Hydroponics vs. Soil

hydroponics vs soil

Hydroponics can seem like a strange & futuristic way of gardening. Don’t let the oddities scare you--hydroponics has shown some great results that may just make it worth the effort.

Hydroponics--growing plants without soil--versus soil each have their pros & cons. Generally, hydroponics is more expensive to start up, but has faster & higher yields, and less likelihood of disease. However, results depend on the plants grown, and hydroponic system used.

Whether you already have a thriving garden and are wanting to make a change, or you’re a novice looking to start growing plants with a certain flair, starting up a hydroponic garden doesn’t have to be a huge leap. Let's dig in (sorry, bad pun) & take a look at the different hydroponic systems & options, along with the pros & cons so you can decide for yourself.

growing in soil

Growing with Soil

When starting a garden or setting up a greenhouse, soil is one of the first items on the shopping list.

Plants rely on soil for structural stability, nutrients like nitrogen, potassium, and phosphorous, and healthy soil even protects plant from diseases and pests.

Soil is a lot more than just dirt--it provides the physical substrate for plant roots to grow, oxygen for plants, and a rich community of microorganisms that provide plants with nutrients.

Growing with Hydroponics

At first, hydroponics might seem to be a pretty odd technique for growing crops, considering that it takes the one thing that just about every plant needs--soil--and throws it out the window. And while soil certainly does provide benefits, the truth is that it’s less of a necessity and more of a convenient way of getting what the plants really wanted in the first place: nutrients.

So, why not just cut out the middleman?

In a hydroponic system, the plants grow directly in a water-based nutrient solution or some kind of growing medium rather than soil.

Not specific enough? It’s for good reason. There are lots of different methods that fall under the category of hydroponics, each with a new, special take on things.

Types of Hydroponics

OK, let's dive in. Here are the main types of hydroponic systems that we'll dig into:

  • deep water culture
  • wick system
  • nutrient film technique
  • ebb & flow
  • drip hydroponics
  • aeroponics

Hydroponic system

pros

Cons

Deep water culture

  • Simple
  • Lower setup costs
  • Nutrient solution must be changed often
  •  Not suited to all types of plants

Wick

  • Simple
  • Requires No Electricity
  • Suitable for smaller, low-maintenance plants

Nutrient film technique

  • Plants grow faster
  • No need for a timer
  • Pumps prone to clogging
  • Potential for quick die-off if pump clogs & you don't monitor the system

Ebb & flow

  • Low maintenance
  • Nutrient mixture can be recycled
  • More complicated
  • Best for plants that can handle dryness
  • Pumps prone to clogging

Drip

  • More control
  • Ability to tailor nutrients for each plant
  • Requires timer
  • More complicated

Aeroponics

  • Most versatile
  • Uses less water
  • Allows for fast plant growth
  • Suitable for wide variety of plants
  • Most expensive
  • Mist nozzles can clog

Deep Water Culture

The deep water culture (DWC) system is the most conceptionally simple. In the other systems, the plants are kept separate from the nutrient solution; each variation of the hydroponic system is based on how the plants & nutrients connect.

In a DWC system, though, the plants are submerged directly into the reservoir of nutrients.

Here’s the design:

  • A container is filled most of the way with the plants’ nutrient solution.
  • The plants float on top of the liquid, kept in a polystyrene plant tray which allows the roots to be suspended and constantly bathed in the nutrient solution.

To keep the roots from rotting in this continual bath, you need an aquarium pump, or an air stone bubbler, in the tank.

This way, the plants are always getting to soak up nutrients without having to suffocate.

Even with the air being oxygenated, this excess of water isn’t the best option for every type of plant. But for plants like lettuce, it's a great environment.

A DWC system is a great introduction to hydroponics because of the simplicity of design and the relatively cheap set-up costs. However, the nutrient solution must be changed more often than in other systems, and the types of plants that work best with DWC is more limited.

Wick System

Like the DWC set-up, the wick system is designed simply, but has different pros & cons.

With a wick system, the plants are kept in a medium like vermiculite or perlite--something that won’t absorb too much of the nutrients, which would defeat the purpose. The plants don’t come in contact directly with the nutrient solution, which is kept in its own container, but are fed through--you guessed it--a wick.

The wick can be nylon or cotton--it doesn’t matter what exactly is used as the wick, so long as it’s absorbent.

The great part about this system is that it requires no electricity, making it a very low-cost option. The wick feeds the plants like a straw and you’d rarely need to check in on them.

Of course, it’s not all sunshine and rainbows.

It takes time for the nutrients to climb up the wick and feed the plants. This limited food availability makes it suitable for smaller, low-maintenance plants like herbs, and not ideal for fruit-bearing ones.

Nutrient Film Technique

This next system is a bit more…extreme. But, hey, it works.

The Nutrient Film Technique (NFT) works by putting the plants in a grow tray like what would be used for the deep water culture (DWC). The tray is positioned above the reservoir tank (which is filled with the nutrient solution) and slightly tilted, so it’s at an angle.

A pump transports the nutrient solution up and into the grow tray, where it flows continuously over the exposed, hanging roots of the plants.

With the grow tray being set at an angle, gravity forces the excess nutrient solution to fall back into the reservoir below. The amount of nutrient solution touching the roots is scarce, though constant. This keeps the plants from being overfed.

This cycle created by a nutrient pump and gravity ensures that little upkeep is necessary. The only other crucial aspect to this system is an air stone/air pump placed in the reservoir to provide the water with oxygen.

There are a lot of benefits to this system. It’s a great balance between too much nutrient solution, like you might get with the DWC, and too little, like you might get with the wick system.

Plants in this system also tend to grow faster, likely because of the increased oxygen, and no grow medium is required. And, since it’s set up to flow constantly, there’s no need for a timer, like in the other systems we’re about to look at.

The need for (and cost of) a nutrient pump and electricity makes this technique more expensive than others.

And, unfortunately, pumps are known to clog, making the NFT something of a high-risk, high-reward investment. For example, if you forget to check the system--and the pump clogs--your plants could croak really fast.

Ebb & Flow

The ebb and flow hydroponic system is more complicated, which is only fair because it has a cooler name.

In a large grow tray, plants are kept in a medium like vermiculite, perlite, or even coconut coir, and placed above the nutrient reservoir.

Unlike the NFT, the grow tray isn’t at an incline, and therefore must have holes in the bottom to allow for drainage.

This system also requires a timer. When an ebb and flow system is set up, the schedule it operates on will need to be made, too. The idea is to have the nutrient pump fill the grow tray for a certain amount of time--long enough that the water level reaches the roots in the medium.

At that point, the pump will shut off and the nutrient solution will begin to trickle back into the reservoir beneath it.

The timer will ensure that this flood and drain process--which is another name for the system--will continue regularly.

Generally, this system works best for plants that can handle dryness for some time. But, since the timer has to be set manually, there’s no reason that you couldn’t shorten/lengthen the intervals in between watering to fit the needs of the crop.

The additional requirements of a timer and a medium, along with the chance of the pump getting clogged, are the disadvantages of this system.

On the other hand, there would be good air flow, the nutrient mixture would be recycled, and the timer does all the work.

drip hydroponics system

Drip Hydroponics

The drip method of hydroponics is a lot like the ebb and flow system, but, as the name implies, at a more controlled rate.

Again, the grow tray with the plants and a medium sits above the nutrient reservoir. Instead of flooding the medium with nutrients, a drip manifold deposits the solution at the base of each plant with drip lines, like arms reaching down.

This system is often set up with a timer like in the ebb and flow design, though it isn’t necessary if the drip lines include emitters, which control the speed that the water comes out.

This ability to manipulate how much water reaches each individual plant in a single grow tray is a huge advantage of drip hydroponics, making it much more versatile than other systems.

Aeroponics

Last but not least: aeroponics. This method is by far the strangest, most advanced, and most adaptable.

Plants hang freely from the grow tray without a medium so that the roots are exposed. Unlike every other system of hydroponics, the nutrient solution isn’t poured, dripped, or sucked upwards--it’s sprayed as a mist.

The water pressure is built up inside the pump, then mist nozzles release the spray over the plant’s root system like your face when you wait in line at the water park.

Refreshing.

Comparing this method to the others, you’ll notice that aeroponics seems to use less water. Because of this, the plants must be sprayed frequently, which requires a timer.

As you can imagine from the necessity of the mist nozzles, it isn’t the most economical choice, since the mist nozzles can clog.

However, the nutrient solution is constantly recycled and the turning of water into mist provides the solution with much more oxygen than the others, which might allow certain crops to grow quicker.

Plus, since you get to control both the amount of water sprayed and how often.

As a result, aeroponics works well with a huge variety of plants.

Getting Started

Hydroponics

Figuring out where to begin setting up a hydroponic garden easily becomes overwhelming.

Start by deciding which plants you want to grow, then let the needs of that plant govern what kind of system you’ll have.

If you want to start with lettuce, you can go the DWC route. If you want herbs, the wick system would be a good choice.

And, if you already have a regular, soil-based garden, remember that not everything has to, or should be, switched to hydroponics. If you want to make changes, do it in increments to get the hang of it.

Once you know what kind of system you’ll have, the next decision is the big one: establishing a budget.

A large part of how much a hydroponic garden costs to set up depends on the type of system you’ll use. An aeroponic system will always cost more than a deep water culture.

When you have your budget fixed, you can choose between buying each of the necessary pieces separately or altogether in a kit.

For example:

  • A 6-bucket DWC system costs ~$110, not including the nutrient solution, which costs around $20.
  • A 72-hole ebb and flow type of system costs ~$120.
  • A decent aeroponic system will likely cost over $500.
  • The last component you’ll need for any hydroponic system is a pH meter.

Finally, you'll need to set up your system. Choose where to locate the system based on how much sunlight the plant needs and any physical limitations that your system might have. Afterwards, you’re ready to start growing.

Soil

The first step to getting started with a soil-based garden is the same as getting started with hydroponics--decide what you want to grow.

Next, figure out where your garden will be located. Again, the plant really decides this. But you can choose whether you want to grow in a greenhouse or outdoors and how much space it will take up.

After that, you’ll need the actual soil as well as compost. Test the soil in your yard to find out what type it is, or if it’s too dense, dry, loose, etc. Make the necessary changes from there, or buy gardening soil from a local store.

If you’re using a greenhouse, you can start filling pots or growing trays with your soil, and if you’re making a raised bed, fill that with a depth of at least 6 inches of soil. Or, if you’re gardening directly in your yard, make sure that there aren’t any large clumps, rocks, weeds, or too much grass. Add compost.

You’ll also need some tools, like a shovel, rake, hoe, trowel, sears, and possibly more, depending on what kind of garden you’re expecting to have.

Once you have all the supplies, you’re ready to start planting. After planting, add mulch as needed.

To give a price estimate for getting started, we’ll use an 8-foot by 4-foot plot. Assuming that you choose to buy bags of garden soil or potting mix, the total cost will probably be between $150 and $200, if you didn’t have any of the tools either. Add between $100 and $200 to that if you want a raised bed.

That said, there are always ways to cut down on the cost and opt for the DIY approach. Even an 8-foot by 4-foot raised bed could cost less than $50.

Maintenance

Hydroponics 

One of the best qualities of a hydroponic garden is that it’s largely self-sustaining. Either the system is designed to take care of itself, like the wick system, or the timer and pumps do all the work.

Just because your plants are likely doing fine doesn’t mean you shouldn’t check on them regularly, though. It only means that what you should be checking is different.

Every day (or every other day), take a look at the system. If it’s the type that will flood/release water on a schedule, check specifically at one of the times when it’s doing so. Make sure that the pumps aren’t clogged by the nutrients.

During these quick checks, take a moment to examine the health of your plants, looking for any signs of rotting or disease and checking that they’re getting enough sunlight. If the plants are getting too much or not enough water, you’ll want to handle that quickly. Trim any dead or overgrown areas as you find them.

Aside from clogged pumps, the most common problem with hydroponics is the pH. Using paper strips or a testing kit, check the pH once a week to ensure that your plants don’t feel like they’re swimming in bleach. Most plants thrive in a neutral pH.

Lastly, every 2-3 weeks, empty and replace the nutrient solution and clean the pumps. This is the simplest way to prevent clogs.

The maintenance of a hydroponic system is minimal. The system takes care of itself almost all of the time, but when something does go wrong, it needs to be corrected ASAP.

soil

Soil

Maintaining a soil-based garden is straightforward, but work is required more often. Here, you need to remember to water your plants. This should generally be done every day, preferably in the morning so that water isn’t left sitting overnight.

After building your garden up, you’ll need to watch for weeds for some time. Getting rid of them earlier will prevent them from running rampant later.

Like in a hydroponic system, spend some time verifying your plants’ well-being. Cut away the dead or overgrown parts, make sure you’re not overwatering/underwatering, and check that they’re getting the right amount of light.

If you’re growing outdoors, the temperature and humidity are other factors that you will have to protect your plants from.

Also, keep your soil healthy to avoid plant disease and unwanted pests. Disinfect your tools regularly, and ensure that the soil has enough nutrients by adding fertilizer about once a month during your plants’ growing season.

Pros & Cons of Each System

Between hydroponics and soil, both have certain advantages and disadvantages that should be considered before deciding between the two.

Pros of Hydroponics

Contrary to what you might think, hydroponics actually uses less water than a soil-based garden. With soil, much of the water isn’t absorbed by the plant, but evaporates or soaks into the medium. A hydroponic system usually recycles the water, and, in effect, the nutrients.

Another benefit of hydroponics, as previously mentioned, is the minimal amount of maintenance. It only needs a quick, consistent check to make sure everything is running smoothly. There won’t be a ton of weed-picking.

In many cases, people have found that growing with hydroponics is faster and produces higher yields than when growing with soil. This is likely because the roots of the plant don’t have to grow as much in search of nutrients, water, or oxygen, and the effort can be put toward growing elsewhere.

Since hydroponic systems are set up indoors, the plants grown aren’t restricted to their usual growing seasons. These systems can also save a lot of space, especially if made into a vertical or hanging design.

And, without a medium to support the growth of bacteria, hydroponic systems have fewer occasions of plant disease

So, to recap, hydroponics:

  • Uses less water than soil
  • Requires less maintenance
  • Possibly produces higher yields
  • Allows for year-round crop growth
  • Doesn’t take up a lot of space
  • Is less likely to stimulate plant diseases

Cons of Hydroponics

Now for the drawbacks. Hydroponic systems cost a lot to get started. Even simple systems can be expensive, with all the supplies needed.

And, though hydroponics requires less maintenance, it can also be harder to notice when something is going wrong. If there is a problem and it isn’t corrected immediately, you can lose a lot of crops in a short amount of time. You have to keep an eye out.

If you decide on a system that requires electricity, you’ll have to account for the extra cost and possibility of an outage. Without power, it won’t take long to kill the plants by suffocation, drowning, over-feeding, etc.

Hydroponics can work very well for some plants and produce great results. However, it isn’t the best option for every plant type. Root vegetables could grow in a hydroponic system, but it would probably require one of the more expensive methods, and it still might not be worth it.

Summing up the disadvantages of hydroponics:

  • High start-up costs
  • Problems can easily go undetected
  • Crop loss can occur quickly
  • Reliance on electricity
  • Not a good option for every type of plant (especially root vegetables)

Pros of Soil

Growing plants in soil has been a practice since the beginning of society, and it’s not without good reasons. Soil, with many natural nutrients, provides structural stability, oxygen, and temperature insulation

Creating and maintaining a soil-based garden offers much more flexibility in what you want to grow, too. You don’t have to limit yourself to what works well in the specific hydroponic system you’ve built.

In comparison to hydroponics, a soil-based garden can be very cheap. You get more wiggle-room on how much you want to spend, whereas a hydroponic system is fairly rigid in its requirements.

Though growing with soil is more likely to allow for the growth of plant disease, this is preventable as long as the area is kept clean and healthy, which minimizes the capability of bad bacteria to grow. And with soil, the beneficial bugs come out to play.

Even if growing with soil might not be as flashy and interesting as hydroponics, there is one huge advantage that soil has: consistency. Generally, there is no major risk involved in gardening with soil, while hydroponics can go wrong in an instant. Growing in soil is simple, comfortable, and consistent.

Pros of growing with soil:

  • Structural stability
  • More flexibility on what to grow
  • Less expensive than hydroponic systems
  • Beneficial bugs
  • Consistent, not as risky

Cons of Soil

Among the advantages of hydroponics is the simplicity by which the plants get their nutrients. The plants are ordering delivery every day. But in soil, they have to go searching for food, and that means less energy spent growing elsewhere.

You need to provide care for a soil-based garden. In a greenhouse, you can potentially control the temperature and humidity, but outside they can become problems. You have to give the plants shade, dig up weeds, water the plants frequently, and keep things neat and clean to prevent soil-borne diseases.

In short, a soil-based garden requires a lot of upkeep. Not to mention that it will need more water and more space.

The wide range of possibility in what you can grow is balanced by the fact that, if outside, you’ll be limited to the plants’ growing seasons.

Cons of growing with soil:

  • Less direct access to nutrients, possibly lower yields
  • More maintenance needed regularly
  • More water and more space required
  • More frequent cases of plant disease
  • Subject to outside conditions (unless in a greenhouse)

Hydroponics vs. Soil: What’s the Verdict?

pros & cons

Hydroponics

Soil

Pros

  • Uses less water than soil
  • Requires less maintenance
  • Possibly produces higher yields
  • Allows for year-round crop growth
  • Doesn’t take up a lot of space
  • Is less likely to stimulate plant diseases
  • Structural stability
  • More flexibility on what to grow
  • Less expensive than hydroponic systems
  • Beneficial bugs
  • Consistent, not as risky

Cons

  • High start-up costs
  • Problems can easily go undetected
  • Crop loss can occur quickly
  • Reliance on electricity
  • Not a good option for every type of plant (especially root vegetables)
  • Less direct access to nutrients, possibly lower yields
  • More maintenance needed regularly
  • More water and more space required
  • More frequent cases of plant disease
  • Subject to outside conditions (unless in a greenhouse)

When it comes to choosing between growing with soil or with a hydroponic system, only you can decide which way to go. It’s always a good idea to start by researching the conditions that the plants you want to grow will best thrive in, and make decisions based off of that information.

The differences in the two systems should lead you to the right choice for what you’re wanting to accomplish. Either system will do great if you put in the right amount of care. Plus, you could always operate both!

Related Questions

Is soil or hydroponics better?

There's no simple answer, since it depends on what plants you're growing, your budget, and your other needs. Generally, hydroponics is more expensive to start up, but has faster & higher yields, and less likelihood of disease. However, results depend on the plants grown, and hydroponic system used.

How much faster is hydroponics than soil?

It is commonly found that plants grow anywhere from 20% to 50% faster in a hydroponic system than in soil. While this result is not unusual, some scientific experiments have shown that the growth of plants in soil can be equally as fast, if properly done.

What is aquaponics?

Aquaponics is a combination of fish, plants, and bacteria. In an aquaponic system, the excretions of the fish in one tank are converted, by the bacteria, to nutrients that plants can consume. The water is then recycled and recirculated, flowing back to the fish.

Which plants grow best in hydroponic systems?

Generally, water-loving plants, like lettuce, grow best in hydroponic systems. However, this may vary depending on the type of system used. Some systems offer less water, making it more ideal for herbs and small plants. In some other hydroponic systems, the user can specify the amount of water provided.

About the author

Greg Volente

Greg Volente holds a Naturalist Certificate from the Morton Arboretum, and worked for The Nature Conservancy leading environmental education programs and doing natural areas restoration. Besides gardening, he's an avid wildflower enthusiast, and loves botanizing, hiking, and backpacking.