighting itself can be $20 to hundreds of dollars depending on size, quality, and quantity.

Additionally, you’ll have to factor in whether you already have the space for a hydroponic system.

If not, you may need to purchase, or rent a new property for your farm.

Once you’ve taken all of these factors into consideration, you can calculate how much a hydroponic system will cost for your farm.

In the next section, you’ll learn how to make two cheap and easy hydroponic systems yourself!

DIY Hydroponics

You can do it yourself (DIY) when it comes to hydroponics.

The internet is full of videos and articles directing new hydro farmers on how they can get started.

But there’s so many different options!

In this section, you’ll learn how to DIY two super simple systems for hydroponics.

There are a few basic materials you’ll need for your setup, regardless of which method you choose.

You’ll need a sprouted plant, a growing medium, nutrient solution, and net cups.

Start with a sprouted plant, because both systems need developed roots in order to work well.

You can use any growing medium.

But rockwool and clay pebbles are recommended for these two systems.

You can purchase net cups online, or from a gardening store. Or you can DIY it by cutting slits and holes in the bottom of plastic, disposable cups.

Just make sure that it will fit the top of your chosen system snugly.

Soda Bottle Wick System

A wick system grows plants above a reservoir of water.

The wick connects the two and delivers water to the plant.

To create your own, you need a 12-inch cotton string and a clean, empty liter soda bottle.

Cut off the top of the bottle about 8 inches from the bottom.

Drill or puncture a hole in the center of the bottle cap.

Then, screw it on tightly.

Place the top of the soda bottle inside the other half, so that the cap is pointing down.

Thread the string through the hole in the cap.

Half of the string should be in the bottom container and the other half should be in the top container.

Pour enough nutrient water into the bottom container to cover the string.

Fill the top container with the growing medium and transplant a sprouted plant into it.

The wick will draw up the water into the growing medium and the plants will absorb its nutrients.

This system keeps plants watered without drowning them.

Thirstier plants like tomatoes, aren’t well suited to this type of system.

But leafy herbs will thrive.

The Kratky Method of Hydroponics

The Kratky method resembles a deep-water culture system.

In both, the plants rest on top of a container of water with their roots constantly submerged.

However, the Kratky method does not need an air pump to oxygenate the water.

Instead, plants receive oxygen from the little space between their netting and the surface of the water.

As the roots grow longer and suck up more water, the water levels decrease, and oxygen is released.

Large mason jars, buckets, and tubs are all possible options for creating a Kratky hydroponic system.

When using a bucket or tub, drill holes just big enough for the nets in the lids.

For mason jars, simply be sure to pick nets that fit snuggly in the opening.

Place the net cup in the container’s opening.

Fill it with growing medium and transplant the sprouted plant into the net.

Combine the nutrient solution and water.

Fill the container until the water level is just touching the bottom of the net cup.

Don’t refill the container, until your plants absorb all of the water or are ready for harvest.

Be sure to leave room at the top for oxygen when refilling.

When light hits the water through the clear container, it can cause algae to grow.

Avoid clear containers or cover the outside of the container with a thick material to avoid this problem.

Leafy greens, like lettuce and herbs, will grow the best in a Kratky system.

Congratulations!

You now know enough about hydroponics to get started on your own.

Since you’ve made it to this point, you’re clearly interested in learning about hydroponics.

We’ve made a ton of articles and videos covering even more aspects of this topic, plus many more!

Visit our website puregreensaz.com or call 602-753-3469 to learn more about how you can start farming.