What Is Hydroponics? Growing Plants Without Soil
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What is hydroponics? It is a way of growing plants without soil, in which the roots receive water and dissolved mineral nutrients directly, either from a liquid or from an inert growing medium that holds the solution. Soil does three jobs for a plant: it stores nutrients and water, releases them to the roots, and gives the roots physical support. Hydroponics keeps the first two jobs and replaces the third with a support material. This explainer answers the question directly and then describes how the roots get what they need.
Quick answer
- Hydroponics means growing plants without soil, as the cedwvu.org-hosted “Accessible Gardening” guide puts it: “Hydroponics (hydro-ponic) simply means growing plants without soil.”
- Plants get water and nutrients from a nutrient solution, either in liquid form or held in a growing medium.
- Roots also need oxygen, so most systems move or aerate the solution.
- Because no soil buffers the plants, the system needs regular monitoring and a reliable supply of water and power.
How we chose
The two sources on this page are a Missouri State University workshop presentation and a cedwvu.org-hosted gardening guide. Both were opened on 2026-10-27 and checked for passages that describe the growing method. Quotations are verbatim from the fetched text. Points the sources do not address are marked as gaps. The goal is to describe the mechanism, not to give a complete build guide.
What soil does and what hydroponics replaces
The cedwvu guide explains the role of soil in direct terms: “Soil not only stores and releases nutrients and water. It also supports plants’ root systems.” That sentence lists the three jobs soil performs. The guide then explains that hydroponics can substitute for soil in two general ways, and the difference between them is how the plant receives its nutrients.
The first way uses a growing medium. The guide says that instead of soil, the medium “acts the same as soil. It supports the plant’s root system and holds nutrients and water that plants need to grow.” A medium can be an inert material that does not supply nutrients by itself, so the nutrients must be added through a solution. The second way is a nutrient solution alone, where the roots are suspended in or wetted by liquid with no solid support in the root zone.
The nutrient solution
The Missouri State presentation gives the core idea in its title: “Growing plants in liquid nutrient solutions instead of soil.” The solution is the source of everything the plant takes up through its roots, which means its balance matters more than it would in soil. In a soil bed, minerals are held by soil particles and released gradually. In hydroponics, the nutrients are dissolved in water and available immediately, so the concentration and balance of the solution must be managed.
The Missouri State material lists the nutrient solution among the components of a hydroponic system, along with the growing system and the pump that moves the liquid. Each component depends on the others. The solution feeds the roots, the pump keeps the solution moving, and the growing system holds the plant in place.
Why the plant needs oxygen too
Roots respire, and they need oxygen to do it. In soil, air fills the spaces between particles. In a liquid system, the solution can become low in oxygen unless it is aerated or moved. The cedwvu guide describes the three general delivery approaches that solve this in different ways, and the difference between them is how the roots are exposed to the nutrient. The guide does not give oxygen concentrations, so the level needed for a particular plant is not stated in the source.
Common system types
The cedwvu guide describes solution-based systems in terms of how the nutrient is delivered. It names static solution culture, where the roots come in contact with a nutrient solution that does not move, and continuous flow solution culture, where the solution keeps circulating. It also lists aeroponics as a further approach, in which plants receive nutrients directly. In the guide’s framing, the nutrient solution is what supports and feeds the plants, which is why the system is defined by its solution rather than by its container.
Medium-based systems
A medium-based system holds the roots in an inert material such as a fibrous or porous solid. The medium keeps the plant upright and holds some water between feedings. The cedwvu guide notes that plants grown in medium “are usually planted in containers,” which is a practical feature that distinguishes these systems from solution-only designs. The medium does not feed the plant. The nutrient solution does.
Why the system needs close attention
Soil buffers small mistakes. Its particles hold water and minerals, so a short gap in watering or a small imbalance is softened over time. A hydroponic system has less buffering, so the solution must be checked more often. The Missouri State presentation lists “Constant monitoring” among its disadvantages, and it lists “Initial cost can be higher than soil culture” as another. These are the two drawbacks stated directly in that source.
The same presentation lists advantages. It says hydroponics can “Grow crops where soil is unsuitable,” gives “More control” over conditions, and notes a “Faster growth rate.” These are presented in the source as general advantages. This explainer reports them as the source’s claims and does not measure them.
Why hydroponics is not a soil bed
A soil bed stores a reserve of water and nutrients, so a gardener who misses a day rarely loses the plants. A hydroponic system stores much less reserve, and the plant responds to changes in the solution more quickly. The roots also develop differently. The cedwvu guide explains that in soil, roots “have to search the soil for water and nutrients,” which makes them large. In hydroponics, the guide says, “Roots will not grow out to search for nutrients because plants can find them easily and directly” in the medium and solution. That difference explains why hydroponic plants can be grown closer together.
For a gardener who wants to understand the soil side of the same comparison, the guide on how to make garden soil better covers the structure and organic matter that let soil store water and nutrients. The guide on how to make garden compost quickly explains how organic material is broken down into forms plants can use, which is the step hydroponics skips by supplying minerals directly.
History of the term
The Missouri State presentation gives a short history. It says that “Hydroponics comes from two Greek words ‘hydro’ meaning water and ‘ponos’ meaning labor.” It adds that the word “Hydroponics” was first used in 1929 by Dr. Gericke. The presentation also mentions the use of hydroponic methods by the U.S. Army to feed troops on Pacific islands during the Second World War. These historical points come from a 2017 workshop slide deck and are reported here as the deck states them.
What we could not verify
The two sources explain the basic mechanism, name the components, and describe the main system types. They do not give a single nutrient formula, a target pH, an electrical conductivity range or a schedule for changing the solution. Those figures depend on the plant and the system, and the sources do not supply a table for them.
What the sources do not say
The sources do not state the oxygen level a solution needs, the cost of any specific system, or how often a solution should be replaced. They also do not compare yield or water use with soil in a controlled trial. The Missouri State deck lists “Use less water than soil grown crops” among its advantages, but the excerpt used here does not give a measured figure. A reader who needs those numbers should consult a current university extension guide for the specific crop.
Frequently asked questions
Does hydroponics use soil at all?
No. The cedwvu guide defines hydroponics as growing plants without soil. Some systems use an inert growing medium, but the medium does not supply nutrients on its own, and the nutrients come from a solution.
Where do hydroponic plants get their nutrients?
They get them from a nutrient solution, a liquid in which minerals are dissolved. The Missouri State presentation says hydroponics grows plants in liquid nutrient solutions instead of soil.
Is hydroponics the same as aeroponics?
No. The cedwvu guide lists aeroponics as one of the general delivery approaches, alongside static and continuous flow solution culture. Aeroponics is a different delivery method within the broader category.
Why does hydroponics need monitoring?
The Missouri State presentation lists constant monitoring among the disadvantages. Because the nutrient solution is the plant’s only supply, a change in its balance affects the plant directly, and there is no soil to buffer the change.
Where does the word hydroponics come from?
The Missouri State presentation says it comes from two Greek words, “hydro” meaning water and “ponos” meaning labor, and that Dr. Gericke first used the word in 1929.
Sources
- Accessible Gardening, “Hydroponic Gardening,” cedwvu.org-hosted guide, https://greenthumbs.cedwvu.org/media/1166/hydroponicgardening.pdf, opened 2026-10-27.
- Jennifer Morganthaler, “Introduction to Hydroponics,” Missouri State University Darr College of Agriculture workshop presentation, https://ag.MissouriState.edu/MtnGrv/_Files/GHHT_IntroductiontoHydroponics_JenniferMorganthaler.pdf, opened 2026-10-27.
